compact logix msg read from slc5/05

I am trying to read an integer from a SLC5/05 to a Compact Logix processor and am having trouble with the destination. I can't seem to figure out how to create an (INT) or (DINT) destination in hte Compact. Currently I have a set of timers that set a comm failure bit and the bit being the destination in the Compact is BOOL, but I can't figure out how to change to the correct type.

if you've already made - and used - the new tag in your program, then you'll usually have to go OFFLINE and jump through some extra hoops to change its type ...

usually it's easier just to create a new tag - and before you nail it down, click the little box shown below to set the type ...

I tried that, but when It compiles I get an error of data type must match argument...

are you confusing the data that actually gets TRANSFERED between the processors (specifically, the 16-bit INT) with the status bit (the BOOL) that you mentioned earlier? ...

can you post a screen shot of the rung - or something for us to look at? ...

ladder image

i have attached the image as a pdf. i am trying to read n7:0 as a decimal (1) to the HEARTBEAT_FROM _REMOTE.

the XIC and XIO instructions that you’re using aren’t capable of working with the full 16-bit INTeger N7:0 ...



try using HEART_BEAT_FROM_REMOTE.0 as the address for the XIC and the XIO ... depending on how you have the rest of the system set up, the “.0” on the end should tell the XIC and XIO to look at just the lowest bit within the INT ...

ncdkevin,

N7:0 is a SLC5/05 16-bit integer. I see from your program you are using the binary condition of HEARTBEAT_FROM_REMOTE to control the two timers in ControlLogix.

I'm a little rusty on ControlLogix tag assignment, but I think you need to ensure HEARTBEAT_FROM_REMOTE is assigned to only one bit of N7:0 and not the whole 16-bit word. Just a thought while Ron is away at the moment.

Can you post the tag assignment?

CeCo3

Edit update: Ron stated it better.

.0

Here is another one and as you can see, I still get the "slcread" references a tag of BOOL type...

not 100% sure that we're understanding each other ... the CompactLogix needs to read in the full 16-bit INT ... the only place that you need the ".0" is right over the XIC and the XIO ... you're not trying to enter that into the MSG are you? ... that won't work - because the MSG won't read down to the individual bit level ...

sorry I'm so short on time but I have a beautiful blue-eyed blonde sitting on my knee right now ...

You are reading a 16-bit integer from the SLC. You cannot read a single BOOL (bit).

You are OK to read this in to an INT tag in the CompactLogix, but your logic needs to inspect only 1 bit of the 16-bit integer.

I will assume that the Integer value in the SLC is set alternately to 0 or 1, or that you are driving bit 0 only on and off. Either way bit 0 will be toggling.

In your Compact, inspect bit 0 with :-

HEART_BEAT_FROM_REMOTE.0

the .0 at the end says "look at bit 0 of the INT".


How are you generating the Heartbeat in the SLC?
How often are you reading the Integer?
Does the SLC need to know that the Compact is reading the heart beat OK? (in other words do you need heartbeat functionality in both directions).

I always use a "free-running" heartbeat system between two PLCs like this, so that both PLCs can monitor the bits toggling.

PLC1
| Heartbeat_in_from_PLC2 Heartbeat_out_to_PLC2
|----| |----------------------------------( )--|
|

PLC2
| Heartbeat_in_from_PLC1 Heartbeat_out_to_PLC1
|----|/|----------------------------------( )--|


|

i am going to have a bit set to "1" being read from the Compact which will be doing the same type of format of a free running timer reseting itself so as not to set a done bit in the compact.

Question! It's possible to read from SLC 500 the I1 file using MSG?

Answer : Yes, no problem

This is the scenario. I have a ControlLogix using MSG to read I1 Data file in a SLC 500? When I configure the MSG instruction it says Invalid Element (Error).
Daba You said it is possible to do that. Tell me How>

Barbaman
Go to the www.ab.com then look for knowledgebase and you will find your answer there, search also here and on june 22nd 2007 ther is an answer to your question