Does anyone have a sample of how to write explicit data to this module? I need to write to assembly 108 but wasn't sure how to set up the MSG instruction - Message Type, Service Code, Object Type, Object ID, Object Attribute, etc.
Maybe any sample to a 1734 module via devicenet would help.
Thanks!

Hi Mark,

Which controller are you using ? Sending explicit messages is relatively easy in the Logix-family controllers, and is possible but not easy in SLC-500 and PLC-5.

The 1734-VHSC user manual gives you some of the information you need to know on page 3-12, where is lays out the arrangement of the 54 bytes in Assembly 108.

It doesn't give you a couple of important facts, though. You can learn a lot about Explicit Messaging from the Knowbase document G16551, which I used as a reference when writing this post.

Here's what you need to know:

Service = 0x10 Set Attribute Single
Class = 0x04 Assembly
Instance = 0x6C (108 decimal) This configuration Assembly for the VHSC.
Attribute = 0x03 Assembly Data

Length = 54 bytes

Give that a try !