SLC 5/05 to Powerflex 700 vfd

Hi, has anyone ever connected a slc 5/05 to a powerflex 700 vfd via the ethernet port on processor. The vfd has a 20-comm-e communication module. I want to control the vfd from the slc and just wondering how to setup the message block in the ladder logic.
Thanks
MD

mdwyer39 said:

Hi, has anyone ever connected a slc 5/05 to a powerflex 700 vfd via the ethernet port on processor. The vfd has a 20-comm-e communication module. I want to control the vfd from the slc and just wondering how to setup the message block in the ladder logic.
Thanks
MD

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If I am not mistaken, you cannot use a SLC 5/05 as an ethernet I/P scanner.

Your application would require Contrologix, 1756-ENBT and RsNetworx for EthernetIP

Ian

RSNetWorx for Ethernet/IP would not necessarily be needed if you are working with version 15 of RSLogix 5000. In this version of the software, I believe that you can set up communications with the drive using the IO configuration tree and DriveExecutive Lite (which is bundled with certain flavors of RSLogix 5000).

rgurin said:

RSNetWorx for Ethernet/IP would not necessarily be needed if you are working with version 15 of RSLogix 5000. In this version of the software, I believe that you can set up communications with the drive using the IO configuration tree and DriveExecutive Lite (which is bundled with certain flavors of RSLogix 5000).

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Cool,

we have messed around with EthernetI/P and PowerFlex drives, but I personally have not done a drive using Enet only Dnet and Cnet. All I am sort of sure of is a SLC 5/05 EthernetIp PLC cannot control the PowerFlex via ethernet.

Ian

curlyandshemp:

You might be right about the SLC not communicating with the PowerFlex directly over Ethernet/IP. I was trying to look some things up on the Rockwell Web site about this, but I'm having computer issues.

Anyhow, I believe that the SLCs use the PCCC protocol for Ethernet/IP, while the PowerFlex adapter (and ControlLogix family) use CIP. Therefore, the SLC and drive might not be speaking the same language...

Rick

Here's the deal:

SLC-5/05 controllers CANNOT control I/O modules on Ethernet, because they do not implement the Class 1 I/O connection set for EtherNet/IP protocol. For I/O on Ethernet, you need a ControlLogix family controller.

The drives interfaces (20-COMM-E, 22-COMM-E, 1203-EN1) are special cases. They include a "register object" that appears like an SLC integer file, which you can send MSG instructions to, which will start and stop the drive and give it speed references.

I never recommend this method. MSG instructions are inherently not the way to control I/O, no matter how much you might want them to be.

But it does work. If you are familiar with Ethernet messaging in the SLC, and you aren't concerned about speed, you can run the drive from the SLC.

I still strongly recommend DeviceNet or the 1203-SM1 SCANport module to run a small number of drives from an SLC controller.

Resources include the 20COMM-UM10 User Manual for the 20-COMM-E (see page C-16) and RA Knowledgebase document A83250243.

Ken,

When I saw you had responded to this post I said to myself "The Guru speaks, what the master says IS the way it is".

I was unaware this could be done with a SLC. I guess the only danger is, once a MSG is sent to a drive and IF the SLC crashes, can or will the drive stop?

Ian

Be at peace, child of automation.

There is a timeout value associated with this "Register Object" in the 20-COMM-E. Page C-6 of the User Manual describes it as the Register object's class attribute 100, the "Control Timeout". I think it's zero to start with, and needs to be set to a nonzero value before you can use this control method. That value is also accessible using the PCCC Object, as "integer register" N42:3 (see page C-16).

The real performance drawback is that the SLC-5/05 Ethernet port is served by the CPU itself, so if you have a long program scan time or the port is very busy serving HMI traffic, you can have a small delay in acting on your MSG instructions to the drive.

I have never taken the time to write a full application technote, including performance analysis, for this sort of application because that would be tacitly endorsing it, which I don't.

If you are very concerned about the I/O reliability of the Ethernet connection, you could just hardwire the Start/Stop connection and send the speed value by itself.

Perfect thanks Ken,

The info you provided is exactly what I was looking for. I too noticed the comment about the control timeout value to be non-zero. I'll be sure to change that. As for the start/stop control, it is hardwired and the message block will only be used for speed reference.

Thanks again,
MD

mdwyer39 said:

Perfect thanks Ken,

The info you provided is exactly what I was looking for. I too noticed the comment about the control timeout value to be non-zero. I'll be sure to change that. As for the start/stop control, it is hardwired and the message block will only be used for speed reference.

Thanks again,
MD

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If that is the case, then you may want to rethink the reason for going Ethernet. In my experience, the main advantage for using a communication network for controlling 'stuff', is the cost savings from not having to run conduit with multiple wires to the 'stuff'.

If you are considering running wires to the drive for digital I/O and then use Ethernet for the speed reference, use analog outputs instead, way more reliable.

Ian

Ken Roach said:

Be at peace, child of automation.

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Nice Phrase

Ken, you sound like you should be on Star Trek

504bloke said:

Nice Phrase

Ken, you sound like you should be on Star Trek

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Once you snatch the rung of logic from his hand, you elevate to the next level Grasshopper

Ian

curlyandshemp said:

Once you snatch the rung of logic from his hand, you elevate to the next level Grasshopper

Ian

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Hey now that brings back some tv memories!

504bloke said:

Hey now that brings back some tv memories!

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That is because Keye Luke's grandson Key Switch is associated with every PLC

Ian