run a vfd to plc

janardhan26reddy

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• Apr 24, 2012

• #1

I want to run a VFD through plc signals....how many inputs signals to need to run vfd?i.e, START,STOP,RUN FORWRD & REVERSE....

 

HJTRBO

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• Apr 24, 2012

• #2

1
Set up the drive to take the input as "run forward" or "run reverse".
Some drives may require an enable signal so that can be looped off the drives 24V supply if using current sinking inputs.
Don't forget your safety requirements!

 

MarkNightingale

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• Apr 24, 2012

• #3

It would help us to help you if you gave us more information.

What PLC?

What VFD?

What communication do you have available between PLC and VFD?

Mark

 

nonuke

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• Apr 24, 2012

• #4

In most VFD's I have worked, you need 2 outputs from the PLC (enable+CW and CCW)and 1 Input to the PLC to tell the plc the drive is OK. You will also need an emergency stop signal to the VFD which is done most of the times with hardwires.

 

Brijm

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• Apr 24, 2012

• #5

janardhan26reddy said:

I want to run a VFD through plc signals....how many inputs signals to need to run vfd?i.e, START,STOP,RUN FORWRD & REVERSE....

Click to expand...

Depends on what you want to do... Minimum of 1 (2 for Fwd/Rev), but you may use all of them.

Does the PLC need to determine/change the speed of the drive?
If the PLC crashes, how important is it that the drive stops? (If it is motion, then you will probably want 3-Wire control)

To hardwire the drive, the PLC is of little importance (Although I would probably recommend relay type outputs to a drive.)

 

rikcando

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• Apr 24, 2012

• #6

Although I would probably recommend relay type outputs to a drive.

Click to expand...

Definitely agree.

I would also expect a fault reset output to the drive.

 

DickDV

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• Apr 24, 2012

• #7

You will need one analog output for speed (frequency) unless you are going to use fixed speeds or MOP (floating point control).

Not enough data given to be very specific.

 

nightex

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• Apr 24, 2012

• #8

com (+24) to plc relays, start, reverse. Three wires.

 

rdrast

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• Apr 25, 2012

• #9

TLI.
Application specific.

For the record, I control most all VFD's from the PLC with 3 wires.

Two dry contact for E-stop, and one for ControlNet.

 

Tom Jenkins

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• Apr 25, 2012

• #10

RTFM

Whenever I start with new equipment I get the manual, look at the features and general description, and then I look at the wiring diagrams. These will tell you the various functions available. Then, based on the job you are trying to do, you can decide which of those you want to use, and then how to make that happen based on the wiring diagram. This workd for VFDs, and motor starters, and valve operators, and PLCs and .......

 

seppoalanen

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Jan 2003

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Finland

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• Apr 25, 2012

• #11

As "rdrast", I'm using only filed bus control as Profibus, Device Net, Profnet, Ethet Cat etc.
I can get and animate Process data from VFD as: Fault-ID, Power, Current, Torque etc..
Finally, field bus cost less than BIO/AIO control and gives much more usability.