OT: Omron temperature controller E5EN-HPSS2B-500

[theripley]

CAUTION: This will be a long post.

Please give me some light, I am so lost with the omron temperature controller that we are using to proportionally control a motorized valve.

We have a steam room, where parts are being tested. The room has to be maintained at 75, 85 or 95 deg. C depending on the parts. Since we are aiming for a proportional control, I was expecting the movement of the valve will be in proportion to the difference of the SV & PV. Hence, if SV-PV = 10%, valve movement is 10%.

My motorized valve responds to 4-20mA and judging from the wiring diagram of the temperature controller (see manual1 pic), I can only connect it to the transfer output. However upon checking the manual, this transfer output has generally 3 functions (see manual2 pic): Set point, PV & valve opening. Our motor valve does not have a potentiometer, hence we cannot use the valve opening function.

Upon testing, we found out the ff:
1.) Set point function --> the valve opening is proportional to the value of the set point. Hence, if set point is 85 deg. C, valve opening is 85%. The valve opening does not change as long as the set point remains the same.

2.) PV function --> the valve opens & closes in proportion to the actual temperature. Hence, if actual temperature is 50 deg. C, valve opening is 50%. If actual temp increases, the valve opening increases while it closes with the decrease of the latter.

This controller does not seem to make any sense. Has anyone use this controller? What am I missing out with this one?

Please help.

 

[danw]

I've never used an Omron, but I might be able shed some light here.

1) no 4-20mA control output?
I'm surprised that the controller does not have a 4-20mA control output, which is what you want. Although the output terminals 3/4 are labeld (-)/(+) I suspect that is polarity for low voltage binary switching.

Are you sure there is no 4-20mA control output? (you only provided 2 pages from a multipage manual)

2) Transfer Function

It appears that the 4-20mA output is configured with a transfer function. Here's my speculation on the interpretation of transfer function

SP or SP during ramp: What ever the setpoint is, is retransmitted as a 4-20mA signal for applications like multizone ovens, where a change on the master controller's setpoint is retransmitted to slave zone controllers for use as their setpoint. It is not a control signal, it is a re-transmit signal

PV: If the input is an RTD, there's not way to use the RTD output in another device. So the temperature value (PV) is retransmitted to whatever (recorder/indicator/alarm). It is not a control signal, it is a re-transmit signal.

MV Monitor (Heating): manipulated variable, the controller output, reverse action for heating
MV Monitor (Cooling): controller output, direct action for cooling

Valve opening: ? What's the note say?

I think the MV Monitor Heating will provide the control output via 4-20mA that you're looking for. MV, the manipulated Variable is the controller output. Presumably a PID controller's MV is the output of the PID calculation.

You can test by making the selection and seeing what the 4-20mA does in response to a SP or PV change.

3) Tuning
> if SV-PV =10%, valve movement is 10%.
That applies only for a gain of 1 or a proportional band of 100, no rate, no reset.
The tuning constant determine how much the output changes for a given error value.

4) FYI
Position proportional has historically meant 2 binary outputs, one drives closed, the other drives open AND slidewire feedback for true position control (slidewire indicates motor shaft position).

 

[gclshortt]

https://www.ia.omron.com/products/family/1947/lineup.html

It looks like you are looking for a E5EN-HAA2HBM-500. See the above specification sheet.
You can then add the control outputs to the unit as required - E53-C3N - This is a current output 4 to 20-mA DC, load: 600 Ω max., resolution: approx. 10,000

This would be your control output and not the transfer output.

Hope this helps you out.
Regards,

 

[theripley]

2) Transfer Function

It appears that the 4-20mA output is configured with a transfer function. Here's my speculation on the interpretation of transfer function

SP or SP during ramp: What ever the setpoint is, is retransmitted as a 4-20mA signal for applications like multizone ovens, where a change on the master controller's setpoint is retransmitted to slave zone controllers for use as their setpoint. It is not a control signal, it is a re-transmit signal

PV: If the input is an RTD, there's not way to use the RTD output in another device. So the temperature value (PV) is retransmitted to whatever (recorder/indicator/alarm). It is not a control signal, it is a re-transmit signal.

>>> If it intends to re-transmit signal only, why did they ever call it a temperature controller? This thing only mimics PV or SP The heck!

Valve opening: ? What's the note say?

>>> According to the manual, this parameter monitors the valve opening during operation.
• This parameter monitors the valve opening when position-proportional
control is used.
• The valve opening can be monitored if a potentiometer is connected and
motor calibration is executed.

>>> in case my motor valve have a potentiometer, will it affect how the valve opens/ closes? Or is potentiometer's purpose is only for monitoring?

>>> By the way, what do they mean with position-proportional?

 

[osmanjdt]

i'm confuse with you statement,

if SV-PV = 10% THEN the movement 10%,

the process must SV=PV (reverse action) fully open

 

[danw]

1) >>> If it intends to re-transmit signal only, why did they ever call it a temperature controller?

The model you have will do heat/cool temperature control but its outputs are switching outputs for solenoid valves, on-off actuated valves, electrical contactors, solid state relays and position proportional actuators. That capability qualifies as "temperature controller" any day. In fact it is a fairly high end temp controller.

It happens that you have a model that does not have a 4-20mA control output, but there is another model that does have a 4-20mA output, as pointed out by Garry.

The re-transmit output is a high-end option and is configurable to do what most re-transmits do. So you luck out using that model.

2) Valve opening: ? What's the note say?

Thanks for providing the manual definition. I would have called it "valve position" - it is probably a retransmit of the slidewire input. There are applications that position re-transmit.

3) >>> in case my motor valve have a potentiometer, will it affect how the valve opens/ closes? Or is potentiometer's purpose is only for monitoring?

The slidewire/potentiometer tracks the position of the motor shaft.

If the actuator has a 4-20mA input, all you need to do is connect the 4-20mA control output (in your case the transfer function MV heat) to that input. It is assumed that a 4-20mA input on an actuator uses the slidewire feedback internally to position the motor where it needs to be according to the 4-20mA demand/setpoint signal.

So an unconnected slidewire has no effect on how the valve opens or closes, it is feedback monitoring.

4) >>> By the way, what do they mean with position-proportional?
Position proportional means the controller has 2 switching binary outputs. One output drives the actuator closed, the other output drives the actutor open. Typically, the outputs use common return, so it takes 3 wires, OPEN, CLOSE, return. The slidewire indicates the motor shaft position and the controller uses that as feedback which it uses to 'bump'/move the actuator until the shaft position equals the demand/setpoint. (slidewire indicates motor shaft position).