Keysight U1251B User And Service Manual
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Keysight U1251B User And Service Manual

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Keysight U1251B and U1252B
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Summary of Contents for Keysight U1251B

  • Page 1 Keysight U1251B and U1252B Handheld Digital Multimeter User’s and Service Guide...
  • Page 2 Limited Rights Do not proceed beyond a WARNING as defined in FAR 27.401 or DFAR 227.7103-5 (c), as applicable in any notice until the indicated conditions are technical data. fully understood and met. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 3: Safety Symbols

    In position of a bi-stable push control CAT III Category III 1000 V overvoltage Equipotentiality 1000 V protection Equipment protected throughout by Category IV 600 V overvoltage CAT IV double insulation or reinforced protection 600 V insulation Keysight U1251B and U1252B User’s and Service Guide...

  • Page 4: Safety Information

    Failure to comply with these precautions or with specific warnings elsewhere in this manual violates safety standards of design, manufacture, and intended use of the instrument. Keysight Technologies assumes no liability for the customer’s failure to comply with these requirements.
  • Page 5 Do not use the test probe if it is damaged. – Do not use any other AC charger adaptor apart from the one certified by Keysight with this product. Keysight U1251B and U1252B User’s and Service Guide...
  • Page 6 Remove power and do not use the product until safe operation can be verified by service-trained personnel. If necessary, return the product to Keysight Technologies Sales and Service Office for service and repair to ensure the safety features are maintained.

  • Page 7: Measurement Category

    Measurement Category The Keysight U1251B and U1252B Handheld Digital Multimeter has a safety rating of CAT III 1000 V/ CAT IV, 600 V. Measurement CAT I are measurements performed on circuits which are not directly connected to the AC mains. For example, measurements on circuits not derived from the AC mains or specially protected (internal) mains-derived circuits.

  • Page 8: Regulatory Markings

    Cet appareil ISM est conforme a la product in domestic household norme NMB-001 du Canada. waste. The CSA mark is a registered trademark of the Canadian Standards Association. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 9: Waste Electrical And Electronic Equipment (Weee) Directive 2002/96/Ec

    To return this unwanted instrument, contact your nearest Keysight Service Center, or visit http://about.keysight.com/en/companyinfo/environment/takeback.shtml for more information. Sales and Technical Support To contact Keysight for sales and technical support, refer to the support links on the following Keysight websites: – www.keysight.com/find/handhelddmm (product-specific information and support, software and documentation updates) –...

  • Page 10: In This Guide

    This chapter contains information on the functions and features that are available for the U1251B and U1252B digital multimeter. 4 Changing The Default Setting This chapter shows you how to change the default factory settings of the U1251B and U1252B and other available setting options. 5 Maintenance This chapter will go through how to troubleshoot the handheld digital multimeter if any problems arise.

  • Page 11: Table Of Contents

    ........46 Keysight U1251B and U1252B User’s and Service Guide...
  • Page 12 ........96 Setting Data Hold/Refresh Hold Mode ......100 Keysight U1251B and U1252B User’s and Service Guide...
  • Page 13 ........140 Keysight U1251B and U1252B User’s and Service Guide...
  • Page 14 ........170 Specifications Keysight U1251B and U1252B User’s and Service Guide...
  • Page 15 ....80 Figure 3-6 1ms peak hold mode operation ....82 Keysight U1251B and U1252B User’s and Service Guide...
  • Page 16 ....... 144 Figure 6-3 Charge terminal alert ......145 Keysight U1251B and U1252B User’s and Service Guide...
  • Page 17 ......164 Table 6-5 Calibration error codes and their respective meanings Keysight U1251B and U1252B User’s and Service Guide...
  • Page 18 THIS PAGE HAS BEEN INTENTIONALLY LEFT BLANK. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 19: Getting Started

    Keysight U1251B and U1252B Handheld Digital Multimeter User’s and Service Guide Getting Started Introducing the U1251B/U1252B Handheld Digital Multimeter Check the shipment This chapter contains information on the Keysight U1251B and U1252B handheld multimeter front panel, rotary switch, keypad, display, terminals and rear panel.

  • Page 20: Introducing The U1251B/U1252B Handheld Digital Multimeter

    – Ambient temperature on second display – Battery capacity indicator – Bright orange LED backlight – Resistance measurement of up to 50 MΩ (for U1251B) and 500 MΩ (for U1252B) – Conductance measurement from 0.01 nS (100 GΩ) ∼ 50 nS –...

  • Page 21: Check The Shipment

    – Quick Start Guide – Certificate of Calibration Contact your nearest Keysight Sales Office if any of the above are missing. Inspect the shipping containing for damage. Signs of damage may include a dented or torn shipping container or cushioning material that indicates signs of unusual stress or compacting.

  • Page 22: Installing The Battery

    2 On the rear panel, turn the screw on the battery cover counterclockwise from the LOCK position to OPEN. 3 Slide the battery cover down and lift the battery cover up to insert the battery. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 23: Adjusting The Tilt-Stand

    ° is parallel to the ground before pulling the stand outwards to its maximum reach. IR-USB cable To PC (host) Tilt-stand at 30 º Figure 1-2 Tilt-stand at 30 ° Keysight U1251B and U1252B User’s and Service Guide...

  • Page 24: Figure 1-3 Tilt-Stand At Hanging Position

    3. Flip the tilt-stand over until this side of the stand is facing the multimeter as 4. Re-attach the tilt-stand to an upright position opposed to facing you Figure 1-3 Tilt-stand at hanging position Keysight U1251B and U1252B User’s and Service Guide...

  • Page 25: The Front Panel At A Glance

    Getting Started The front panel at a glance Display Keypad Rotary Switch Terminal Connectors Figure 1-4 U1252B front panel Keysight U1251B and U1252B User’s and Service Guide...

  • Page 26: The Rear Panel At A Glance

    Getting Started The rear panel at a glance IR Communication Port Test probe holders Tilt-stand Battery access cover Figure 1-5 Rear panel Keysight U1251B and U1252B User’s and Service Guide...

  • Page 27: The Rotary Switch At A Glance

    Capacitance or Temperature DC µA, AC µA, AC+DC µA DC mA, DC current, AC mA, AC current or AC+DC current Square-wave output, Duty cycle, or Pulse width output (for U1252B) and OFF (for U1251B) Keysight U1251B and U1252B User’s and Service Guide...

  • Page 28: The Keypad At A Glance

    1 ms Peak Hold mode. Press subtracted from subsequent measurements. Press to scroll through Max and Min peak readings. again to see the relative value that has been saved. Keysight U1251B and U1252B User’s and Service Guide...
  • Page 29 For pulse and duty cycle measurement, press to switch trigger slope to positive or negative. When meter is in peak or dynamic-recording mode, press to restart 1 ms peak hold or dynamic recording mode. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 30: The Display At A Glance

    3 To set the rotary switch at square wave out position, press only the Dual, Range and Hold buttons or turn the rotary switch to another position. (U1252B only) The LCD signs are explained in the following tables. Figure 1-8 Display symbols Keysight U1251B and U1252B User’s and Service Guide...

  • Page 31: Table 1-3 General Display Symbols

    – Discharging capacitor as capacitance measurement Low battery indication Auto power off enable Refresh (auto) Hold Trigger (manual) Hold TRIG Dynamic Recording mode: Present value on primary display MAXMINAVG Dynamic Recording mode: Maximum value on primary display Keysight U1251B and U1252B User’s and Service Guide...

  • Page 32: Table 1-4 Primary Display Symbols

    Resistance units: Ω, kΩ, MΩ Conductance unit Voltage units: mV, V Current units: µA, mA, A µmA Duty cycle measurement Pulse width unit Capacitance units: nF, µF, mF µmnF Celsius temperature unit ºC Keysight U1251B and U1252B User’s and Service Guide...

  • Page 33: Table 1-5 Secondary Display Symbols

    When 4–20 mA% scale or 0–20 mA% scale is indicated on the primary display, the bar graph represents the current value and not the percentage value. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 34: Table 1-6 Analog Bar Range And Counts

    See the table below. Table 1-6 Analog bar range and counts Range Counts/segments Used for the function 2500 V, Ω , Diode 2500 V, A, Ω 2500 V, A, Ω , nS Keysight U1251B and U1252B User’s and Service Guide...

  • Page 35: Selecting Display With The Hz Button

    AC + DC V (AC + DC voltage) Duty cycle (%) Frequency (Hz) Pulse width (ms) AC mV (AC voltage) Duty cycle (%) Frequency (Hz) Pulse width (ms) DC mV (DC voltage) Duty cycle (%) Keysight U1251B and U1252B User’s and Service Guide...

  • Page 36: Table 1-7 Selecting Display With The Hz Button

    - 1 - to select frequency division by 1 [for U1252B] Duty cycle (%) Hz (Frequency counter) - press Frequency (Hz) - 100 - to select frequency division by 100 [for U1252B] Keysight U1251B and U1252B User’s and Service Guide...

  • Page 37: Selecting Display With The Dual Button

    AC + DC V Ambient temperature °C or °F AC mV Hz (AC coupling) AC mV (AC voltage) dBm or dBV AC mV DC mV AC mV Ambient temperature °C or °F Keysight U1251B and U1252B User’s and Service Guide...

  • Page 38: Table 1-8 Selecting Display With The Dual Button

    AC + DC μA Ambient temperature °C or °F DC mA Hz (DC coupling) DC mA AC mA (DC current) % (0–20 or 4–20) DC mA DC mA Ambient temperature °C or °F Keysight U1251B and U1252B User’s and Service Guide...
  • Page 39 / V / Ω / nS Ambient temperature °C or °F (Diode)/ (Resistance)/ nS (Conductance) °C (°F) Ambient temperature °C or °F (Temperature) °C (°F) Ambient temperature °C or °F / 0 °C compensation (select by pressing Keysight U1251B and U1252B User’s and Service Guide...

  • Page 40: Selecting Display With The Shift Button

    (AC + DC Voltage) AC + DC mV Ω Ω (Resistance) Ω Diode (Diode test and Frequency) Capacitance Temperature (Capacitance and Temperature) DC μA AC μA (AC Current) AC + DC μA [for U1252B] Keysight U1251B and U1252B User’s and Service Guide...

  • Page 41: The Terminals At A Glance

    [b] Press for more than 1 second to return to AC V measurement only. The terminals at a glance To avoid damaging the multimeter, do not exceed the input limit. WARNING Keysight U1251B and U1252B User’s and Service Guide...

  • Page 42: Figure 1-9 Connector Terminals

    <0.3 A Ω μA. mA 440 mA / 1000 V 30 kA fast-acting fuse 11 A / 1000 V 30 kA fast-acting fuse for U1252B 440 mA / 1000 V fast-acting fuse Keysight U1251B and U1252B User’s and Service Guide...
  • Page 43 Keysight U1251B and U1252B Handheld Digital Multimeter User’s and Service Guide Making Measurements Understanding The Measurement Instructions Measuring Voltage Frequency Counter Measuring Resistance, Conductance and Testing Continuity Testing Diodes Measuring Capacitance Measuring Temperature Alerts and Warning During Measurement This chapter contains information on how to make measurements using the...

  • Page 44: Making Measurements

    Probe the test points Read the results on the display Measuring Voltage The U1251B and U1252B offer true-RMS readings for AC measurements that are accurate for sine waves, square waves, triangle waves, staircase waves, and other waveforms without any DC offset.

  • Page 45: Measuring Ac Voltage

    See Table 1-8 NOTE “Selecting display with the Dual button” on page 37 for a list of the different combinations available on the secondary display. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 46: Measuring Dc Voltage

    – To avoid possible electric shock or personal injury, enable the Low Pass Filter to verify the presence of hazardous DC voltages. Displayed DC voltage values can be influenced by high frequency AC components and must be filtered to assure an accurate reading. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 47: Measuring Ac And Dc Signals (U1252B Only)

    Note the AC voltage range, then manually select a DC voltage range equal to or higher than the AC range. This procedure improves the accuracy of the DC measurement by ensuring that the input protection circuits are not activated. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 48: Measuring Current

    A. – Press to display dual measurements. See Table 1-8 “Selecting display with the Dual button” on page 37 for a list of dual measurements available. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 49: Figure 2-3 Measuring Ma And Ma Current

    Making Measurements Black Lead Red Lead Figure 2-3 Measuring μA and mA current Keysight U1251B and U1252B User’s and Service Guide...

  • Page 50: Percentage Scale Of 4 Ma To 20 Ma

    – The percentage scale for 4 mA to 20 mA or 0 mA to 20 mA is calculated using its corresponding DC mA measurement. The U1251B and U1252B will automatically optimize the best resolution according to Table 2-2 below.

  • Page 51: Figure 2-4 Measuring Scale Of 4-20 Ma

    Making Measurements Black Lead Red Lead Figure 2-4 Measuring scale of 4-20 mA Keysight U1251B and U1252B User’s and Service Guide...

  • Page 52: A (Ampere) Measurement

    Connect the red and black test leads to the 10 A input terminal A and COM NOTE respectively. The meter is set to A measurement automatically when the red test lead is plugged into the A terminal. Black Lead Red Lead Figure 2-5 A (ampere) current measurement Keysight U1251B and U1252B User’s and Service Guide...

  • Page 53: Frequency Counter

    – The signal is out of range if the reading is still unstable after the above step. – While the secondary display shows “-1-“, you may scroll through the pulse width (ms), duty cycle (%) and frequency (Hz) measurements by pressing Keysight U1251B and U1252B User’s and Service Guide...

  • Page 54: Figure 2-6 Measuring Frequency

    Making Measurements Black Lead Red Lead Figure 2-6 Measuring frequency Keysight U1251B and U1252B User’s and Service Guide...

  • Page 55: Measuring Resistance, Conductance And Testing Continuity

    Set up the multimeter to measure resistance as shown in Figure 2-7. Then probe the test points (by shunting the resistor) and read the display. Black Lead Red Lead Figure 2-7 Measuring resistance Keysight U1251B and U1252B User’s and Service Guide...

  • Page 56: Figure 2-8 Audible Continuity, Conductance, And Resistance Test

    Making Measurements Press to scroll through audible continuity, conductance and resistance tests as shown in Figure 2-8. Press Audible continuity Press Press Figure 2-8 Audible continuity, conductance, and resistance test. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 57: Table 2-3 Audible Continuity Measurement Range

    As the high-resistance readings are susceptible to noise, you can capture the average readings by using the Dynamic Recording mode. Refer to the section “Dynamic Recording” on page 72 for more information. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 58: Figure 2-9 Conductance Measurement

    Making Measurements Black Lead Red Lead Figure 2-9 Conductance measurement Keysight U1251B and U1252B User’s and Service Guide...

  • Page 59: Testing Diodes

    – The diode is considered shorted if the meter displays approximately 0 V in both forward and reverse bias modes, and the meter beeps continuously. – The diode is considered open if the meter displays “OL” in both forward and reverse bias modes. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 60: Figure 2-10 Measuring Forward Bias Of Diode

    Making Measurements Black Lead Red Lead Figure 2-10 Measuring forward bias of diode Keysight U1251B and U1252B User’s and Service Guide...

  • Page 61: Figure 2-11 Measuring Reverse Bias Of Diode

    Making Measurements Black Lead Red Lead Figure 2-11 Measuring reverse bias of diode Keysight U1251B and U1252B User’s and Service Guide...

  • Page 62: Measuring Capacitance

    Set up the multimeter as shown in Figure 2-12. Use the red probe lead on the positive terminal of the capacitor and the black probe lead on the negative terminal and read the display. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 63: Figure 2-12 Capacitance Measurements

    Making Measurements Red Lead Black Lead Figure 2-12 Capacitance measurements Keysight U1251B and U1252B User’s and Service Guide...

  • Page 64: Measuring Temperature

    6 When measuring above the ambient temperature, move the thermocouple along the surface until you get the highest temperature reading. 7 When measuring below ambient temperature, move the thermocouple along the surface until you get the lowest temperature reading. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 65: Figure 2-13 Connecting The Thermal Probe Into The Non-Compensation Transfer Adapater

    The 0 °C compensation adapter assists in measuring the relative temperature immediately. Figure 2-13 Connecting the thermal probe into the non-compensation transfer adapater Figure 2-14 Connecting the probe with adapter into the multimeter Keysight U1251B and U1252B User’s and Service Guide...
  • Page 66 3 After a constant reading is obtained, press to set the reading as the relative reference temperature. 4 Touch the measurement surface with the thermocouple probe. 5 Read the display for the relative temperature. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 67: Figure 2-15 Surface Temperature Measurement

    Making Measurements Figure 2-15 Surface temperature measurement Keysight U1251B and U1252B User’s and Service Guide...

  • Page 68: Alerts And Warning During Measurement

    The primary display indicates a flashing “A-Err” until the test lead is removed from the A input terminal. Refer to Figure 2-16. Figure 2-16 Input terminal warning Keysight U1251B and U1252B User’s and Service Guide...

  • Page 69: Charge Terminal Alert

    5 V and the rotary switch is not set to the corresponding location. The primary display indicates a flashing “Ch.Err” until the lead is removed from the input terminal. Refer to Figure 2-17 below. Figure 2-17 Charge terminal alert Keysight U1251B and U1252B User’s and Service Guide...
  • Page 70 Making Measurements THIS PAGE HAS BEEN INTENTIONALLY LEFT BLANK. Keysight U1251B and U1252B User’s and Service Guide...
  • Page 71 Keysight U1251B and U1252B Handheld Digital Multimeter User’s and Service Guide Functions and Features Dynamic Recording Data Hold (Trigger Hold) Refresh Hold Null (Relative) Decibel Display 1 ms Peak Hold Data Logging Square Wave Output (for U1252B) Remote Communication This chapter contains information on the functions and features that are available...

  • Page 72: Functions And Features

    – The average value is the true average of all the measured values taken in the Dynamic Recording mode. If an overload is recorded, the averaging function will stop and the average value becomes “OL” (overload). is disabled in Dynamic Recording mode. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 73: Figure 3-1 Dynamic Recording Mode Operation

    Press Max Min for > 1 sec or press for > 1 sec Press Max Min Press Max Min for > 1 sec or press for > 1 sec Figure 3-1 Dynamic recording mode operation Keysight U1251B and U1252B User’s and Service Guide...

  • Page 74: Data Hold (Trigger Hold)

    3 Press and hold for more than 1 second to quit the data hold function. Press Press Measurement update Press press for > 1 sec. Figure 3-2 Data hold mode operation Keysight U1251B and U1252B User’s and Service Guide...

  • Page 75: Refresh Hold

    The symbol will remain on and the multimeter will emit a tone to remind you of this. 4 Press again to quit the Refresh Hold function. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 76: Figure 3-3 Refresh Hold Mode Operation

    – For resistance and diode measurements, the holding value will not be updated if the reading is in “OL” (open state). – The holding value may not be updated when the reading does not reach a stable state for all measurements. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 77: Null (Relative)

    – When taking a DC voltage measurement, the thermal effect will influence the accuracy. Short the test leads and press Null once the displayed value is stable in order to zero out the display. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 78: Figure 3-4 Null (Relative) Mode Operation

    Functions and Features Press Press Auto-return after 3 seconds Flash Press as NULL is flashing on the display Figure 3-4 Null (relative) mode operation Keysight U1251B and U1252B User’s and Service Guide...

  • Page 79: Decibel Display

    The dBm or the dBV measurements can be selected at the ACV position. The selection will be the reference for other voltage measurements. 2 Press for more than 1 second to exit this mode. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 80: Figure 3-5 Dbm/Dbv Display Mode Operation

    > 1 sec. Press for > 1 sec. Press Press Press for > 1 sec. Only when rotary switch is at Press position Press Press Press Figure 3-5 dBm/dBV display mode operation Keysight U1251B and U1252B User’s and Service Guide...

  • Page 81: Ms Peak Hold

    3 Press and hold for more than 1 second to exit this mode. 4 According to the measurements shown in Figure 3-6 on page 82, the crest Factor will be 2.5048/1.768 =1.416. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 82: Figure 3-6 1Ms Peak Hold Mode Operation

    Functions and Features Press for > 1 sec. Press Start to capture Start to capture Press Press Press Figure 3-6 1ms peak hold mode operation Keysight U1251B and U1252B User’s and Service Guide...

  • Page 83: Data Logging

    To use the data logging function, you will need to connect the multimeter to a NOTE PC using the U1173A IR-to-USB cable (purchased separately) and download the data logging software from Keysight’s website. Please go to: http://www.keysight.com/find/hhTechLib to download the software.

  • Page 84: Figure

    The maximum data that can be stored is 100 entries. When the 100 entries are NOTE filled, the secondary display indicates “FULL”, as shown in Figure 3-8. Press for > 1 sec. Auto-return after 3 seconds Figure 3-8 Full Log Keysight U1251B and U1252B User’s and Service Guide...

  • Page 85: Interval Logging

    “FULL” is indicated on the secondary display. 2 Press for more than 1 second to exit this mode. When interval (automatic) logging is enabled, all keypad operations are NOTE disabled, except for the Log function. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 86: Figure 3-9 Interval (Automatic) Logging Mode Operation

    Functions and Features Press for > 1 sec. First interval Press for > 1 sec. Press Last interval for > 1 sec. Last +1 interval Stop logging Figure 3-9 Interval (Automatic) logging mode operation Keysight U1251B and U1252B User’s and Service Guide...

  • Page 87: Reviewing Logged Data

    1 second to exit mode. 6 During the data review in either manual or interval logging mode, press for more than one second to clear all the logged values. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 88: Figure 3-10 Log Review Mode Operation

    Press Press to clear all to clear all Press Log Press Log manual interval for > 1 sec for > 1 sec logs logs Press View Figure 3-10 Log review mode operation Keysight U1251B and U1252B User’s and Service Guide...

  • Page 89: Square Wave Output (For U1252B)

    (%) on the primary display. 4 Press to adjust the duty cycle. Duty cycle can be set for 256 steps and each step is 0.390625%. The display only indicates the best resolution with 0.001%. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 90: Figure 3-11 Frequency Adjustment For Square Wave Output

    The pulse width can be set for 256 steps and each step is 1/ (256 x Frequency). The display range automatically adjusts in the range of 9.9999~9999.9 ms. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 91: Figure 3-12 Pulse Width Adjustment For Square Wave Output

    Functions and Features Press Press Press Press Figure 3-12 Pulse wid th adjustment for square wave output Keysight U1251B and U1252B User’s and Service Guide...

  • Page 92: Figure 3-13 Pulse Width Adjustment For Square Wave Output

    Functions and Features Press Press Press Press Figure 3-13 Pulse width adjustment for square wave output Keysight U1251B and U1252B User’s and Service Guide...

  • Page 93: Remote Communication

    IR-USB cable, to be used with an application software downloadable from the Keysight website. For details on performing PC to meter remote communication click on Help after launching the Keysight GUI Data Logger Software or refer to the GUI Data Logger Quick Start Guide (U1251-90023) for more information.
  • Page 94 Functions and Features THIS PAGE HAS BEEN INTENTIONALLY LEFT BLANK. Keysight U1251B and U1252B User’s and Service Guide...
  • Page 95 Setting Data Bit Setting Echo Mode Setting Print Mode Returning to Default Factory Settings Setting the Battery Voltage Setting the Filter This chapter shows you how to change the default factory settings of the U1251B and U1252B and other available setting options.

  • Page 96: Changing The Default Setting

    “Available setting options in Setup mode,” for details of available options. 3 Press to save changes. These parameters will remain in the non-volatile memory. 4 Press for more than 1 second to exit Setup mode. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 97: Table 4-1 Available Setting Options In Setup Mode

    (remote control with PC) Sets the baud rate for 2400 Hz, 4800 Hz, 9600 the remote bAUd Baud rate 9600 Hz Hz, 19200 Hz communication (remote control with PC) Keysight U1251B and U1252B User’s and Service Guide...
  • Page 98 K-type Thermocouple t.CoUP tYPE Sets the thermocouple tYPE type to J-type Enables manual data Hand logging d-LoG Data logging Hand Sets the interval for 1–9999 s automatic data logging Keysight U1251B and U1252B User’s and Service Guide...
  • Page 99 [b] For b-Lit, APF, rEF and d-LoG menu items, the user can select the digit to be adjusted by pressing [c] This menu option is only available for the U1252B. [d] To view the tEMP menu item, press for more than 1 second. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 100: Setting Data Hold/Refresh Hold Mode

    (auto trigger). When the variation of the measuring value exceeds the setting of the variation count, the Refresh Hold will be ready to trigger. Press Press Press Press Press Figure 4-1 Data hold/Refresh hold setup Keysight U1251B and U1252B User’s and Service Guide...

  • Page 101: Setting Data Logging Mode

    3 Press and hold for more than 1 second to switch between manual and interval data logging setup. Press Press Press Press set interval > 1 second Press Press Figure 4-2 Data logging setup Keysight U1251B and U1252B User’s and Service Guide...

  • Page 102: Setting Thermocouple Types (U1252B Only)

    Setting Thermocouple Types (U1252B only) The thermocouple sensor types that can be selected are type K (default) or type J. Press to switch between the J and the K type. Press Figure 4-3 Thermocouple type setup Keysight U1251B and U1252B User’s and Service Guide...

  • Page 103: Setting Reference Impedance For Dbm Measurement

    Setting Reference Impedance for dBm Measurement The reference impedance can be set from 1 to 9999 Ω. The default value is 50 Ω. Press Press Press Press Figure 4-4 Reference impedance for dBm measurement setup Keysight U1251B and U1252B User’s and Service Guide...

  • Page 104: Setting Minimum Frequency Measurement

    The minimum frequency setup influences the measuring rates for frequency, duty cycle and pulse width. The typical measuring rate is based on the minimum frequency of 1 Hz. Press Press Press Press Press Figure 4-5 Minimum frequency setup Keysight U1251B and U1252B User’s and Service Guide...

  • Page 105: Setting Temperature Unit

    – Celsius only (°C on primary display) single display setting – Celsius-Fahrenheit (d-CF) and Fahrenheit-Celsius (d-FC) dual display setting. NOTE Primary-Secondary Display can be swapped by pressing – Fahrenheit only (°F on primary display) single display setting. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 106: Figure 4-6 Temperature Unit Setup

    Changing The Default Setting Press Press Press Press Press Figure 4-6 Temperature unit setup Keysight U1251B and U1252B User’s and Service Guide...

  • Page 107: Setting Auto Power Saving Mode

    – To activate the meter after it has “auto powered-off”, turn the rotary switch to the OFF position. Then turn it back on again. – will be shown on the display during subsequent measurements. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 108: Figure 4-7 Auto Power Saving Setup

    Changing The Default Setting Press Press Press Press Press Figure 4-7 Auto power saving setup Keysight U1251B and U1252B User’s and Service Guide...

  • Page 109: Setting Percentage (%) Scale Readout

    — 4–20 mA or 0–20 mA as proportional to 0~100%. The 25% scale readout represents DC 8 mA at 4–20 mA and DC 5 mA at 0–20 mA. Press Figure 4-8 % scale readout setup Keysight U1251B and U1252B User’s and Service Guide...

  • Page 110: Setting Beep Frequency

    Changing The Default Setting Setting Beep Frequency The driving frequency can be set to 2400, 1200, 600, or 300Hz. “OFF” disables the beep. Press Press Press Press Press Press Figure 4-9 Beep frequency setup Keysight U1251B and U1252B User’s and Service Guide...

  • Page 111: Setting Backlight Timer

    – The timer can be set to 1—99 seconds. The backlight will turn off automatically after the set period. – “0FF” disables turning off backlit automatically. Press Press Press Press Press Figure 4-10 Backlit timer setup Keysight U1251B and U1252B User’s and Service Guide...

  • Page 112: Setting Baud Rate

    Setting Baud Rate Select the baud rate for remote control. The available settings are 2400, 4800, 9600, and 19200 Hz. Press Press Press Press Press Figure 4-11 Baud rate setup remote control Keysight U1251B and U1252B User’s and Service Guide...

  • Page 113: Setting Parity Check

    Changing The Default Setting Setting Parity Check Select the parity check for remote control. It can be set to none, even, or odd bit. Press Press Press Press Figure 4-12 Parity check setup Keysight U1251B and U1252B User’s and Service Guide...

  • Page 114: Setting Data Bit

    Changing The Default Setting Setting Data Bit Select the data bit for remote control. It can be set to either 8 or 7 bits. Press Figure 4-13 Data bit setup for remote control Keysight U1251B and U1252B User’s and Service Guide...

  • Page 115: Setting Echo Mode

    – Echo ON enables the return of characters to the PC in remote communication. – Echo OFF disables the return of characters to the PC. Press Figure 4-14 Echo mode setup for remote control Keysight U1251B and U1252B User’s and Service Guide...

  • Page 116: Setting Print Mode

    In this mode, the meter automatically sends the newest data to the host continuously but does not accept any commands from the host. flashes during the Print operation. Press Figure 4-15 Print mode setup for remote control Keysight U1251B and U1252B User’s and Service Guide...

  • Page 117: Returning To Default Factory Settings

    Temperature setting. – The Reset menu item automatically reverts to Refresh Hold menu item after reset has taken place. Press for > 1 sec. Figure 4-16 Reset setup Keysight U1251B and U1252B User’s and Service Guide...

  • Page 118: Setting The Battery Voltage

    Changing The Default Setting Setting the Battery Voltage Battery type for the multimeter can be set to either 7.2 V or 8.4 V. Press Figure 4-17 Battery voltage selection Keysight U1251B and U1252B User’s and Service Guide...

  • Page 119: Setting The Filter

    – During AC or Hz measurement (on primary or secondary display), DC filter will be automatically disabled. – For firmware version 2.17 and below, the Filter function is switched off by default. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 120: Table 4-2 Filter Defaults

    Changing The Default Setting Table 4-2 Filter defaults Parameter Defaul t setting Firmware version 2.17 and below FiLtEr 2.18 and above [a] Firmware is factory-installed and not field-upgradeable. Keysight U1251B and U1252B User’s and Service Guide...
  • Page 121 Keysight U1251B and U1252B Handheld Digital Multimeter User’s and Service Guide Maintenance Introduction Replaceable Parts This chapter will go through how to troubleshoot the handheld digital multimeter if any problems arise.

  • Page 122: Maintenance

    If your meter has the rechargeable battery type, refer to the section “Charging the battery” on page 125. Keysight U1251B and U1252B User’s and Service Guide...
  • Page 123 3 Lift the battery cover up. 4 Replace the specified battery. 5 Reverse the above steps to close the cover. List of compatible batteries for the Keysight U1251B: NOTE – 9 V Alkaline non-chargeable battery (ANSI/NEDA 1604A or IEC 6LR61) –...

  • Page 124: Storage Considerations

    After the first charge, it is recommended that you fully charge the battery periodically, even when it is not in use. This is because the Ni-MH rechargeable battery pack may drain with time. The performance of the rechargeable battery may degrade with time. NOTE Keysight U1251B and U1252B User’s and Service Guide...

  • Page 125: Charging The Battery

    To discharge, simply run the multimeter under the battery's power until it shuts down or the low battery warning appears. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 126: Table 5-1 Battery Voltage And Corresponding Percentage Of Charges In Standby And Charging Modes

    Battery voltage and corresponding percentage of charges in standby and charging modes Cond ition Battery vol tage Proportional percentage Trickle (SBY) 7.0 V to 9.6 V 0% to 100% Charging 7.2 V to 10.0 V 0% to 100% Keysight U1251B and U1252B User’s and Service Guide...

  • Page 127: Figure 5-2 Battery Capacity Display As Trickle

    The self-test takes about 2 to 3 minutes. Avoid pressing any button during the self-test. A message is diplayed as shown in Figure 5-3. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 128: Figure 5-3 Self-Test

    Maintenance Figure 5-3 Self-test Table 5-2 Error messages Error Error message 1 No battery inside 2 Faulty battery 3 Battery is fully charged Keysight U1251B and U1252B User’s and Service Guide...
  • Page 129 220 minutes. The secondary display will count down the charging time. During charging, no buttons can be pressed. The error message may appear during charging to alert the user of any overcharging of the battery. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 130: Figure 5-4 Charging Mode

    8 Remove the DC adapter when the C–End message appears on the secondary display. Do not turn the rotary switch before removing the adapter from the terminals. Figure 5-5 Charge end and trickle state Keysight U1251B and U1252B User’s and Service Guide...

  • Page 131: Figure 5-6 Battery Charging Procedure

    Maintenance Press to start charge Error Error-Full Error-Empty Battery can be charged Fully charged Figure 5-6 Battery charging procedure Keysight U1251B and U1252B User’s and Service Guide...

  • Page 132: Fuse Checking Procedure

    Figure 5-8 for the respective positions of Fuse 1 and Fuse 2. 1 Set the rotary switch to 2 Connect the red test lead to the input terminal Figure 5-7 Fuse checking procedures Keysight U1251B and U1252B User’s and Service Guide...

  • Page 133: Table 5-3 Measurement Readings For Fuse Checking

    6 Replace the fuse when OL is displayed. Table 5-3 Measurement readings for fuse checking Fuse OK Replace fuse (approximately) Current input terminal Fuse Fuse rating Displayed read ings 440 mA/1000 V 6.2 MΩ 11 A/1000 V 0.06 Ω Keysight U1251B and U1252B User’s and Service Guide...

  • Page 134: Replacing The Fuse

    8 Ensure that the rotary switch on the top case and the circuit board switch stay on the OFF position. 9 Then re-fasten the circuit board and the bottom cover. 10 Refer to the table below for the part number, rate, and size of the fuses. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 135: Figure 5-8 Fuse Replacement

    Fuse Keysight part Rating Size Type number 2110-1400 440mA/1000V 10 mm x 35 mm Fast blow Fuse 2110-1402 11A/1000V 10 mm x 38 mm Fuse 1 Fuse 2 Figure 5-8 Fuse replacement Keysight U1251B and U1252B User’s and Service Guide...

  • Page 136: Troubleshooting

    9600, n, 8, 1) – Driver install for IR-USB. Notes for basic troubleshooting procedures table: [a] Never turn the rotary switch of the multimeter from the OFF position when it is charging. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 137: Replaceable Parts

    To order replaceable parts from Keysight, do the following: 1 Contact your nearest Keysight Sales Office or Service Center. 2 Identify the parts by the Keysight part number shown in the support parts list. 3 Provide the instrument model number and serial number.
  • Page 138 Maintenance THIS PAGE HAS BEEN INTENTIONALLY LEFT BLANK. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 139: Performance Tests And Calibration

    Keysight U1251B and U1252B Handheld Digital Multimeter User’s and Service Guide Performance Tests and Calibration Calibration Overview Recommended Test Equipment Basic Operating Test Test Considerations Calibration Security Performance Verification Tests Calibration Process Adjustments Consideration This chapter contains the performance test procedures and the adjustment...

  • Page 140: Calibration Overview

    The nonvolatile EEPROM calibration memory is retained even when the power is switched off. Keysight Technologies calibration services When your instrument is due for calibration, contact your local Keysight Service Center to enquire about recalibration services. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 141: Calibration Interval

    Specifications are only guaranteed within the period stated from the last adjustment. Keysight recommends that readjustment should be performed during the calibration process for best performance. This will ensure that the U1251B/ U1252B will remain within the specifications for the next calibration interval. This criterion for the re-adjustment provides the best long–term stability.

  • Page 142: Recommended Test Equipment

    If the exact instrument is not available, substitute calibration standards of equivalent accuracy. A suggested alternative method would be to use the Keysight 3458A 8½ – Digit Digital Multimeter to measure less accurate yet stable sources. The output value measured from the source can be entered into the instrument as the target calibration value.

  • Page 143: Basic Operating Test

    Testing the display Press the Hold button and turn on the meter to view all segments of the display. Compare the display with the example in Table 6-1. Figure 6-1 LCD display Keysight U1251B and U1252B User’s and Service Guide...

  • Page 144: Current Terminal Test

    6-2. The primary display will keep flashing unless the test lead is removed from “A” terminal. Before conducting this test, make sure the beep function is not disabled in NOTE setup. Figure 6-2 Input warning Keysight U1251B and U1252B User’s and Service Guide...

  • Page 145: Charge Terminal Alert Test

    “Ch.Err” until the lead is removed from the terminal. Figure 6-3 Charge terminal alert Before conducting this test, make sure the beep function is not disabled at NOTE setup. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 146: Test Considerations

    – Ensure that the ambient relative humidity is less than 80%. – Allow a warm-up period of five minutes. – Use shielded twisted pair PTFE-insulated cables to reduce settling and noise errors. Keep the input cables as short as possible. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 147: Calibration Security

    You can unsecure the instrument from the front panel. The security code can NOTE only be changed from the front panel after the instrument has been unsecured. “To unsecure the instrument without the security code” on page 156 if you forget your security code. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 148: Performance Verification Tests

    After acceptance, you should repeat the performance verification tests at every calibration interval. Make sure you have read the “Test Considerations” on page 146 before doing the NOTE performance verification tests. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 149: Table 6-2 Verification Test

    ± 500 mHz Press button to go to frequency mode 0.01% – 99.99% 5.0 Vpp @ 50%, ± 0.315% ± 0.315% Press button to go to Square Wave, Duty Cycle mode 50 Hz Keysight U1251B and U1252B User’s and Service Guide...
  • Page 150 ± 0.2 mV ± 0.175 mV – 500 mV ± 0.2 mV ± 0.175 mV 1000 mV 1000 mV ± 0.8 mV ± 0.75 mV – 1000 mV ± 0.8 mV ± 0.75 mV Keysight U1251B and U1252B User’s and Service Guide...
  • Page 151 Ω position 5 kΩ 5 kΩ ± 4.5 Ω ± 3 Ω 50 kΩ 50 kΩ ± 45 Ω ± 30 Ω 500 kΩ 500 kΩ ± 450 Ω ± 300 Ω Keysight U1251B and U1252B User’s and Service Guide...
  • Page 152 ± 1.05 μF 1000.0 μF 1000.0 μF ± 10.5 μF ± 10.5 μF 10.00 mF 10.00 mF ± 0.105 mF ± 0.105 mF 100.00 mF 10.00 mF ± 0.4 mF ± 0.4 mF Keysight U1251B and U1252B User’s and Service Guide...
  • Page 153 Caution: Connect the calibrator to handheld mul timeter's A and COM terminals before applying 5A and 10A ± 16 mA ± 16 mA 10 A ± 40 mA ± 35 mA 10 A Keysight U1251B and U1252B User’s and Service Guide...
  • Page 154 — To perform the measurement, connect one end of the K-type thermocouple (with miniature TC connector on both ends) to the 5520A TC output, and the other end to the multimeter via a TC-to-banana adapter. Allow at least 1 hour for the multimeter to stabilize. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 155: Unsecuring The Instrument For Calibration

    Use the to select each character. 5 Press (Save) when done. 6 If the correct security code is entered, the secondary display will show PASS. Keysight U1251B and U1252B User’s and Service Guide...
  • Page 156 The primary display shows 5555 and the secondary display shows SECUr. 4 Press for more than 1 second to enter the Set Default Security Code mode. The secondary display shows SEr.no and the primary display shows 5555. Keysight U1251B and U1252B User’s and Service Guide...
  • Page 157 Now you can use 1234 as the security code. If you want to enter a new security code, see “To change the instrument calibration security code from the front panel” on page 156. Make sure you record the new security code. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 158: Calibration Process

    5 Secure the instrument against calibration. 6 Note the new security code and calibration count in the instrument's maintenance records. Make sure to quit the Adjustment Mode before turning off the instrument. NOTE Keysight U1251B and U1252B User’s and Service Guide...

  • Page 159: Using The Front Panel For Adjustments

    1 Use the edit keys to select each digit in the primary display. 2 Use the and the arrow keys to advance through the digits 0 through 9. 3 Press when done to start calibration. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 160: Adjustments Consideration

    1 hour with the K-type thermocouple connected between the instrument and the calibration source. Never turn off the instrument during an adjustment. This may delete the CAUTION calibration memory for the present function. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 161: Valid Adjustment Input Values

    0.9 to 1.1 x Full Scale 10 nF, 100 nF, 1000 nF, 10 µF, 100 µF, Make sure to provide 0 °C with ambient 1000 µF, 10 mF / 0 °C compensation Keysight U1251B and U1252B User’s and Service Guide...

  • Page 162: Adjustment Procedure

    7 Enter the actual applied input (see “Entering Adjustment Values” page 159). 8 Press to start the adjustment. The CAL flashes in the secondary display to indicate that the calibration is in progress. Keysight U1251B and U1252B User’s and Service Guide...
  • Page 163 Repeat the adjustment procedure. 9 Repeat steps 1 through 8 for each adjustment point. 10 Verify the adjustments using the “Performance Verification Tests” on page 148 Table 6-4. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 164: Table 6-4 Adjustment Table

    (for model U1251B) 3.0000 V 3.0000 V 50 V 30 V 30.000 V 30.000 V 500 V 300 V 300.00 V 300.00 V 1000 V 1000 V 1000.0 V 1000.0 V Keysight U1251B and U1252B User’s and Service Guide...
  • Page 165 30.000 mV 30.000 mV mV mode 30 mV, 20 kHz * 30.000 mV 30.000 mV 500 mV 30 mV, 1 kHz 030.00 mV 030.00 mV 300 mV, 1 kHz 300.00 mV 300.00 mV Keysight U1251B and U1252B User’s and Service Guide...
  • Page 166 (for model U1251B) 2.0000 V 2.0000 V Turn the rotary switch to the Open Input terminal open oPEn oPEn (remove any test position leads and Short Plugs from the input terminal) Keysight U1251B and U1252B User’s and Service Guide...
  • Page 167 030.00 µA Press button to go to 300 µA,1 kHz 300.00 uA 300.00 µA µA mode 5000 µA 300 µA,1 kHz 0300.0 µA 0300.0 µA 3000 µA, 1 kHz 3000.0 µA 3000.0 µA Keysight U1251B and U1252B User’s and Service Guide...
  • Page 168 — To perform the adjustment, connect one end of the K-type thermocouple (with miniature TC connector on both ends) to the 5520A TC output, and the other end to the multimeter via a TC-to-banana adapter. Allow at least 1 hour for the multimeter to stabilize. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 169: Finishing The Adjustment

    Use the following procedure to read the calibration count from the front panel. 1 Press Adjustment Mode. The primary display shows the calibration count. 2 Take note of the count. 3 Press again to exit the calibration count mode. Keysight U1251B and U1252B User’s and Service Guide...

  • Page 170: Calibration Errors

    Calibration error: Serial number code invalid Calibration error: Calibration aborted Calibration error: Value out of range Calibration error: Signal measurement out of range Calibration error: Frequency out of range EEPROM write failure Keysight U1251B and U1252B User’s and Service Guide...

  • Page 171: Specifications

    Keysight U1251B and U1252B Handheld Digital Multimeter User’s and Service Guide Specifications For the specifications of the U1251B and U1252B Handheld Digital Multimeter, refer to the datasheet at http://literature.cdn.keysight.com/litweb/pdf/5989-5509EN.pdf.
  • Page 172 Specifications THIS PAGE HAS BEEN INTENTIONALLY LEFT BLANK. Keysight U1251B and U1252B User’s and Service Guide...
  • Page 173 This information is subject to change without notice. Always refer to the Keysight website for the latest revision. © Keysight Technologies 2009 – 2016 Edition 20, December 2, 2016 Printed in Malaysia *U1251-90036* U1251-90036 www.keysight.com...

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U1252b

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