Frequently Asked Questions - Temperature Controllers
1. What does PID mean?
PID is an acronym for Proportional, Integral, and Derivative. It is a three mode control action where the temperature controller has time proportioning, integral (reset), and derivative (rate) action.
View our PID controllers.
2. What does a temperature controller's autotune do?
Autotune automatically selects the PID parameters of your system based on its dynamic characteristics and stores them in the controller's EEPROM for future use. Autotune need only be run once for a system. However, if the load changes significantly, the set point is changed, or some other fundamental system characteristic is changed, it may be necessary to re-tune the system. Caution must be exercised when initiating autotune: by its nature, autotune creates system overshoots. If a process cannot tolerate excessive overshoot or if a system is very dynamic (process variable changes very quickly), the resulting overshoot may cause material or system damage.
3. Why can't I change my Fuji controller's parameters/setpoint?
There are three possible answers:
- Check the lock level parameter to be sure that it isn't set to "locked" (refer to your manual for lock levels in your Fuji controller.)
- Check to make sure that your ramp/soak programming isn't enabled.
- If you have a Fuji controller with the remote setpoint option, the setpoint isn't able to be changed when the remote setpoint is activated. You will need to either deactivate the remote setpoint in order to change the setpoint or change it from the remote location.
4. My controller isn't controlling my process very well - it seems to be over, and under, shooting my set point. What is wrong?
Make sure that you have used the autotune procedure on your new controller. Every process is different, and the controllers come from the factory with preset generic values. Make sure that it is tuned to your specific process. Many times, using the autotune feature will solve the problem. In addition, you may need to manually tune your controller if it is being used in a very dynamic or static process. Consult your manual for complete instructions on how to tune your controller, or call us at 800-884-4967 for immediate assistance.
5. How many different controllers does Instrumart offer?
6. I have a Fuji PXR controller and need to unmask several parameters temporarily for programming purposes. What's the easiest way to do this?
Parameter masking is controlled by the values stored in parameters DSP1 through DSP13. To quickly unmask all parameters, just set DSP13 to 255. If you have a Fuji PXR temperature controller, parameter masking is controlled by the values stored in parameters DSP1 through DSP7.
7. Can a Fuji PXR controller be switched from a thermocouple to an RTD or vice versa in the field?
Yes, simply change the PN-2 program parameter.
8. Can a PX Series controller be switched from a TC/RTD model to a VDC/mA model in the field?
No, the unit must be sent to Instrumart for re-calibration. For a true universal input controller, please consider the Fuji Electric PXG Temperature Controller.
9. Is it possible to limit the output (manipulated variable or MV) of the Fuji Electric PX Series controllers?
Yes; the Fuji Electric PXZ and PXW temperature controllers have undocumented parameters which allow a user to define both a maximum and minimum percentage output when using proportional control. This is true of both time proportioning control (relay, dc pulse, or triac outputs) and proportioning control (4-20 mA). For example, if a simple pressure control system utilizing a 4-20 mA valve control signal cannot tolerate a fully open valve, the high output limiter could be set to 50% (12 mA), 75% (16 mA) or any value between -3.0 and 103.0% to prevent the valve from fully opening. The parameters used to limit the output are PLC1 & PHC1 for the primary control output and PLC2 & PHC2 for the secondary output. The "PLC" parameter is the low output limiter and is factory preset at -3.0%. The "PHC" parameter is the high output limiter and is factory preset at 103%. A related and equally important parameter when setting output limits is the PCUT parameter. Setting this parameter dictates how the output limits will function outside the proportional band. Call Instrumart for additional information regarding the PCUT parameter if your application requires output limits. All parameters associated with limiting the control output must be unmasked before programming. For display code and parameter menu location, consult your PXZ or PXW manual.
10. Is the new Fuji PXR temperature controller a direct replacement for the PXZ and PXW series?
11. How do I program the PX/PXR/PXG series controller for on/off control?
Set the proportional band parameter (P) to 0 and set the hysteresis to the desired value. It does not matter what the Integral (I) and derivative (d) terms are set to. Make sure that TC is set to a value larger than 0.
12. Is a triac output available for PXR series controllers?
Yes, except for the PXR3 1/32 DIN size units and only for switching AC control level voltages. Specifications for the triac output are 0.3A, 240V AC with maximum AC current leakage of 1.5 mA.
13. Can you change a PX/PXR Series controller from ºF to ºC, or vice versa?
Yes, simply change the program parameter P-F.
14. Why can't I find the parameter P-F on the PXR Series?
It probably is just hidden. You need to uncover this parameter in the new PXR Series, if it is not visible. To make P-F visible in the PXR Series subtract 4 from the number in DSP5 in the second menu block. Please see the manual for instructions, or call us at 800-884-4967 for immediate assistance.
See Our Temperature Controllers
- Fuji Electric PX Series - Dual Display Self-Tuning Process and Temperature Controllers have 8 Ramp / Soak Segments
- Fuji Electric PXR Series - Self-Tuning Process/Temperature Controllers with 16 Ramp/Soak Segments
- Fuji Electric PYX Series - Fuzzy Logic Controllers with Universal Input
- Sixth Sense AI-100 - 1/32 DIN Fuzzy Logic Temperature Controller with RS485 Communications Option
- Fuji Electric PXG (PID Series) - 1/16, 1/8, and 1/4 DIN PID Process and Temperature Controllers
- See all temperature controllers.