controlling devicenet via MicroLogix 1500

Hello,

I have done the following:

Wired all drives to scanner/PLC rack with 120 ohm terminators in place.

Configured my network via RSNetWorx. I have 4 drives, all properly addressed. I can read drive keypad (run Hz) params using networx.

Configured my devicenet scanner with AutoAddress, all 4 drives are in and mapped.

Upload to scanner OK.

RSLogix I/O config OK.

Ladder code enabling scanner, OK.

Scanner is happy, showing code 63 only.

DeviceNet network is happy, all drives have steady PORT, MOD and NET A indicators.

PROBLEM:

I have the DeviceNet manual, the manual shows simple ladder code to start/stop the drive and set/read Hz.

I THINK I am addressing the drive right, but my 'O' file only shows only two words (O4.0, O4.1). I was expecting more, since Networx scanner config shows my memory map as: O:4.0 and O:4.1 as READ ONLY, and O4.2 and O4:3 as my first drive's memory addresses.

I thought I would send the STOP cmd to O:4.2/0 but am stuck here as Logix only expects O:4.0 or .1 addresses.

I'm stumped, please and thanks for help!!!

Tim

The 1769-SDN I/O configuration defaults to only memory for control and status, with zero I/O memory space.

I guess it's done that way to force you to consider how much memory you actually need, to conserve it for other modules.

Go to the "Adv. Config" in the I/O configuration window for the 1769-SDN, and you'll see the Input data sized for 66 words and the Output data sized for 2 words. Add to each of these the amount of Input and Output data you've mapped.

Whenever I use a 1769-SDN with a MicroLogix 1500, I get out the Installation Instructions and print out a copy of Page 17 to remind myself what the Status and Command words do.

Ken,

Very good, spot on!

I'm new to this, everything else seemed so easy to do.

While I got your attention, do you know of a good place to get sample code to read parameters from the drive, or is my DeviceNet manual, sectioned Explicit Messaging the place to go?

Thanks. Long night back East...

If your drives are PowerFlex 7-series, the easiest way to get data from them is to use the DataLink function. This will get you as many as eight monitoring parameters as part of the Input data image.

There should be some good messaging logic at samplecode.rockwellautomation.com.

What kind of drives are you using, and how much data do you need from each ?

I am using PowerFlex 400 series.

Actually, I'm stumped once more, I can set start, stop, run and direction, clear faults, etc. But I can't 'bump' the drive. Must I explicitly set Hz? If so, I can't figure out the word address for speed setpoint, again, DeviceNet manual states word O:1.2 in a MOV block, my translation would be O:4.2, which is the starting word for my command word.

Any more help and I'm grateful. Thanks again.

As you have seen, the PowerFlex 400 output data takes up 2 words of the Output data table for each drive.

The first word is the Command Word, with bitwise start/stop/jog commands.

The second word is the Reference Word, which is a value in tenths of Hz. A value of 150 in this Word, for example, will send the drive a reference value of 15.0 Hz.

The actual memory location depends on how you've mapped them. If you mapped the drive to O:2 and O:3. then the Reference Word is O:3.

You also need to set the drive to take its reference from the communication port, rather than from a front-panel interface or an analog input channel or a discrete setting. I think this is Parameter 38 in the drive.

Thanks, Ken. I understand.

If I set this param on the keypad, I suppose I can 'reset' it in logic to make a 'remote', 'local' interface on my HMI?

Thanks for all your help. I remapped my word, and I really think I understand the word I/O map now. Once I finish this project, I hope I can help someone out like you did for me. Thanks Again.

Tim

It's very common to have a discrete input to the drive select which speed reference the drive will use. This is often part of a "Hand / Off / Auto" control scheme, though the definitons of those modes are often subject to contention.

There is a good flowchart on page 1-28 of the PowerFlex 400 User Manual that describes speed reference selection.

http://literature.rockwellautomation.com/idc/groups/literature/documents/um/22c-um001_-en-p.pdf