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APPENDICES
A | PID Tuning Procedure
The PF2100’s default PID settings should result in good temperature control in most common heater
applications. If the temperature control is unstable or if faster control response is needed, the following
procedure can be followed to adjust the PID settings. This procedure is not a comprehensive method for
adjusting PID Controllers but provides some general guidelines. This procedure is iterative and therefore
may require a significant amount of time to follow.
TUNE THE PROPORTIONAL BAND SETTING
1. Start with the Proportional Band Setting set to a large value
such as 500% and with the Integral and Derivative settings
set to their default values (4.0min/rst and 0.0min respectively).
2. Make a small step change (such as 5%) to the Process
Setpoint and monitor the resulting temperature change.
3. Repeat decreasing the Proportional Band Setting in 50% steps
until a Process Setpoint change results in overshoot of the
Process Setpoint or until oscillation results.
4. Increase the Proportional Band Setting until overshoot and
oscillation no longer occur.
TUNE THE INTEGRAL SETTING
1. Set the Integral setting to 10min/rst.
2. Make a small change to the Process Setpoint and monitor the
temperature change.
3. Repeat decreasing the Integral in ½ minute steps until a
Process Setpoint change results in overshoot of the Process
Setpoint or until oscillation results
4. Increase the Integral Setting until stable.
TUNE THE DERIVATIVE SETTING
If there is noise on the thermocouple inputs, using the Derivative Setting can dampen the effects of the
Proportional and Integral Settings. For this reason, the Derivative Setting can usually be left set at zero
unless a very fast response is needed. If it is required, follow this tuning procedure:
1. Set the Derivative Setting to 10 minutes.
2. Decrease the Derivative Setting until a small Process Setpoint
change results in a fast response with some oscillation
3. Increase the Derivative Setting until the oscillation in response
to a Process Setpoint change is dampened
B | Field Calibration
It is possible to field calibrate the thermocouples, the 4-20mA Output, and the two 4-20mA Inputs on
the 4-20mA Expansion Card. In general, it should not be necessary to do this in the field because the
system has already been calibrated at the factory. However, there are circumstances where this may be
necessary such as if the door or terminal card was replaced in the field or if the system is very old and
has drifted out of calibration. Before recalibrating the system, it is strongly recommended that you explore
all other possible solutions first. Be sure to verify that system settings are correct and that the devices
attached to the system are calibrated correctly. If it is deemed necessary to proceed with recalibrating
the PF2100, follow the procedures below carefully. Failure to perform the calibration correctly may result
in worse performance than if the system had been left alone.
The PF2100 uses a two-point calibration system to provide readings with greater accuracy than a single-
point offset calibration. The first point compensates for any fixed offset in the system and the second
point defines the slope. If the calibration fails for any reason, there is an option in the calibration menu to
clear all calibration data.
CALIBRATING THE THERMOCOUPLES
For thermocouples, the first calibration point is zero volts which corresponds to the ambient temperature
of the terminal block where the thermocouple plugs into the Terminal Card. The second calibration point
is referenced to a known temperature that is well above the ambient temperature. This temperature is
typically the hottest temperature at which the system will operate but should not be higher than 750˚C
above ambient and should not be lower than ambient + 20˚C.
1. Make sure that the system is stopped.
2. Remove the 3 pairs of thermocouple wires (High Temp,
Process, and Aux) from the P8 Pluggable Header on the
Terminal Card.
3. Press the UP and Down Keys simultaneously to unlock the
Calibration Menu (menu 7) and to show the temperature
debug screen in the ready menu, which are normally hidden.
4. Short each pair of thermocouple inputs individually using a
jumper or short piece of copper wire (ie, short HT+ to HT-,
short Proc+ to Proc-, and short Aux+ to Aux-) and make
note of the TH, TP, and TA temperature values show on the
debug screen (press down or up on the ready screen until all
temperatures are shown at once).
5. Reconnect the 3 pairs of thermocouple wires (High Temp,
Process, and Aux) using the full length of wire used at the
installation to the P8 Pluggable Header on the Terminal Card.
6. Set the High Temp, Process, and Aux thermocouples to a
calibrated reference temperature equal to the temperature
values read in step 4 using a dry block or other calibrated
reference.
7. Press the Menu Key repeatedly until menu 7 is shown.
8. Press OK. If prompted, enter the L2 Password:
9. “Cal Proc TC Zero” will show on the display.
10. Press OK and the message “Calibrating Wait…” will appear
on the display for about 5 seconds. Afterwards, the message
“Parameter Saved” will show on the display briefly.
11. Press the Menu Key to go to the next item.
12. Repeat steps 10 and 11 for the “Cal HiTemp TC Zero” and “Cal
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