Process Control Frequently Asked Questions
Use "Ctrl-F" to search for specific words in this FAQ.
Question:
What is a limit controller?
Answer
Limit controllers are a specific type of process or temperature controller whose alarm outputs latch when energized and must be manually reset. We don't sell any limit controllers, although we do carry on/off controllers whose main difference is the outputs do not latch.
FAQ ID: 913
Question:
Why must a controller be tuned and if so when?
Answer
Process controllers must be tuned because no two processes are alike. What works for one will not necessarily work for another.
Tuning can be performed anytime an installation occurs, new component installed, or anytime the installers feels that better performance can be obtained. It's solely up to the end user and the process that is being controlled.
FAQ ID: 914
Question:
Do you sell a 24VDC version of the PM24, TC33, PC35, or Solo controllers?
Answer
The PM24, TC33, and PC35 models have been discontinued.
However, the SOLO Standard Temperature Controllers have 24VDC versions available.
FAQ ID: 915
Question:
What is the input sampling rate?
Answer
Solo controllers
- Thermocouple input: 400ms per scan
- Platinum RTD: 400ms per scan
- Analog: 150ms per scan
FAQ ID: 916
Question:
Can the units communicate to external devices?
Answer
To configure your Solo controller from a PC, you can use the SL-SOFT software and the USB-485M convertor.
The Solo controllers can communicate via RS-485 Modbus RTU or Modbus ASCII protocol as Modbus slaves. That means that any of our PLCs that have RS-485 capabilities (Click, Do-More, and Productivity) can communicate with the controllers.
The ProSense Advanced Process Controllers also have RS-485 capabilities. You will need the PPC5 Controller Software, as well as the USB-485M convertor, for configuring the controller.
FAQ ID: 917
Question:
How can I set the controller to on/off control?
Answer
The Solo controllers have a parameter, CTRL, which you use to select the control mode, either PID, ON/OFF, MANUAL, or PROGRAM (for ramp/soak).
FAQ ID: 918
Question:
How do I change from F to C degrees?
Answer
Solo: If the input type is a thermocouple or RTD, the TPUN parameter lets you select either F or C.
Prosense Advanced: The UNIT parameter lets you select either F or C.
FAQ ID: 919
Question:
Why does the temperature go down instead of up when the heat is applied?
Answer
You have the sensor leads reversed.
FAQ ID: 920
Question:
What is a PID/Process controller?
Answer
This type of feedback controller has a single-loop (one channel of control) and utilizes a PID (proportional-Integral-Derivative) control algorithm.
The output (control variable or CV) of this controller is based on the error created by a user defined set point (SP) and a process measurement (process variable or PV).
The PID algorithm defines how each element acts on the error signal created.
Proportional
- The proportional term simply responds proportionally to the current size of the error.
- The loop controller calculates a proportional term value for the PID calculation.
- When the error is zero, the proportional term is also zero.
Integral
- The integral (or reset) term integrates (sums) the error values.
- Starting from the first PID calculation after entering auto-mode, the integrator keeps a running total of error values.
- The running total represents the constant output required to hold the current PV.
Derivative
- The derivative (rate) term responds to change in the current error value from the error used in the previous PID calculation.
- Its job is to anticipate the probable growth of the error and generate a contribution to the output in advance.
FAQ ID: 921
Question:
When I press and hold the "setup" key on the PC35 to configure the controller, the display flashes between settings. Why does it flash?
Answer
The "setup" key must be used in conjunction with the "back" key. This allows the user to step through all of the cycles. The flashing is an indication that an illegal operation has been performed.
The PC35 has been discontinued
FAQ ID: 923
Question:
How many feet of thermocouple wire can I use?
Answer
There is an input limitation of >4.7M for the Solo controllers. Review the specifications of the thermocouple wire (diameter, distance, material, etc.) to make a determination of distance limitations.
If the environment is electrically noisy or the run exceeds the limitations of the controller, then a Signal Conditioners can be used to convert it to a 4-20 ma input.
FAQ ID: 926
Question:
What is retransmission on the PC35 controllers?
Answer
It is the exact 1-1 ratio of the input retransmitted to other controllers or chart recorders.
The PC35 has been discontinued
FAQ ID: 927
Question:
How should I wire your RTD0100 series of RTDs to the FC-R1 RTD signal conditioner?
Answer
The RTD0100 series is our four wire RTDs. Two each of the wires are connected to each side of the RTD.
PIN # WIRE COLOR
- 1 BROWN
- 2 WHITE
- 3 BLUE
- 4 BLACK
So for our RTDs
- BROWN and WHITE are connected to the same point on the RTD
- BLUE and BLACK are connected to the other point.
The RTD input of the FC-R1 has three connections:
- + (plus)
- - (minus)
- COM.
In order to wire our four wire RTD to the FC-R1 input,
- one of the wires should remain disconnected on the RTD0100 cable.
- The other wire that connects to the unused wire on the RTD is the wire that should be connected to the + (plus) terminal of the FC-R1.
As an example,
- If you don't use the BROWN wire in the RTD0100,the WHITE wire should be connected to the + (plus) terminal.
- The other two wires, BLUE and BLACK in this example, should be connected to the -(minus) and COM terminal.
- It does not matter which color is connected to which terminal for these two wires.
To restate the example,
- don't connect the BROWN wire of the RTD0100 to anything.
- Connect the WHITE wire to the + (plus) terminal of the FC-R1
- connect the BLUE wire to the -(minus) terminal
- and the BLACK to the COM.
This will properly connect the RTD0100 to the FC-R1. Other combinations can be wired and be correct, but this is an illustration of one combination.
If you need to extend the wire for the RTD run, we recommend Q7525-1 or equivalent.
FAQ ID: 1266
Question:
Can the SOLO Ramp/Soak function be turned on remotely from an external input?
Answer
Yes
- If you use the SOLO 4896 or 9696 models you can use Event Input 1 to enable or disable your Ramp/Soak operation.
- If Event Input 1 is closed ( a contact is closed between terminal #3 SG and terminal #4 Ev1) the output will be disabled and the Ramp/Soak operation will cease its operation.
- Upon opening the contact between SG and Ev1 the Ramp/Soak will start its operation again at Step 0.
- It will not resume operation of the Ramp/Soak table from the point the contacts were closed.
FAQ ID: 1267
Question:
Can you pause a ramp/soak pattern in the Solo controller? What happens if the unit loses power while running a ramp/soak pattern?
Answer
You can pause a ramp/soak pattern during operation. In the run/stop parameter, (r-S P2-1), when you're doing ramp/soak control, you have the option to RUN the profile, PSTP the pattern, which resets the pattern to step 0 and stop operation, or PHOD the pattern, which holds the pattern and restarts at the exact point you held it when you go back to RUN.
If the Solo is running a ramp/soak profile and the power is removed and re-applied or it goes from RUN to PSTP, the current ramp/soak pattern will restart at step 0. Note that if the current running pattern consists of multiple patterns connected together, it will start at the beginning pattern number for that profile.
FAQ ID: 1276
Question:
What are the color codes for American and Canadian Thermocouples?
Answer
All American/Canadian Thermocouples follow the ANSI color standard for wire coloration. Jacket color may sometimes be the main wire color, but it is not a dependable means of thermocouple type.
Type J - White/Red
Type E - Purple/Red
Type K - Yellow/Red
Type T - Brown/Red
Type N - Orange/Red
Red is always Negative.
FAQ ID: 1304
Question:
How does the FC-11 respond to a break in the input loop or loss of connection at the input?
Answer
If the A connector is disconnected (input loop is broken) it will output approximately 3mA
FAQ ID: 1314
Question:
Why does my Solo software appear "chopped off" at the bottom of my computer monitor?
Answer
This applies to the original Solo software V1.x. The software is designed around a minimum resolution of 1024 x 768 and 96 DPI.
Please use the latest version of the Solo Configuration software SL-SOFT
FAQ ID: 1332
Question:
How does the Solo temperature controller calculate PID
Answer
Please see AN-LC-012 for more detailed explanation.
FAQ ID: 1502
Question:
How do I loop Ramp/Soak patterns in a Solo controller?
Answer
If you need a total of 11 Steps, for example, you need to enter all the Steps for Pattern 0 ( 8 steps), and then the first 3 Steps of Pattern 1.
PSY0 for Pattern 1 will be set to "7" ( 0-based, so all 8 Steps run).
Then set CYC0 to "0" ( no repeat of this pattern).
Then set Lcn0 to "1", (this is the pattern that will be started after the completion of Pattern 0).
Set PSY1 to "2", so the first 3 Steps of Pattern 1 will be run (remember, 0 based, so it's Steps 10-12).
Set CYC1 to "0", so there is no repeat of this pattern.
Set Lcn1 to "0", so that it goes back and runs Pattern 0 again.
The Solo will continuously run this 11 Step pattern while power is applied.
FAQ ID: 1532
Question:
In the Solo controller, if I have a 4-20mA input and output 1 is a 4-20mA output, the output works fine when tested by a meter. however, when I connect the output to my 4-20mA input device the Solo output goes to maximum current and won't change.
Answer
The Solo units have no electrical isolation between the 4-20mA input and the 4-20mA output. For devices that require electrical isolation, connection to those devices cause the output to go to maximum and not adjust. You will either have to isolate the current output of the Solo or use a different controller that provides the electrical isolation your device requires.
FAQ ID: 1583
Question:
Does SoloSoft software support higher than COM8?
Answer
The original Solo software V1.x. It was limited to what COM ports it could use.
Please use the latest version of the Solo Configuration software SL-SOFT
FAQ ID: 1586
Question:
What Exception Responses do the Solo temperature controllers support?
Answer
Response Codes [MB address + (function code + 80H) + Error code]
Error Code -- Error Definition
01H - function code is not supported
02H - Illegal function address
03H - Illegal read/write word count
Response Codes [MB address + (function code + 80H) + Error code]
Error Code -- Error Definition
01H - function code is not supported
02H - Illegal function address
03H - Illegal read/write word count
04H - Data process fail
09H - Checksum error
Exception 4 is often caused by Writes to the Solo, but not having parameter CoSH set to 1 or Yes can cause this error.
FAQ ID: 1599