Page 3 Standards and Technology to the extent allowed by N.I.S.T.’s calibration facility. Due to continuing product refinement and due to possible parts manufacturer change, Valhalla Scientific, Inc. reserves the rights to change any or all specifications without notice. Warranty Statement The warranty period for this instrument is stated on your invoice and packing list.
Page 4: Document History
Document History All Editions and Updates of this manual and their creation date are listed below. The first edition of the manual is 1. The edition number increases by 1 whenever the manual is revised. Updates, which are issued between editions, contain replacement pages to correct or add additional information to the current Edition of the manual.
Page 5: Safety Symbols
Safety Symbols Instruction manual symbol affixed to product. Indicates that the user must refer to the user manual for specific WARNING or CAUTION information to avoid personal injury or damage to the product. Warning - Risk of Electrical Shock. Procedure, Practice, Procedure, Practice, or Condition...
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 Valhalla Scientific for service and repair to ensure that safety features are maintained.
Page 8: Table Of Contents
HLC Relay Terminal ......................3-9 RS-232 Connector......................3-10 ..........................3-11 PPLYING OWER ......................3-11 OWER EFAULT ETTINGS 4300C ....................3-12 ONNECTING A OAD TO THE ....................3-14 AKING TANDARD EASUREMENTS Setting the Range......................3-14 Test Current ........................3-14 Charging Inductor Mode ....................3-15 Cable Disconnect Status Indicators ................
Page 9 ETAILED ESCRIPTIONS OF PERATIONS IEEE A ......................... 6-7 ETTING THE DDRESS ........................ 6-8 EMOTE AND OCAL TATES Local State........................6-8 Remote State ........................6-8 ........................ 6-8 EADING THE ISPLAY 4300C C GPIB ...................... 6-10 OMMAND ET FOR Voltage Range....................... 6-10...
Page 10 Configuration Status Query ..................6-13 RS-232 I .......................... 6-15 NTERFACE CONNECTING THE 4300C VIA RS232 INTERFACE ................. 6-15 The RS232 interface capabilities: .................. 6-15 Notes for RS232 installation ..................6-15 Connecting to a Computer .................... 6-16 Checking Connections ....................6-16 INPUT AND OUTPUT QUEUE ......................
Page 11 (DWG#: 834U-071) PG 2 of 3 ..................12-3 (DWG#: 834U-071) PG 3 of 3 ..................12-4 4300C M ..................... 12-5 OARD CHEMATICS (DWG#: 4300C-070) PG 1 of 2 ..................12-5 (DWG#: 4300C-070) PG 2 of 2 ..................12-6 4300C D ....................12-7 ISPLAY OARD CHEMATICS (DWG#: 4300C-071) PG 1 of 2 ..................
Page 12 Figure 12 - Binding Post ........................ 3-6 Figure 13 – Banana Plugs to Binding Post ..................3-7 Figure 14 - 4300C Rear Panel ......................3-8 Figure 15 – HI-LO Comparator Relay Pins ..................3-9 Figure 16 – 9 Pin RS-232 Connector .................... 3-10 Figure 17 –...
Page 13 xiii...
Page 14: Chapter 1 Inspection & Installation
The Model 4300C is a unique instrument capable of handling even the toughest resistance measurement applications. The 4300C is designed to measure the low resistance of such items as coils, transformers, ballasts, heater elements, etc. Some features of the 4300C that give it an edge over competitive products are: •...
Page 15: Initial Inspection
Chapter 2, notify the carrier's agent and the nearest Valhalla Sales Office. Retain the shipping carton for the carrier's inspection. DO NOT return equipment to Valhalla Scientific, Inc. or any of its sales offices prior to obtaining authorization to do so.
Page 16: Setting The Line Voltage
Chapter 1 – Inspection & Installation ETTING THE OLTAGE The line voltage selection is preconfigured according to the country to which it is shipped or as specified by the customer. To change this setting, follow the steps below: 1. Remove the power cord from the instrument. 2.
Page 17: Rack Mounting
4300C User Manual OUNTING Optional brackets are available for mounting the ohmmeter in a standard 19" equipment rack. The rack mount kit consists of two brackets plus 4 flat head screws. The brackets are easily installed on the front end of each side rail (see Figure 2).
Page 18: Safety Precautions
Any discontinuity in the ground lead may render the unit unsafe for use! The Model 4300C utilizes forced air cooling of the internal components. This operates continuously and care must be taken to ensure that the intake and exhaust ports remain clear.
Page 19 4300C User Manual...
Page 20: Standard Measurement Mode Specifications
PECIFICATIONS This section contains accuracy and operational specifications for the Model 4300C. The accuracy specifications are valid for a period of one year from the date of calibration at a temperature of 22°C to 28°C. Outside this range, the temperature coefficient specification applies.
Page 21: General Specifications
4300C User Manual ENERAL PECIFICATIONS Display: ....................... Multi Section VFD 140px x 32px Overload Indication: ..................Display flashes “OVERLOAD” Terminal Configuration: ..................... Four-wire Kelvin ADC Conversion Rate: .................... 45 conversions / second Display Update: ........ 5 user selections (100msec, 200msec, 300msec, 400msec, 500msec) Maximum Kick-Back Protection: ..............
Page 22: Chapter 3 Getting Started
4300C RONT ANEL The front panel of the 4300C can be broken down into nine parts. Figure 3 depicts the regions indicated by their name. On/Off Switch Figure 3 - Front Panel Layout...
Page 23: Display
The display is also used to prompt the user with alerts and messages Range Selection The 4300C has 3 voltage settings and 6 current ranges. The combination of the two result in 16 possible resistance measurement ranges. (See table 3).
Page 24: Test Current Key
Chapter 3 – Getting Started Within a voltage setting there are six possible Ohms Ranges. The two keys labeled Ω Range are used switch between the ranges. The  key is used to increase the range and the  key is used to decrease the range. As the Ohms range increases, the current range decreases and vice versa.
Page 25: Table 4 - Function/Numerical Keys Description
” key is used to set and/or view display update rate and PDATE Update intensity. The “HLC” key is used to enable or disable the 4300C’s internal “Multi- Range Dual Limit Comparator. Also used to set and/or view the limits used. The “A .”...
Page 26: Tc Mode Key And Sensor Receptacle
The red LED, labeled “XHI”, is on if the measured resistance value is greater than the upper limit. The Omni Compensator is an optional accessory to the 4300C. See Chapter 4-3 for more detail. See Chapter 4-8 for detail on how to set the Hi-Lo limits.
Page 27: Cable Disconnect Status Indicators
Test Current is on, regardless of the load. The Charging Inductor mode LED indicates when the standard current source compliance voltage of 7V is exceeded. In this situation the 4300C provides a booster shot in excess of 20V to reduce the settling time when a large inductive load is being measured.
Page 28: Figure 13 - Banana Plugs To Binding Post
In many applications the contact resistance can exceed the value of the load by several orders of magnitude. The 4300C bypasses this potential error source by providing two terminals of constant current and an additional two terminals for high impedance voltage sensing.
Page 29: Rear Panel
4300C User Manual ANEL The rear panel of the 4300C may vary from unit to unit according to the optional features installed. This section of the manual refers to the standard model without any optional features or modifications. If the...
Page 30: Fuse Holder
Chapter 3 – Getting Started Fuse Holder The line power fuse must match the line voltage selection as follows: • 105-125VAC – 3A SLO-BLO • 210-250VAC – 1.5A SLO-BLO The fuse holder is located on the rear panel (see Figure 1). To install a fuse, first disconnect the Ohmmeter’s power cord.
Page 31: Rs-232 Connector
4300C User Manual RS-232 Connector The RS-232 serial interfacing is done through the 9 pin female D-Sub connector located on the rear panel of the instrument. Knowledge of the specific pin functions of the serial connector may be necessary for certain applications;...
Page 32: Applying Power
Chapter 3 – Getting Started PPLYING OWER Before applying power, please refer to Chapter 1 for safety precisions. Turn on the ohmmeter by placing the front panel power switch in the ON position. If the ohmmeter does not turn on, verify that the instrument is connected to the power line.
Page 33: Connecting A Load To The 4300C
The next step in using the ohmmeter is to connect to a load. Valhalla Scientific, Inc. offers a number of different test leads that can be used with the Model 4300C and other Valhalla ohmmeter models (see Chapter 5 for a list of available test leads).
Page 34: Figure 20 - Dual
Chapter 3 – Getting Started For flat surfaces, you can Figure 19 – Surface Type clips between different spring loaded surface probes. If this is your choice of leads, simply press one probe against one side of the surface of your load, making sure that the surface of the probe is in full contact with the...
Page 35: Taking Standard Measurements
Setting the Range instrument. The 4300C has 3 voltage settings and 6 current ranges. The combination of the two result in 16 possible resistance measurement ranges. (See table 7). Table 7 –...
Page 36: Charging Inductor Mode
Current On, or with the UNSAFE LED lit. In some extreme applications if leads are removed or pulled loose before the SAFE LED is lit, damage may occur to the 4300C and/or injury to the operator! The UNSAFE LED is also illuminated whenever a test current of .1A or greater is selected and the Test Current is turned ON, regardless of the load.
Page 37 4300C User Manual 3-16...
Page 38: Chapter 4 Measurement Modes And Functions
In many applications the contact resistance can exceed the value of the load by several orders of magnitude. The 4300C bypasses this potential error source by providing two terminals of constant current and an additional two terminals for high impedance voltage measurement.
Page 39 Once the temperature coefficient and the temperature reference are set, the instrument’s task is to measure the load resistance and the ambient temperature. After all the variables are determined, the 4300C automatically calculates the compensated resister value. Here is an example of the equation.
Page 40: Omni Compensator
This item does not come standard with the ohmmeter, and must be purchased separately. If the 4300C and the Omni Compensator are purchased at the same time, the pair will be calibrated together. Each instrument should have a dedicated sensor. The user cannot interchange sensors between different ohmmeters without prior calibration.
Page 41: Table 8 – Tcm Setup Ref. Table
4300C User Manual Table 8 – Temperature Temperature Material Configuration TCM Setup Ref. Table Coefficient Reference CU20 20°C Copper 3931ppmΩ/°C CU20 25°C AL20 20°C Aluminum 4030ppmΩ/°C AL25 25°C AG20 20°C Gold 3000ppmΩ/°C AG25 25°C The following procedure illustrates how to select one of these configurations and how to setup a customized configuration.
Page 42: Tcc - Temperature Compensator Calibration
• The screen will display a brief message and the instrument TCC – Temperature Compensator Calibration will return to the standard measurement mode. This procedure is used to match a 4300C with its Omni Compensator. • Verify that the instrument is in a temperature controlled area.
Page 43: Hlc" - H I -L O Comparator Mode
HLC mode. If, for example, the resistors to be inspected and tested are 1 KΩ ± 0.1%, the 4300C would be set on the 2kΩ range; the upper limit would be set at 1.0010kΩ, and the lower limit to 0.9990kΩ.
Page 44: Setting The Limits
Chapter 4 – Measurement Modes and Functions Table 9 – HLC Truth Table HLC State HLC Result LL≤Ω≤UL OPEN CLOSED OPEN Ω<LL CLOSED OPEN OPEN UL<Ω OPEN OPEN CLOSED OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN Setting the Limits Each range has a different set of limits that can be programmed by the user.
Page 45: Hlc On
4300C User Manual HLC ON To start working with the HLC mode, simply select the correct range for your load and press the “HLC”. The screen will briefly display “HLC ON”. The instrument will also perform an LED check-sequence. Make sure that all three of the HLC LEDs illuminate.
Page 46: Setting The Display Update Rate And Intensity
Chapter 4 – Measurement Modes and Functions Setting the Display Update Rate and Intensity To change the display update rate and the display intensity: • Press “F . + U ” PDATE • Select an update rate using the numerical keys from 1 thru 5 and press “E ”.
Page 47: Run /Hold Function
4300C User Manual UNCTION The Run/Hold function of the 4300C can be configured three different ways: RUN/HOLD Figure 27 – Display Function Window • When configured for Run/Hold, pressing the “R /Hold” key will freeze the readings on the display.
Page 48: Print /Log Function
Chapter 4 – Measurement Modes and Functions RINT UNCTION The Print/Log function allows the user to receive the measurements through the instrument’s RS-232 or USB interface. A thermal printer/labeler or the HyperTerminal of a PC can be used to capture the readings.
Page 49: Configuring The Print Button Function
4300C User Manual Configuring the Print button function To configure the Print/Log function: • Press “F . + P ” RINT • Select one of the three options by pressing keys 1, 2, or 3 and press “E ”. NTER •...
Page 50: View Function
Chapter 4 – Measurement Modes and Functions UNCTION The View function allows the user to view how the instrument’s functions are configured. This function is easy to use and is very useful especially Using the View function for HLC and TCM users. Press “V ”...
Page 51 4300C User Manual 4-14...
Page 52: Options
Option RX-3: Rack Mount Adapter compensate for temperature variations when testing any material. The 4300C μ-ohmmeters may be mounted in a standard 19" equipment rack using a set of optional rack ears. Option RX-3 comes with all the necessary hardware for installation and mounting. An assembly diagram on how to install to rack ears on to the instrument can be found in Chapter 1.
Page 53: Test Leads
4300C User Manual EADS This section details the different test lead sets and connectors available for use with the 4300C μ-ohmmeters. All cables and test leads are Alligator Clip Type Leads manufactured by Valhalla Scientific Inc. and are tested before shipping.
Page 54: Needle Type Probes
Chapter 5 – Optional Features and Accessories Needle Type Probes Option MP-1: Kelvin Micro-Probes Option "MP-1" is a 48-inch shielded 4-wire Kelvin cable set with a 1A test current capacity employing a set of Kelvin Micro- Probes. The probes are equipped with spring-loaded stainless steel tips with 0.05"...
Page 55: Surface Probes
4300C User Manual Surface Probes Option MP-4: Surface Probes These probes permit rapid, repeatable bonding testing on a variety of screened or flat surfaces. Test current is evenly distributed through the probe base while sensing is accomplished via a spring loaded center contact.
Page 56: Chapter 6 Remote Operations
Chapter 6 EMOTE PERATIONS IEEE I NTERFACE IEEE S URPOSE OF TANDARD The purpose of the IEEE Standard 488 is to allow for interconnection of programmable instruments with minimum engineering. The intent is to remove the need for adapters and the numerous types of patching cables often encountered with other forms of interfaces.
Page 57: Definitions
4300C User Manual EFINITIONS Listed below are definitions of the terms used to describe the IEEE-488 interface: Bus: A data link which is usually a set of several parallel wires within a multi-wire cable. Bi-Directional Bus: A "highway" used for two-way communication, with input and output data being carried on the same lines.
Page 58: Bus Restrictions
The other devices may be listeners (only able to receive data) or talkers (only able to send data), or both. The model 4300C is capable of talking and listening. The controller may address other devices and command them to listen or talk.
Page 59: Detailed Descriptions Of Bus Operations
4300C User Manual ETAILED ESCRIPTIONS OF PERATIONS The five management wires are described as follows: ATN: Asserted by the controller whenever an address or a command is present on the bus. EOI: May be asserted by the controller or any talker. With ATN true, EOI indicates that the controller is polling devices.
Page 60: Table 12 - Ascii Character Codes
This handshake protocol assures that data on the bus is transferred at the speed of the slowest device on the bus. Data is sent in 8-bit bytes on the DIO wires, usually (as in the 4300C) using the ISO-7 standard ASCII characters. Table 12 lists each ASCII character and the bus messages applicable to each.
Page 61 4300C User Manual The primary command group is further divided into four subgroups as follows: 1. Addressed Command Group - applied only to addressed devices. 2. Universal Command Group - applied to all devices. 3. Listen Address Group - set of device listen addresses.
Page 62: Setting The Ieee Address
The IEEE "address" is the method by which the system controller distinguishes one device on the bus from another. The address of the 4300C is determined by the setting of a binary-weighted switch on the rear of the instrument. Here are two examples to help you set the address.
Page 63: Remote And Local States
The 4300C does not require that a query or any other command be issued in order to retrieve it. Also, the 4300C does not need to be in REMOTE in order for the display to be read. Retrieving the data will clear the reading buffer.
Page 64 The result is returned in scientific notation, in ohms. As an example, assume that the 4300C is in the 2V and .1mA ranges and the front panel display indicates "10567" which is 10,567Ω. The program above is executed. The 4300C responds with the following number (contained in A$): +1.0567E+4...
Page 65: 4300C Command Set For Gpib
   The result of this program is to set the 4300C to the 2V, 100mA ranges and turn on the test current. The controller waits for 2 seconds (for settling), then Voltage Range retrieves the measured value. The 4300C is then returned to local mode.
Page 66: Test Current Range
4300C. Q0 - 4300C will not assert SRQ (default) Q1 - 4300C will assert SRQ if it receives a command that it does not understand If the SRQ line is asserted, the controller should then perform a serial poll to determine which device requires service.
Page 67: Output Data Terminator
The "D" command determines the type and quantity of terminators that will be used to signal the end of any data that the 4300C returns to the controller. This includes measured resistance data as well as the response to the "configuration status"...
Page 68: Configuration Status Query
Upon receiving the code E the 4300C will place into its output buffer a "configuration status word". The status word is made available for the next read by the controller.
Page 69: Table 13 - Ieee
Test Current ON w/EOI Error 10mA 100mA w/EOI Selects hold mode / Triggers single reading Selects continuous reading mode Selects normal mode (TCM OFF) Selects TCM mode ON Returns 4300C to Local Configuration Status Word Query ( Q?V?I?SND?C?UHF ) 6-14...
Page 70: Interface
CONNECTING THE 4300C VIA RS232 INTERFACE The RS232 interface provides a point-to-point connection between two items of equipment such as a computer and the 4300C. There are some parameters you need to set on both sides. Once you have set these parameters, you can control the 4300C through the RS232 interface.
Page 71: Connecting To A Computer
Should return the Manufacturer, model number, serial number and firmware version in the following format: VALHALLA SCIENTIFIC 4300C,1.81,0" If you do not receive a proper response from the 4300C, please check if the power is on, and all cable connections are active. 6-16...
Page 72: Input And Output Queue
Entering Commands to judge message terminator. The standards that govern the command set for the 4300C allow for a certain amount of flexibility when you enter commands. The 4300C does not adhere to any friendly listening standards so the commands and Command Characters queries must be typed as specified.
Page 73: Details Of Command Reference
4300C User Manual DETAILS OF COMMAND REFERENCE Each command in this chapter will give a detailed description. The examples of each command will be provided and what query form might return. Syntax and return values for each are explained in the function header.
Page 74 Chapter 6 – Remote Operations (RS-232 Interface) :SYST:ERR? QUERY Sends the System Error value to the remote host. Cleared with *CLS<crlf> Syntax: :SYST:ERR? Example: :SYST:ERR?<crlf> Response: 1F<crlf> Power-on default = 0 BCD COMMAND Selects BCD mode on or off Syntax: BCD <ON or OFF>...
Page 75 4300C User Manual CALDATE QUERY Request the last calibration date and technician initials. Syntax: CALDATE? Response: "00-00-04 VSI" Power-on default = "00-00-00 VS####" *CLS COMMAND Sets buffers to power on default. Syntax: *CLS<crlf> CNFG COMMAND Turns on and off system configuration items. Alarms, key beeps, other features.
Page 76 Chapter 6 – Remote Operations (RS-232 Interface) FAULT COMMAND Sets an alarm fault to watch the system react. Syntax: FAULT <Hexadecimal number> FAULT_ALARM_NO_FAULT FAULT_ALARM_OVER_TEMP Internal temperature too high FAULT_ALARM_CAL_LIMIT Input level for calibration exceeded limit FAULT_ALARM_TCM Input level for TCM calibration exceeded limits FAULT_ALARM_CMD_CHAR Unprintable characters received / cmd too long FAULT_TXBUF_SPACE...
Page 77 4300C User Manual HLC COMMAND Selects HLC mode on or off Syntax: HLC <ON or OFF> Example: HLC ON<crlf> HLC?<crlf> ON<crlf> Power-on default = OFF Note: HLC mode on puts the logic level HLC relays on the rear panel connector and the ranges on the relays outputs.
Page 78 Chapter 6 – Remote Operations (RS-232 Interface) HLCHI? QUERY Reads the Hi-Lo Comparator high value from RAM for range. Syntax: HLCHI? Response: Floating (fixed) point Ohm value for current range. "1.0000" for 1Ω in the 2Ω range and 100.00 for 100mΩ in the 200mΩ range. This command reads the value from RAM memory only.
Page 79 4300C User Manual *IDN? QUERY Returns the IEEE or RS-232 identification string from non-volatile. Syntax: *IDN?<crlf> Response: ID string "VALHALLA SCIENTIFIC 4300C,1.01G,0" Example: *IDN?<crlf> "VALHALLA SCIENTIFIC 4300C,1.01G,0"<crlf> ID_STRING "VALHALLA SCIENTIFIC" VERSION "1.01G" MODEL "4300C" HARDWARE_VER "0" OPTION_STRING "Option(s) : GPIB(IEEE488.2)"...
Page 80 Chapter 6 – Remote Operations (RS-232 Interface) KEY COMMAND Presses a key from the interface, use for macros when the command you desire is not listed here. Syntax: KEY <key number> Response: <crlf> (only after the key has been processed) Key number = 0 - 24 KEY_NO_KEY KEY_1...
Page 81 4300C User Manual KEY? QUERY Returns the decimal number of the key last key processed by the state machine. This query returns any key in the remote mode even if the key is locked out by remote mode, i.e. KEY_LOCAL is not locked out.
Page 82 Chapter 6 – Remote Operations (RS-232 Interface) LOCAL COMMAND Returns meter to local mode, remote LED off, Goto Local. Syntax: LOCAL Returns: <crlf> Power-on default = LOCAL mode Notes: REMOTE mode is selected when the meter receives a valid character (not <crlf>. Once selected, all keys are disabled and will not be scanned.
Page 83 4300C User Manual OHMS? QUERY Responds with reading from the front panel display and causes an immediate update of the conversion so repeated query requests gets most accurate data. Send range command or AUTO prior to sending this to get the scaling factor.
Page 84 Chapter 6 – Remote Operations (RS-232 Interface) CURRENT RANGE COMMAND Selects a current range Syntax: IRANGE <range number> Range number = 1 – 6 1 = 10A 4 = 10mA 2 = 1A 5 = 1mA 3 = 0.1A 6 = 0.1mA RANGE? QUERY Returns the selected range.
Page 85 4300C User Manual CURRENT RANGE COMMANDS Returns the selected current range. Syntax: IRANGE? Response: Range number = 1 - 6 1 = 10A 4 = 10mA 2 = 1A 5 = 1mA 3 = 0.1A 6 = 0.1mA TEST CURRENT COMMAND Selects TEST CURRENT on or off Syntax: TCURRENT <ON or OFF>...
Page 86 Chapter 6 – Remote Operations (RS-232 Interface) RDNG? QUERY Responds with reading from the device in engineering notation. Query function also uses an immediate update of the conversion so repeated query requests gets the most accurate data. Syntax: RDNG? Example: RDNG?<crlf>...
Page 87 4300C User Manual *RST COMMAND Sets buffers to power on default. Syntax: *RST<crlf> Response: <crlf> Remote command buffer, Serial I/O, history, statistics, stability SAVSETUP COMMAND Stores current RAM setup data in NV RAM. Syntax: SAVSETUP<crlf> SAVSETUP? QUERY Refreshes the current Setup from NV-RAM and then sends it to the remote port.
Page 88 Chapter 6 – Remote Operations (RS-232 Interface) *STB? QUERY Returns the command status byte. Syntax: *STB? Response: Command status number = 0 - 0xFF Example: *STB?<crlf> 01<crlf> Fragment: TCM ON<crlf> *STB?<crlf> TCM AFF<crlf> **STB?<crlf> (returns * ERROR) 03<crlf> TCM?<crlf> ON<crlf> 0 = CMD_LAST_COMPLETE 1 = CMD_UNKNOWN 2 = CMD_MISSING_PARAM...
Page 89 4300C User Manual TCM COMMAND Selects TCM mode on or off Syntax: TCM <ON or OFF> Example: TCM ON<crlf> TCM?<crlf> ON<crlf> Power-on default = OFF TCM QUERY Responds with TCM mode on or off Syntax: TCM? Example: TCM?<crlf> ON<crlf> Response: <"ON"...
Page 90: Bcd Interface
Signals are also provided for range information, and overload. A run/hold line is also provided to halt the 4300C. The signals are TTL compatible ( 0 ≤ .8V , and 1≥ 2.4V ) and will drive 1 LS TTL load.
Page 91: Ranges
4300C User Manual Ranges This is a BCD exponent which indicates the present resistance range as follows: Table 16 – BCD Range PIN # Function Range Data 2mΩ 20mΩ 200mΩ 2Ω 20Ω 200Ω 2kΩ Overload – Pin 12 20kΩ This pin is set to logic 1 when the data on the lines above is an overload Pin assignment indication.
Page 92: Chapter 7 Theory Of Operations
PERATIONS The information contained in this section describes the theory of operation behind the Valhalla Model 4300C Digital Micro-Ohmmeter. The theory is divided into two sections. The first is a general description referring to the block diagrams of Figure 39. The second section is a detailed description referring to the schematics and diagrams at the back of this manual.
Page 93: General Description Of Circuits
4300C User Manual ENERAL ESCRIPTION OF IRCUITS This section describes the general function of each section of the Model 4300C. The ohmmeter may be divided into four separate parts: Figure 39 – 4300C Block Diagram...
Page 94 Chapter 7 – Theory of Operations o 4300C Main Board (4300C-700) – This portion of the ohmmeter contains the power supply and the constant current source. • Power Supply – This section converts the AC line power into the DC levels necessary to power the ohmmeter’s circuitry.
Page 95 Display – This is the visual interface to the user. The display receives its data directly from the micro-controller. o Keypad Board (4300C-701) – This section of the ohmmeter contains the keypad and the LED indicators for the TCM and HLC function.
Page 96: Detailed
IRCUIT ESCRIPTIONS This section describes in detail the operation of the main circuits of the Model 4300C. The reference designators used in this section refer to the Current Source drawings included at the back of this manual. The operation of the Current Source is described in the following paragraphs.
Page 97: Output Stage
4300C User Manual Output Stage The output stage composed of TR101, TR102, R101, R102, R126 and RLB- 1 provides current gain capable of sourcing 10 amps. Base drive for transistors TR101 and TR102 is provided by the error amplifier. Resistors R101 and R102 equalize the emitter currents in the two output devices.
Page 98: Micro-Controller Board
Chapter 7 – Theory of Operations Micro-Controller Board Complete circuitry is shown on schematic 834u-071. Figure 41 – µ-Controller Block Diagram Micro-Controller The micro-controller executes the analog to digital conversion on the voltage across the load. Also all other processes, such as range selection, HLC relay switching, LEDs activation and so on.
Page 99: 2.5V Reference
The power supplies are also one of the first things that should be checked. As it is not possible to anticipate all failure modes of the 4300C, servicing personnel should become familiar with this chapter to gain a complete...
Page 100: Component Replacement
Component Replacement If the problem has been identified as a faulty component, the accuracy of the 4300C can be maintained only if the following precautions are taken: • Use only the specified component or its exact equivalent. Spare parts can be ordered from your nearest Valhalla Scientific Service...
Page 101 4300C User Manual 7-10...
Page 102: Chapter 8 Routine Maintenance
30 minutes with the covers in place. EQUIRED QUIPMENT The following equipment is required to perform calibration of the 4300C: 1) Precision resistors within ±0.005%, the following values: 0.1Ω 1Ω...
Page 103: 4300C Calibration Procedure
The source calibration is performed by adjusting six potentiometers located on the 4300C main board. All three calibrations must be performed for a complete Sense Calibration calibration of the 4300C.
Page 104: Current Source Calibration
Cal (see Chapter 4). The following procedure should be performed when calibrating the current source section of the 4300C. In all steps the current source is calibrated to the internal voltmeter therefore the sense calibration, described earlier in the chapter, should be performed before proceeding.
Page 105: 10 Amp Adjustment
10 Amp Adjustment Connect the 0.1Ω standard resistor to the 4300C using four-wire connections. Select the 2V and 10A ranges on the 4300C. Adjust RV102 for a reading of 100.00mΩ. Allow extra time for settling in this range. Keep the cover on as much as possible to ensure proper cooling of components.
Page 106: Tcm Calibration
Chapter 8 – Routine Maintenance TCM Calibration I. Remove the top cover of instrument. IX. Verify that the Omni Compensator (Temp. Sensor) is not connected to the ohmmeter. Press “E ” to continue. NTER The instrument will perform the TCM Zero Cal. The screen will display the following information: X.
Page 107: Figure 42 - Drawing № 4300C-700
4300C User Manual Figure 42 – Drawing № 4300C-700...
Page 108: Chapter 9 Special Procedures
When measuring highly inductive loads the settling time of the ohmmeter is determined by the compliance voltage of the current source. Typically, the compliance voltage of a 4300C in the Charging Inductor mode is in excess of 20V. Thus, with an inductor of 1000 Henries (an extremely large transformer) the unit will take approximately 10 minutes to settle.
Page 109: Noisy Readings
EADINGS When measuring very low resistances of highly inductive loads, care should be taken to reduce 60Hz pickup at the input to the 4300C. The noise pickup is caused by the very high impedance of the load at 60Hz given by the formula:...
Page 110: Disconnecting The Cables
Using the "Flyback Diode" in the 4300C. As discussed in Chapter 7, the 4300C has an internal diode which can sink the excess current being discharged from the inductor. Therefore turning off the test current and/or reducing the 4300C's current range from the original test current to a low value (less than 10mA) will automatically discharge the inductor into the Flyback diode.
Page 111 R =Total resistance of cables, switch and inductor (in ohms) In a typical application R might be approximately 1 milliohm (.001Ω) and L might be 1000 Henries. If the 10 amp range of the 4300C was used to measure the inductor, 7,000,000 seconds are required (11½ weeks) to discharge it.

Valhalla Scientific 4300C Operation Manual

Chapter 1 Inspection & Installation

Chapter 10 Addendums

Chapter 11 Parts List

Chapter 12 Schematics

Chapter 2 Specifications

Chapter 3 Getting Started

Chapter 4 Measurement Modes and Functions

Chapter 5 Optional Features and Accessories

Chapter 6 Remote Operations

Chapter 7 Theory of Operations

Chapter 8 Routine Maintenance

Chapter 9 Special Procedures

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