Repacing some SLC 500 with CompactLogix-Would you use 1769-OF8C or 1769-OF8V in Panel

Cydog

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Feb 2018

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• May 12, 2020

• #1

Good Afternoon ,


I'm going to be replacing a few SLC 500 PLC's with CompactLogix this year. I would like to keep the PowerFlex 70 Drives in the panels , but eliminate Devicenet and go with analog controls for now. The new PLC and the old drives will be in the same panel.


My question is , would you guys use an Analog 0-10 VDC 1769-OF8V or 4-20 ma 1769-OF8C in the cabinet to control speed ?


Thanks so much ,

 

Bullzi

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• May 12, 2020

• #2

I always use 4-20mA for my analog. A voltage signal can be affected by wiring distance and even induced voltage from other devices in the panel.

 

GaryS

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• May 12, 2020

• #3

If you are making a change anyway why not change the drives to ethernet it's jus a card swap in the drive
I think it would be quicker and simpler to setup

 

janner_10

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• May 13, 2020

• #4

As above - keep it nice and neat and change to E/IP

 

Cydog

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• May 13, 2020

• #5

Thanks . Yes , I did that with a project early last yesr , but I had the luxury of replacing all the drives with Powerflex 525. I used ethernet with those , but keeping these old Powerflex 70 drives , they just seem so difficult to get around . We are a 24/7 plant I want the maintenance staff to be able to change these out fairly easily .


Thanks for your advice ,

 

Helliana

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Louisiana

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• May 13, 2020

• #6

For drives inside the same cabinet, I prefer to stick with voltage signals. Voltage is easier for most people to troubleshoot since you don't have to break the circuit or have a more expensive meter capable of measuring mA current.

 

Robobob

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• May 13, 2020

• #7

Just replace the 20-COMM-D (DeviceNet) with a 20-COMM-E (E/IP) or a 20-COMM-ER (Dual Port)in the drive. I think remapping the I/O to and from the drive would be a lot less work that converting the signals to Digital and Analog I/O. Hardware and software wise.