Controlling Powerflex drive on ML1400 from L33E CompactLogix

All,

I am setting up some systems and am trying to utilize BOOL Inputs on my CompactLogix to trigger a change in frequency command on a PowerFlex drive programmed in a MicroLogix 1400 (connected via Ethernet/IP). I know I want to write from my CompactLogix to my Micrologix, any tips on where to start on this one?

PLC_ENG

The easiest solution would be to use the message instructions to send a control data type to the Micrologix. The messaging manual for Logix5000 is located here:

http://literature.rockwellautomation.com/idc/groups/literature/documents/pm/1756-pm012_-en-p.pdf

There are two common issues i see with people setting up messages for the first time:
1) Getting the communication path correct.
2) Making sure you are using the same data type on BOTH PLCs. For example, if you are writing to B3 or N7 on the micrologix1400, the tag in the Compactlogix needs to be of the datatype INT (not a the default of a DINT).

Also, since you are controlling a motor, you need to take into account of what to do if communication is lost. It may be a good idea to put in a heartbeat signal so you can tell if communication is lost so you can shut down the drive.

This sounds a little backwards.

Is the PowerFlex networked to the MicroLogix, or hard-wired to the MicroLogix ?

CompactLogix and ControlLogix controllers are designed and advertised and supported to perform I/O connections over Ethernet.

The MicroLogix can do a half-baked messaging-based control of a PowerFlex, but it's not a recommended method.

(and welcome to the Forum ! We'll try to be gentle.)

I am tying two hoppers into a piece of existing equipment, there are two hoppers that have ML1400 and came with 3rd party written code. I wrote the code for the main piece of equipment on CompactLogix. The powerflex for the elevator drive is already programmed on the Micrologix controller. I just want to tap in and manipulate it based on a condition (in my compactlogix).

Thank you for the welcome. I am a long time reader, first time poster

I am going to exercise a colossal amount of restraint and will refrain from commenting further on the existing application.

Fortunately, the MSG instruction is fairly straightforward in the CompactLogix.

You'll be using INT datatypes when you write to a MicroLogix; go ahead and pack your data from the BOOLs into bits of an INT type tag or tag array.

When you create a MSG instruction and a Controller-scope MESSAGE type control tag, you'll select "SLC Typed Write" as the message type.

The destination element is the ordinary MicroLogix style data table address, like "N10:0". If you need more than one word in order to send more data or a watchdog value, go ahead and make the length larger than 1 Word. Ethernet is so fast and has such a large amount of overhead that sending one word or fifty words takes about the same amount of time.

The CIP Path is straightforward; it's the Ethernet Port number (2) and the IP address of the MicroLogix, separated by a comma.

You do not put the MicroLogix into the I/O tree of the CompactLogix, by the way.

Thank you Ken....I appreciate the restraint. This is one of those work with what you are given scenarios. The same CompactLogix I am using on many PowerFlex 525s. I appreciate the tips.