If you also have examples of this logic that would be even better. 

See also the attached sketch.

Word logic operations -> SEL - but this won't be bumpless.

Search here for RAMP generator topic to achieve no jumps in output. It was somwhere here...

Thank you Jacek.

But I am a terrible *** - can you expand a bit more perhaps show an code bit where you used these functions (one or even better both parts) ?

Hi

Well i have gone through your query, First the lets call the Parameter Set 1 as - Set1 and next one as Set2

You want a bumpless change over to Manual value that is the operator value. Then the operator value has to track(Transfer the Output value to Operator value)  the output value during the external Set2 PID output. Then when you change with Bool value the output and Input (Set1) in our case shall be the same and shall be bumpless.

Unless you track the Operator or the manual value with the Output value it aint going to be bumpless.

You can write a small code for that, In case you have problem tell us.

Thanks Tagolover,

I am a terrible newbie so I will admit that I don't know how to program what you describe. I am surprised that such a function/instruction does not already exist in the SW - like a counter or a timer.

I have taken the first 2 courses in TIA S7 - and they are almost exclusively about ladder programming so that is what I am using.

I would be thankful if you could show me an example of how to program this.

I have made a crude switch (not bumpless) for something else and I might use it here also if I can't find a smarter way (see attached).

xmnj

can you expand a bit more

The SEL operator should be no problem to you as it works exactly the way your pdf shows.

How to write RAMP function block you can learn here.

Thanks again Jacek.

You are quite right - the SEL operator is what I was looking for. I will read up about the ramp function.

jacek d

The SEL operator should be no problem to you as it works exactly the way your pdf shows.

How to write RAMP function block you can learn here.

I'm confused about the need to program ramp. Isn't ramp up/down speed something you usually program in the drive?

Adam

Hello Adam.

In some chemical processes for example you need to ramp the setpoint up to the desired level in a controlled way. Other processes need to vary the rate of change according to the condition.

The actuator might be a drive-motor combination but it is not always the case. Even then the case may be applied.

Cheers.

adam_ski

I'm confused about the need to program ramp. Isn't ramp up/down speed something you usually program in the drive?

Adam

Thanks #dP. I understand your point. The sentence "Ideally the switch over should be “bumpless” and also follow a ramp" didn't emanate need for strict control over ramp. We sometimes invent problems when solutions are easily available :-)

Regards,

A.