Powerflex 525 - one input, two functions

ASF

Lifetime Supporting Member
Join Date
Jun 2012
Location
Australia
Posts
3,907
Hi all,


I have a powerflex 525 drive controlled over ethernet, which also needs a 'local-off-PLC' switch hardwired in to manually run the drive in the event of a PLC failure. I've wired the "local" contact into the drive as a "jog" input, but the problem I have is that my drive AOI sees the drive running when it doesn't think it should be, and sends the drive a stop command, which according to the manual, overrides the jog command.


I could change my AOI, but I don't want to do that as it's used in other places.
I can bridge the "Local" switch to a second input, and configure that input to switch the start source of the drive to terminals, but that involves another drawing revision, which is a little painful with this client
I wish I could configure one input to have two functions, but I don't believe that's possible with the PF525



So basically, I'm wondering if anyone here has any creative ideas to get this to work using only drive parameters, so I can avoid some tedious drawing updates or having two separate AOI's to maintain?
 
Hi,


Is it possible to change how the AOI sees the drive running?
Can you add an extra rung of code with an OTE for drive running that only comes on when not Jogging?


Ian
 
Is it possible to change how the AOI sees the drive running?
Can you add an extra rung of code with an OTE for drive running that only comes on when not Jogging?
The AOI does all of that internally. I just pass it the whole input data image from the drive, and it does its thing, and passes me back the whole output data image. Means that I don't have to do any mapping at all (except the input and output data tags in the AOI instance), but also means that I can't change anything about how it sees "drive running" without changing the whole AOI
Can you run an input from the switch back to your PLC. When not in PLC mode, disable the AOI?
That was my initial thought, but if I do that I lose all of the other visibility and alarm functionality etc from that drive. It works, but not really ideal.
If the PLC is off due to failure, how is the AOI executing the stop command?
Valid point, and you're right - if I unplug the ethernet cable from the drive then I don't have the issue. Same would apply if the PLC wasn't in run mode or had otherwise failed. So for the purposes for which it was designed, it's actually just fine. But the customer wants to be able to periodically test all of their failure-handling scenarios on maintenance shutdowns, and so the function will need to work for the purposes of a test even with the PLC online.
You can set the PF525 to run in AUTO or Man Mode using digital input
but if the stop command is sent over ethernet then it wont run.
Yes, that's the problem. The PLC is always going to send the stop command, and the only way to have the drive ignore it is to change the start source off Comms.


Guess I'm doing another drawing revision!
 
Aha!


t062 >> 40

"Purge" - Starts the drive at A433 [Purge Frequency] regardless of the selected control source. Supersedes the keypad Control function as well as any other control command to take control of the drive. Purge can occur, and is operational, at any time whether the drive is running or stopped regardless of the selected logic source selection. If a valid stop (other than from comms or SW enable) is present, the drive will not start on the purge input transition.
I'll have to test it out when I get to site next week, but it looks like it's exactly what I'm after!
 

Similar Topics

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...
Replies
9
Views
3,928
I set up a Powerflex 525 drive to follow a signal from a master conveyor's encoder. The follower motor has an encoder wired back to the 525...
Replies
7
Views
3,952
Hi guys, So we had a network crash and the lines wouldn't start. This created a new project for me to add a selector switch and a pot to each...
Replies
9
Views
7,963
New to vfds. I put in parameters. IP, but I get ethernet flashing and link solid. What did I do wrong?
Replies
1
Views
15
Are the N files in the 525 the same as the 40p for ethernet? (E-Comm card) I have used 40P with Micrologix 1400 Messaging but don't see the N...
Replies
1
Views
65
Back
Top Bottom