DEM instruction in SLC 505

Hi
Im working with the explicit message instruction "DEM" in a SLC 505 for the first time, and my question is if anybody knows if i can change the node adress dynamicly. As far as i can see, the target node adress is static, but if somebody knows a "workaround" i would love to hear about it!!

Why not create a second message instruction with each on a conditional rung.

Because i want to keep the program as simple as possible. (I have approx. 30 nodes on my network)

What is the new DEM instrucion?
I have CPR version 7 and it is not in my SLC Help.
Where did you find out about this instruction?

The DEM instruction is a "Devicenet Explicit message" instruction


regards

Kolberg

SNK said:

What is the new DEM instrucion?
I have CPR version 7 and it is not in my SLC Help.
Where did you find out about this instruction?

Click to expand...

See PDF

It is offered in CPR v7.1. That is why I can't see it!

The DEM, CEM, and EEM instructions for CIP Explicit Messages on DeviceNet, ControlNet, and EtherNet/IP networks were introduced in SLC-5/03,04,05 firmware OS302 Series C FRN 10.

The specifics of the control block are documented in the newest revision of the Instruction Set Reference for the SLC modular controllers, which is Publication number 1747-RM001E.

The DEM target MAC ID (DeviceNet Node Number) is in the low byte of Word 08 of the command block.

I recommend storing the target MAC ID number in an Integer register, and using a Masked Move (MVM) instruction with a mask of 0x00FF to move it into the low byte of Word 08.

If you have a new 1747-SDN Series C module, be sure you have firmware 8.005 because of a possible initialization data problem in the earlier firmware for the Series C module.

I recently posted a 5-rung SLC-500 routine using a single DEM instruction to read multiple parameters out of a single device, which might serve as an example for your application.

On MrPLC: File ID# 748

The same file will be on the RA Samplecode website in a couple of days.