Related Manuals for Water Analytics AquaMetrix AM-2250
Summary of Contents for Water Analytics AquaMetrix AM-2250
- Page 1 AM-2250 / AM-2250TX /AM-2251 Multi-Parameter Controller / Transmitter Installation and Operation Manual 2250-series Operating Manual rev 2.0...
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Page 2: Table Of Contents
Contents Introduction ............................5 Third in a Long History of Controllers ..................... 5 Differences between the AM-2250, AM-2250TX and AM-2251 ............ 5 Specifications ............................6 AM-2250 Technical specs ....................... 6 AM-2250TX Technical specs ......................7 AM-2251 Technical specs ....................... 8 Setup ............................... - Page 3 5.2.1 About ORP Calibration ......................28 5.2.2 ORP Calibration ........................28 5.2.3 Temperature ......................... 29 Conductivity ..........................29 5.3.1 About Conductivity Calibration .................... 30 5.3.2 Manual Conductivity Calibration or Wet Calibration ............30 5.3.3 Cell Constant ......................... 31 5.3.4 Temperature ......................... 31 5.3.5 Dry Conductivity Calibration (AM-2251) ................
- Page 4 Run Mode ............................. 47 Display Features ........................... 47 Maintenance ..........................47 Diagnostics ............................48 Calibration Data ..........................48 Sensor Output ..........................48 Factory Reset ..........................49 About ............................49 Preferences ............................50 Auto Return ..........................50 Damping ............................50 Backlight (AM-2250 and AM-2251) ....................50 2250-series Operating Manual rev 2.0...
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Page 5: Introduction
1 Introduction Third in a Long History of Controllers The AM-2250 multi-parameter controller is the third-generation controller built on the 30-year AquaMetrix legacy of building durable and easy-to-use controllers. Many of the 2200 controllers sold those three decades ago are still in use today in some of the most hostile environments found in industry. Orders continue to come in today for 2200 pH, ORP or conductivity models, years after they entered end- of-life status. -
Page 6: Specifications
2 Specifications AM-2250 Technical specs Probe Parameters Conductivity Flow 6-wire differential 6-wire differential 2-electrode with Pulse output: Sensor or b cell constants: Paddle-wheel combination combination from 0.01 to 100 Magnetic Flow Temperature Pt100 RTD, Pt1000 RTD, NTC 300Ω, NTC 3000Ω, NTC10k NTC Elements With Auto Detect Feature Sensor Input... -
Page 7: Am-2250Tx Technical Specs
AM-2250TX Technical specs Probe Parameters Conductivity Flow 6-wire differential 6-wire differential 2-electrode with Pulse output: Sensor or b cell constants: Paddle-wheel combination combination from 0.01 to 100 Magnetic Flow Temperature Pt100 RTD, Pt1000 RTD, NTC 300Ω, NTC 3000Ω, NTC10k NTC Elements With Auto Detect Feature Sensor Input... -
Page 8: Am-2251 Technical Specs
AM-2251 Technical specs Probe Parameters Conductivity 6-wire differential 6-wire differential Clark cell Sensor Inductive or combination or combination 2-electrodes Temperature Pt100 RTD, Pt1000 RTD, NTC 300Ω, NTC 3000Ω, NTC10k NTC Elements With Auto Detect Feature Sensor Input -600 to 600 mV -999 to 999 mV Cond: 0 to 9999 Ω... -
Page 9: Setup
3 Setup AC Power Connections (AM-2250 and AM-2251) Caution: This instrument uses 120 or 240 50/60Hz AC power. Opening the enclosure door exposes you to potentially hazardous line power voltage which may be present on the power and relay plugs. Always remove line power before working in this area. -
Page 10: Loop Power Connection (Am-2250Tx)
Loop power connection (AM-2250TX) The AM-2250TX is a low-power transmitter that has three options for being powered: 1. Most commonly it is loop powered by a PLC or the AquaMetrix 2300 web-enabled controller. The AM-2300 Web-enabled controller can power up to four AM-2250TX transmitters using its internal power supply. -
Page 11: Conduit Connection
3. The AM-2250TX can be used with a PLC or data logger without internal loop power. Connect the power supply in series, as shown on the right of Figure 3-5. The required power supply voltage will vary depending on the resistance in the PLC or recorder. Figure 3-6 shows the power needed as a function of the PLC loop resistance. -
Page 12: Mounting
Mounting All 2250 series controllers and transmitters can be mounted on a wall, panel or pipe. Figure 3-7 shows these three options. All hardware for wall and panel mounting is included. There are two optional kits that are available for sale: 1. -
Page 13: Connecting Probes
Connecting Probes As shown in Figure 3-8, the cover of the cover of the AM-2250 swings open to reveal a connector block for connecting probes. A label inside the controller identifies the terminals so reference to this manual is unnecessary. Note than connectors 1 and 2 are used for the 4-20 mA output (CH1) of the AM-2250 and AM-2251 controllers. -
Page 14: Analog (4-20 Ma) Outputs
Figure 3-10 AM-2251 sensor wiring All AquaMetrix pH and ORP sensors can be connected to any 2250-series analyzer. Table 1 lists the set of probes that connect to all three analyzers. Figure 3-11 Sensor compatibility chart Analog (4-20 mA) Outputs The AM-2250TX contains one 4-20 mA output that is isolated from sensor input. -
Page 15: Relays (Am-2250 And Am-2251)
Relays (AM-2250 and AM-2251) 3.7.1 Wiring relays The AM-2250 and AM-2251 contains three dry contact relays. For a resistive load they are rated 10A @ 120/240 VAC or 8A @ 30 VDC. For an inductive load they are rated 5A @ 120/240 VAC or 4A @30 VDC. Though these relays will work in most process control applications, we advise, for safety reasons, to use them as switches, i.e. -
Page 16: Probe Setup
4 Probe Setup When powering up the 2250 the first screen presents options for configuring sensors. Figure 4-1 Initial start-up screen 1. Use the ↑ ↓ buttons to scroll through the menu. → 2. Use the buttons to move the cursor left or right. 3. - Page 17 5. Type is either Combination or Differential. The 2250 will accept virtually any combination or differential sensor. Entering a probe as the wrong type will simply result in an artificial offset and may not cause any noticeable reading or error. Combination probes may consist of only two wires for the process and reference or four wires, which includes two leads for the temperature element.
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Page 18: Orp
As with pH probes all differential ORP probes and four-wire combination probes contain temperature elements. However, ORP values are NOT temperature compensated. The temperature value is only for informational purposes. 1. From the top-level menu select Setup and press the Enter key. -
Page 19: Conductivity
6. Select the preferred units of temperature (Temp Unit): 7. Press to confirm that controller displays mV units and reasonable temperature values. Conductivity 1. From the top-level menu select Setup and press the Enter key. 2. Press Probe Selection to choose the probe type, Conductivity, and press the Enter key. - Page 20 All conductivity sensors can measure conductivity values outside their ideal measurement range but the accuracy of the readings will suffer due mainly to the non-linear relationship between the reading and the conductivity value. 5. Choose Temperature Element. Conductivity readings are strongly influenced by temperature so nearly all conductivity probes have temperature elements.
- Page 21 MΩ-cm. For very pure water many workers prefer to report resistivity units in place of conductivity units. One is the inverse of the other. Ultrapure water has a resistivity of 18.8 MΩ- cm (0.055 µS/cm). (Its finite resistance is the result of H and OH ions.) (mg/l).
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Page 22: Dissolved Oxygen (Am-2251)
Dissolved Oxygen (AM-2251) 1. Scroll down the top-level menu to select Setup and press the Enter key. 2. Press Probe Selection and choose the probe type, DO. 3. This selection automatically brings up the next menu that defines the configuration of the DO sensor. -
Page 23: Flow (Am-2250 And Am-2250Tx)
The AM-2251 controller contains a pressure sensor that measure atmospheric pressure so manual entry is not required. Salinity also affect the concentrations of oxygen in water. The amount of oxygen that can dissolve in water decreases as salinity increase. Seawater solubility is about 20% less compared to fresh water. -
Page 24: Totalizer Reset
6. Press to confirm that the selected flow unit displays correctly. Most flow sensors don’t have a temperature device, so the total flow value replaces the usual temperature value. 4.5.1 Totalizer Reset. There are two ways to reset the totalizer. 1. -
Page 25: About Ph Calibration
5.1.1 About pH Calibration Most pH analyzers allow the user to calibrate a probe with only two points, using two of three standard calibration solutions: pH 4, 7 and 10. For two-point calibration use the two standards that are closest to your expected process values. - Page 26 There are several reasons why this can happen: 1. The offset of the probe is greater than 59 mV. 2. The buffer is non-standard (i.e. neither 4, 7 or 10). 3. The buffer has aged and is no longer at its nominal pH value. To initiate auto calibration: 1.
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Page 27: 3-Point Calibration
5.1.2.2 Manual Calibration As explained above manual calibration can be used if the probe has a very large offset, has low efficiency or is being calibrated with non-standard buffer solutions. 1. Select Manual Calibration 2. Place the probe in the first buffer. As opposed to auto calibration, it is okay to press Enter without waiting for the probe output to settle down. -
Page 28: Orp Calibration
down prior to pressing Enter. The next screen allows you to change the temperature reading to match the actual temperature. Press Enter when done or Menu to go back to the top menu. ORP Calibration 5.2.1 About ORP Calibration ORP is a unique water quality parameter. For all other parameters a voltage, current or other electrical change corresponds to a value of the parameter and calibration determine that relationship. -
Page 29: Temperature
3. Observe the probe output reading and, when it has settled down, press Enter. 4. Adjust the value displayed in the next screen until it matches that of the calibration standard. Note that ORP standards can be negative so be careful to select the correct + or - sign. 5. -
Page 30: About Conductivity Calibration
5.3.1 About Conductivity Calibration As with ORP calibration there are no recognized standard calibration standards so there is no auto calibration option. Also, as with ORP, conductivity calibration standards are not buffered and can change. Stability of the conductivity standard is only a problem for standards of very low conductivity, where introduction of impurities in the solution can induce large changes in conductivity. -
Page 31: Cell Constant
3. Immerse the probe in the first (or only) calibration standard. Press Enter. 4. The display will show the current conductivity reading. Adjust the conductivity reading to match the actual conductivity value of the standard. 5. Repeat for additional standards if there are any. 6. -
Page 32: Dry Conductivity Calibration (Am-2251)
5.3.5 Dry Conductivity Calibration (AM-2251) In a case of toroidal (inductive) conductivity sensor there is a coefficient that characterizes the relationship between the voltage of the drive coil and the voltage of the receive coil—the transfer ratio. The transfer ratio typically varies from one sensor to another even for the same model. Some probes arrive with a transfer ratio already measured at the factory. -
Page 33: Zero Offset Calibration (Am-2251)
5.3.6 Zero Offset Calibration (AM-2251) Zero offset calibration is only necessary for conductivity values less than 50 µS/cm. The zero offset should remain stable over time, so its calibration needs to be done only once if no changes are made to the sensor, controller or installation environment. -
Page 34: About Do Calibration
5.4.1 About DO calibration For most applications single point DO calibration is sufficient. As with conductivity calibration a second point assumes zero signal at zero DO. DO sensors respond neither to concentration nor %-saturation. They respond to oxygen gas partial pressure (the 21% of the atmosphere comprised of oxygen) and, though it may seem counterintuitive, the gas pressure in ambient air is the same as that in fully saturated water. -
Page 35: Zero Offset Calibration
4. Press Enter to accept the calibration or Back to discard it. 5.4.3 Zero Offset Calibration The factory default value for zero D.O. is 0 nA offset. In order to calibrate the actual offset, a fresh 0%-sat solution must be prepared. Do not stir it as this may force oxygen absorption. 1. -
Page 36: Flow (Am-2250 And Am-2250Tx)
2. The screen displays the current temperature reading. Make sure the temperature reading has settled down. Keep in mind that most temperature elements in pH probes are encapsulated inside the probe, which results in a temperature lag of several minutes for the element to equilibrate with the temperature of the solution. -
Page 37: Output
6 Output The AM-2250TX transmitter has one 4-20mA output with optional PID. The AM-2250 and AM-2251 has two output modes: 1. Three dry contact relays 2. Two isolated 4-20 mA current outputs (Channel 1 with optional PID) When the 2250 is used for process control then one to three of the relays are configured. When the 2250 is used in conjunction with PLC’s or SCADA systems then the 4-20 mA outputs are configured. - Page 38 For rising and falling setpoint there is a second setpoint at which the relay deactivates. The gap between the set-point and the deactivation point is the dead-band. For instance, if you may be controlling a process whose pH naturally rises. If you want to lower the pH when it reaches pH 9 then set the relay set-point to 9.
- Page 39 5. Confirm by pressing Enter. 6.1.1.2 Falling Process The configuration process is identical to rising process (section 6.1.1.1) except that the on setpoint must be lower than the off setpoint. As stated above, a relay cannot be set for a rising process AND a falling process.
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Page 40: Cycle On/Off
4. If your lower value is higher than your lower value the following warning message appears. 5. Confirm by pressing Enter. 6.1.2 Cycle On/Off The cycle on/off parameter is very useful for preventing overshoot of a process controlling action— usually the dispensing of a chemical. If the response time of the process to the added chemical is slow compared to the rate at which the chemical is being introduced, then the process variable will overshoot its target (as described in Section 6.1.1 for a rising process). -
Page 41: Relay Off Delay
1. Select On. 2. Enter the value for the amount of time, in seconds, the relay is on (activated). Press Enter accept this value. 3. Enter the value for the amount of time, in seconds, the relay is off (deactivated). Press Enter accept this value. -
Page 42: Override
the actual pH of the process would drop to a dangerously low level and cause serious damage to the processing equipment. The overfeed timer option prevents this. By specifying the maximum amount of time that a relay can remain activated, the damage caused by a faulty probe signal is contained. Although this feature is turned off by default, we strongly recommend always setting this option. -
Page 43: Configuring Channel 1 Output
For either output the 4 mA and 20 mA values can be set to any value. Customizing the range maximizes the accuracy of the 4-20 mA signal. 6.2.1 Configuring Channel 1 Output 1. Enter the value of the process variable that corresponds to 4 mA. a. - Page 44 current output is proportional to the difference between the set-point of the process value and the actual process value, aka the error. Take the case of the process whose pH naturally rises and is controlled by dispensing acid (see Figure 6-2 below).
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Page 45: Ma Output - Channel 2 (Am-2250 And Am-2251)
Figure 6-3 Example of proportional control Note: The proportional control can only use one dispensing device (either acid or base). If process can naturally vary both directions consider using second 4-20 mA output or a pair of relays. 4-20 mA Output – Channel 2 (AM-2250 and AM-2251) The same instructions listed above apply to Channel 2. -
Page 46: Manual Test
1. Turn PID control On. 2. Set the value for K . Press Enter to accept it. 3. Set the value for K . Press Enter to accept it. 4. Set the value for K . Press Enter to accept it. 5. -
Page 47: Operation
7 Operation Run Mode Press from just about any menu to set controller in operation mode. The screen for “Run” mode shown on Figure 7-1 below. Note that AM-2250TX does not have a backlit display. Since there are no relays available, the relay status indicators are not displayed. Figure 7-1 AM-2250 or AM-2251 on the left and AM-2250TX on the right in "run"... -
Page 48: Diagnostics
As soon as main menu appears on the screen the controller automatically activates “Hold” mode. While you are in menu screen: • Process and temperature measurements are paused. • Activated relays are deactivated. • 4-20 output(s) freeze on the last reported value. Placing relays on hold during calibration is essential as calibration standards might activate their target (usually a pump). -
Page 49: Factory Reset
the electrode, changing the reference solution or changing the salt bridge. If the probe output does not change upon changing from one calibration solution to another then the probe is dead. The resistance of the temperature element should be close to the nominal resistance, which is usually either 300 or 1000 Ω. -
Page 50: Preferences
9 Preferences The Preferences menu has three options that only affect the user experience. Auto Return This feature allows you to return the 2250 to Run mode if you walk away from the 2250 while exercising a menu item. The choices are: If you choose “None”...