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SLC5/04 1761-NET-ENI Powerflex 70 and 20-Comm-E

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I have been setup with an existing system with a SLC5/04 PLC (1747-L541C - OS401 Series C) that has a 1747-NET-ENI for Ethernet communications. Three Powerflex 70 drives are to be added, and have been supplied with 20-COMM-E modules. I have never set this up before, and looked at several examples using SLC5/05s, Micrologix PLCs, etc. I am pretty confused on this one. It looks like this is possible, however, the examples I have found in the Knowledgebase have MSG instructions, where a multihop tab is available in the MSG instruction. This is not an option in a MSG instruction for this processor in my program. I am using RSLogix 500 8.10. This whole setup was to be placed in a CompactLogix system, which would have been easier (and better), but messaging appears to be my only option unless I go to RIO or DeviceNet. I do not have a DeviceNet scanner, but there is a RIO scanner in the rack. My biggest problem is that the examples I have found in the 20-COMM-E manual for a SLC500 and a Micrologix do not match up with what I have. It has been awhile since I have messed with a SLC in this way, and the old headaches are coming back. I see that the MSG instructions in my SLC5/04 have control block lengths of 14, not the 51 shown in the examples. My SLC does not have the multi-hop tab in the MSG instruction. I have figured out that to reference the DN, ER and EN bits in the control blocks, I have to reference them by the bit address in the following way: N15:0/13 (not N15:0/DN as in the examples). I realize I have to setup mapping in the 1761-NET-ENI. Perhaps I do not need the multi-hop? I see some examples where it has been done for Micrologix/SLC, but like I said, the MSG instructions are different. I am concerned that I will find out this all does not work after the Ethernet drop is run to this system. The drives are on order, but have not arrived. Does anyone have some suggestions on this?

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#1 Make sure you have a hardwired means of stopping the VFDs if you plan to use SLC ethernet messaging for speed control. #2 Skip the 20-COMM-E modules and add a 4 channel analog card to the SLC for speed control. Use discrete I/O for control and status (may have to add digital I/O for this unless you already have spare points available). You won't be able to get as much data back and forth, but for most applications, a speed reference, start/stop, direction, and fault feedback (or "at speed") is enough. Analog control with hardwired signals will likely be more responsive than ethernet messaging even with only three drives. Another advantage is that you can use any drive in the future or in an emergency. Troubleshooting will be simpler too. #3 Check into upgrading the 5/04 to a 5/05. (My distributor is going to do this for us and it's apparently qualifying for the step forward program which includes a small discount.) What you're trying to do might be possible with the 5/04. We have a 5/05 doing it (with hardwired stop, and safety contactors) but the messaging had to slowed down and settings in the drive adjusted to tolerated the slow messaging. Trying to message to more than 6 drives too quickly caused problems. You might not see much of a problem with only three drives. Hope this helps, and be sure to post your results because I am sure someone else will be forced to try this too. Edited by OkiePC

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This is good to know.  One of my concerns is the slower communications. An explicit message is a much slower form of controlling the drives and is non deterministic.  The start/stop response is uncertain.  I can live with somewhat slower communications, since I am controlling 3 pumps, where a delay is not going to be as critical.<br /><br />Since I have to control 3 drives, there are 3 explicit message instructions per drive, and I would have to sequence these.<br /><br />The code is now to be placed into a ControlLogix PLC. The only issue I see is that the Powerflex 70-EC drives are not selectable from the version 13.04 version RSLogix5000 code. The CPU has version 13.x firmware, which is not hard to change. I have been told that the customer only has v13 RSLogix5000 software, which limits my options. They are unlikely to upgrade software anytime soon. I have been told that I could select a Powerflex 70-E during configuration in the program, since the 70-EC is not an option. I would have to disable keying as well. The drives are being shipped, so I have what I have. I am not sure if this will work yet. Edited by Patriot

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Do I understand correctly that you aren't looking for advice on the SLC-5/04 and 1761-NET-ENI anymore ? That was a barely-technically-possible approach. A ControlLogix controller is a much better platform for I/O control over EtherNet/IP. Version 13.x of RSLogix 5000 didn't have integration of drives at all (that I recall) so you're going to use the Generic Module object to connect to them over EtherNet/IP. You won't get the integrated DriveTools/Logix 5000 features, but that's OK; just use DriveTools or DriveExplorer separately. I'm a little concerned that your customer is ricocheting between control platforms so fast. Only a handful of very new controllers (like the CompactLogix L23 family and the 1756-L7x controllers) will not support the old v13 firmware so that should be OK.

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The customer has settled on utilizing a ControlLogix platform.  The existing PLC has v13 firmware, and the customer only has RSLogix5000 v13.  There are no plans for them to upgrade software soon.  After some research, I settled on the use of a generic profile as you described.  This went from being in a SLC to an existing CompactLogix (which for some odd reason had newer firmware), then to an existing ControlLogix with v13 firmware.  I am at least happy it is in a platform that will be easier to work with.  I no longer have to think about how I would have handled it in a SLC.  This is some good news to start the holiday season! Edited by Patriot

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