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Before you call, please look at this section to see if your question is covered here. If you do call for technical
assistance, be ready to supply the following information:
• complete model number of controller
• symptoms of the problem
• unusual events, if any, that preceded the problem
• remedies you have already tried
Q.
A. To change the type of sensor used (or to switch to a linear input), go to the input menu and change the
input.
Unless the controller was ordered with the “calibrate all” choice, you must also re-calibrate the controller for
the new sensor type. (To determine whether the controller in hand was calibrated at the factory for all input
types, check the model number on the label on the controller. The meaning of each character in the model
number is in the installation manual supplied with the controller.)
Because all temperature inputs (RTD and thermocouple) require the same input jumper settings, you do not
have to change JMP01 or JMP02 on the processor board. However, if you change from a temperature input
to a voltage signal above 100 mV or to a current input, you must change the jumper settings.
Q. Why doesn’t the PV displayed match the value on a thermometer in the process?
A. Unless the thermometer and the sensor providing input to the controller are very close to one another,
their readings will not match in some applications, because of temperature variations within the process.
However, if you want the controller to maintain the setpoint value at the location of the thermometer, instead
of at the location of the sensor, use the input menu’s bias parameter for RTD or thermocouple inputs.
For example, suppose you want the process to be 150
o
F. However, the sensor providing input to the
controller is so close to the heater that it reads 50 degrees higher than the process at the location of interest
to you. Enter -50 as the bias value. Enter the setpoint of 150. The setpoint 150 will be displayed. However,
temperature at the sensor location next to the heater is 206
o
F, the controller shows 156, the temperature at
the location of interest in the process.
Q.
A. If the controller’s output type parameter is set to PID, the controller attempts to moderate the rate of
will apply 100% output if the process temperature is below the setpoint and 0% if the PV is at the SV.
apply 100% output if the process temperature is above the setpoint and 0% if the PV is at the SV.
is greater oscillation of the process temperature. (If there is still too much cycling, introduce hysteresis to the
Q. Why doesn’t the controller communicate with the host computer?
A. When a controller has been communicating successfully with a MODBUS master or Multi-Comm host
computer, then stops communicating, the cause is most likely damage to the network wiring. However, be-
fore going to search for the fault, take a quick look at the communication settings on the serial menu. Make
sure that the controller ID has not been changed, and that the other communication settings match those
used by the host.
Q.
A.
sometimes so quickly that the value is hard to read. Go to menu 05 and increase the value of the FILt
time period over which the controller will average the input values before using the value in the calculation of
control output values.
FAQs
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