Write single bit from Micro820 to SLC5

[bigsteve]

Hi, I've got a Micro820 that I am using to create some menus and handle an alarm buzzer for a Panelview 800 HMI. I also need it to communicate with an SLC5/05. I found a UDFB for connected components that can write a file over, but it handles it at the word (? I think I have the terminology correct) level; it will send, for example, B3:0 as 16 bits to B3:0/0 to B3:0/15. There are some cases where I need to send a single bit (e.g. TRUE to B3:0/8), not the whole block.



I am going through the UDFB code, and it looks like it does the transmission by using the MSG_CIPGENERIC command, combined with a file block that references PCCC - 'Byte size', 'file number', the 'Binary file type' is 133, etc. Does anyone know of a reference file that can point me towards how this PCCC communication would work?



Thanks!

 

[Saffa]

Can you just write a whole word to a spare address range in the SLC, then modify the SLC code to look at the specific single bit? That's how I'd do it anyway. I'm pretty sure that a single 16 bit word / int is the smallest part of a file you can write in the SLC / Micro family

 

[geniusintraining]

Write single bit

How far away are they? if not far and you have a spare input/output just run a wire and use a digital I/O

The issue I have had is addressing a word in the 800's (CCW), I still did not find a way how to address a output word

 

[damica1]

I may not understand what your needs are so forgive me if that is the case.

In CCW V12 let's say you have a "Word" Datatype and the variable name is "Sample"
and you want to (MOV) bit 3 of that word, you would use Sample.3 as the source and this
will just move BIT # 3

 

[daba]

You cannot message anything smaller than a single integer.

Saffa's method is the only way you will be able to transfer a single bit, i.e. as part of a word.