Using the analog input of powerflex 525 VFD

[zmmarsad]

Hi,

I have a potentiometer connected to a siemens micromaster 440 to control a servo motor speed and they are not connected to any PLC. Now, I am trying to get the potentiometer to another panel where I have a powerflex 525, PLC, and a HMI. Can I connect the analog input of the siemens drive to the powerflex 525 analog input and control the speed from HMI? Given the situation that I do not have any analog input left to the PLC.

As I am a beginner, there might be some vague questions. If you need further information, please let me know.

Thank you

 

[danw]

An Analog output connects to an analog input, an analog input does not connect to analog input.


HMI's generally do not have I/O, the PLC has I/O. Does the PLC have an analog output?



It is common to control the speed of a drive from manual input on an HMI that communicates to the PLC whose analog output signal is connected to a drive.


It is not a wave-a-magic-wand implementation.

 

[parky]

What may be possible is if the Siemens drive has an analogue output you could set this to give an analogue referencing the speed then connect this to the 525, however, you would ideally need to check that these analogue outputs/inputs are isolated or they might smoke.

 

[zmmarsad]

Thank you for your response!

The PLC does not have any analog output. That's why I am trying to use the powerflex 525 analog ports. How do I connect this two drives?

 

[RonJohn]

Welcome to the forum, zmmarsad!

Thank you for your response!

The PLC does not have any analog output. That's why I am trying to use the powerflex 525 analog ports. How do I connect this two drives?

Sparky didn't mention anything about a PLC analog output but rather a Siemens drive analog output.

It is unclear whether you want to:
A. Use one potentiometer to control both the Siemens drive AND the PowerFlex 525
B. Use the HMI to control the PowerFlex speed
C. Something else

Please clarify what you want to control each drive speed.

 

[parky]

From a quick scan of the manual the Siemens has a 0-20ma output & the 525 has a 4-20ma input so it looks like if you want to slave the 525 from the 430 then you would need a 0-20 to 4-20ma isolated converter, the Siemens would give out a value based on the speed & this would then drive the 525 if that's the way you want to go, connecting a pot to both probably would not work as both have their own 0-10v supply alternatively replace the pot with a dual gang one & trim the drives so they follow.

 

[zmmarsad]

Ron,

I only want to control the siemens drive from the HMI. The powerflex 525 is the way to connect it to the HMI.

 

[Helliana]

If my understanding is correct, you are trying trying to use the AB drive as remote IO to control the Siemens drive. I know this can be done with Powerflex 750 series drives. You have to set the Parameter 75 [Anlg Out0 Sel] to be Parameter 76 [Analog Out0 Stpt]. You can then create a datalink in the processor for Parameter 76 and adjust accordingly.


You may be able to do the same thing on the Powerflex 525, but i have never tested it. Looks like you would need to set Parameter T088 [Analog out Sel] to 6, and then create a datalink to adjust Parameter T090 [Anlog Out Setpt].

 

[zmmarsad]

Thank you, Heliana! That solved the problem.

 

[zmmarsad]

Thank you everyone for your help. This project was pretty easy and straightforward. I struggled due to my 0 knowledge about PLC and drives. I will post the project steps if anyone ever needs them.

The project was to control the speed of a siemens drive that has no connection with PLC. Another problem was that I had no analog output card. So, I wanted to use the analog output of a PowerFlex 525 drive that is connected to the PLC. And finally, control the speed using an HMI.

1. Analog input goes to Siemens Micromaster 440 ports 3(analog input) and 4 (common).
2. Analog output goes to PowerFlex 525 ports 14(common) and 16(analog output).
3. Open drive properties>parameters. Set parameter 88 (t088) to "setpoint 0-10V".
4. Open drive definition>connection>output. Add parameter 90 (analog output setpoint) as output.
5. Create a new "Function Block Diagram" Routine. Add a scale function. Click on the scale function and enable input, raw input max, raw input min, engineering unit max, engineering unit min, and output. Make the "Limiting" value from 0 to 1 to limit its value within the range.
6. Your input will be a new tag you create, and your output will be your drive output.
7. Do your scaling as you prefer.
8. Download the program to the PLC and go online.
9. Open view>watch. Add your SCL input and output tags. Change the value of the input to observe how it affects the output.
10. Create an increment/decrement button on your HMI and use your newly created tag to control the speed of the siemens drive.