Allen Bradley PIDE-Manual/operator/program???

I've read 1756-rm006 and I can't fully understand what the difference is between manual and operator control mode. I'm used to "auto" and "manual" where the PID manipulates the CV while in auto and the operator directly manipulates the CV while in manual.

What are the differences between these modes and how do I track the setpoint to the CV while in anything other than auto so that the transfer is bumpless?

welcome to the forum ...

I can't fully understand what the difference is between manual and operator control mode

Click to expand...

first things first ...

are you sure that you didn't mean to say "between PROGRAM and OPERATOR control STATES?"

for this PIDE animal there are MODES - and there are STATES ...

the 4 available MODES are:
1. auto
2. manual
3. override
4. hand

the 2 available STATES are:
1. program
2. operator

so ...

your original question seems to be mixing apples and oranges (or at least - modes and states) ... we really need to nail down the details before we can start giving you concrete answers ...

Ron Beaufort said:

welcome to the forum ...



first things first ...

are you sure that you didn't mean to say "between PROGRAM and OPERATOR control STATES?"

for this PIDE animal there are MODES - and there are STATES ...

the 4 available MODES are:
1. auto
2. manual
3. override
4. hand

the 2 available STATES are:
1. program
2. operator

so ...

your original question seems to be mixing apples and oranges (or at least - modes and states) ... we really need to nail down the details before we can start giving you concrete answers ...

Click to expand...

What's confusing me is that I have the following PIDE inputs:
ProgProgReq
ProgOperReq
ProgAutoReq
ProgManReq
ProgHandReq

ProgProgreq as I read it is puts the PIDE into an ordinary "auto" mode, though I don't understand the difference between ProgProgReq and ProgAutoReq. Nor do I understand the difference between "hand" and "manual". In my experience, those two terms have always been used interchangeably.

Does "progoperreq" simply put the PIDE into a state where it can be in manual/hand?

http://literature.rockwellautomation.com/idc/groups/literature/documents/wp/logix-wp008_-en-p.pdf This white paper should give you a good understanding on how to set up the PIDE function.

dragonx556 said:

http://literature.rockwellautomation.com/idc/groups/literature/documents/wp/logix-wp008_-en-p.pdf This white paper should give you a good understanding on how to set up the PIDE function.

Click to expand...

Thank you for that. So, from that white sheet I read:

Mode Control Options
The PIDE instruction provides additional capabilities through the use of many different modes of control. In addition to the traditional modes such as auto and manual, the PIDE instruction also supports the concept of Program/Operator control to define who is allowed to make changes to the
loop.

If the loop is in Program control, the user program can place the loop into the appropriate mode (e.g., Auto/Manual), and change the setpoint or manual output of the loop.

Conversely, if the loop is in Operator control, the operator can change modes and values.


The supported control types and loop
modes are:

Mode Usage
Program Control When in Program control, the loop mode is determined by the user program. The user program can also change the setpoint and manual output of the loop.
Operator Control When in Operator control, the loop mode is determined by the operator. The
operator can also change the setpoint and manual output of the loop.


So in Program control, the user program can change the setpoint and manual output of the loop. But in Operator control, the operator can also change the setpoint and manual output of the loop.

Correct me if I'm wrong (PLEASE!). Does this mean that program control is essentially "AUTO" and operator control is essentially "manual"?

your request:

Correct me if I'm wrong (PLEASE!). Does this mean that program control is essentially "AUTO" and operator control is essentially "manual"?

Click to expand...

no – it's not that straightforward ...

there are TWO "STATES" ...

here are the BASIC ideas:

(1) while in the PROGRAM state – the PLC's code/logic controls the operation of the PIDE ...

then - under the PROGRAM state, the PIDE can be in any one of the following four MODES:

1. auto mode
2. manual mode
3. hand mode
4. override mode

(2) while in the OPERATOR state – the operator (usually named "Bubba") is in control of the PIDE ...

then - under the OPERATOR state, the PIDE can be in any one of the following four MODES:

1. auto mode
2. manual mode
3. hand mode
4. override mode

TIP: the biggest BASIC difference in the manual – hand – and override modes is WHERE (which variable location) you put the number that you want to use ...

so ...

your FIRST step in tackling this thing is to decide whether you want to operate it in the PROGRAM state – or in the OPERATOR state ...

then (and only then) you're ready to decide which MODE you want ...

just be careful with the white paper that's been mentioned ... the BASIC ideas should be helpful with the MODE concepts – but below is shown one of the typographical errors in it ...
.

If you only plan to use the PIDE function so that an operator gives the PIDE a set point while in auto mode, or has the ability to switch the PIDE in auto/manual, then it does not matter if you keep the PIDE in program mode or operator mode. Whichever mode you choose, you need to make sure you are manipulating the correct parameters.

If you want to use program mode, set ProgProgReq = 1 and ProgAutoReq = 0, and then you set ProgAutoReq to 1 and ProgManualReq to 0 when you want the PIDE to operate in automatic control. Set ProgManualReq to 1 and ProgAutoReq to 0 when you want the operator to be able to set the PIDE CV by putting a value into CVProg.

If you want to use operator mode, set ProgProgReq = 0 and OperOperReq = 1, and then you set OperAutoReq to 1 and OperManualReq to 0 when you want the PIDE to operate in automatic control. Set OperManualReq to 1 and OperAutoReq to 0 when you want the operator to be able to set the PIDE CV by putting a value into CVOper.

I have only ever used one mode or the other. The example the white paper gives for when you would use two modes is if you have a special start up sequence that you do not want the operator to interfere with. You would accomplish this by having your HMI target the OperAutoReq, OperManualReq, and CVOper, which will not affect the operation of the PIDE while it is in program mode running whatever start up sequence you programmed.

dragonx556 has pretty well summed it up for you ... run a few experiments and see how close you can come ...

good luck with it ... offline for a day or so ...

Right now, I'm trying to reverse engineer an existing program. And I'm new to Allen Bradley, so I'm trying to understand why the program was written as it was. I'm trying to understand the "why" behind the "what".

The program was written in function block, which is why the standard PID wasn't used. Though, because the derivative isn't needed, I can imagine a PI block could be substituted instead.

Ron Beaufort said:

dragonx556 has pretty well summed it up for you ... run a few experiments and see how close you can come ...

good luck with it ... offline for a day or so ...

Click to expand...

Thank you both for the help

Though, because the derivative isn't needed, I can imagine a PI block could be substituted instead.

Click to expand...

I wouldn't try that if I were you ... for one thing, the PI instruction doesn't use the same units for tuning ...

http://www.plctalk.net/qanda/showthread.php?p=504605&postcount=3

.

ProgManReq, but in PID instead of PIDE?

Sorry to jump in,

I want to ask is it possible for a regular PID in ladder logic to achieve mode like ProgManReq which is available in Enhanced PIDE FBD? PID only have .SWM and .MO bits to set the modes/states, so not sure how to set it up.

Thanks in advance!