Workarounds for reading bit arrays over MSGs

Dan123

Member
Join Date
Sep 2014
Location
California
Posts
17
I have a ControlLogix L65 controller, and I'm trying to read some alarm status information from a BMS gateway device. The problem is that this data is contained in a bit array, and you can't read BOOLs using MSGs. The only answers I've found are that the BOOLs on the source device must be converted to integer. It would be a considerable amount of hassle if I needed to modify the BMS device configuration (never worked with it, probably would impact other systems, and it's likely nobody at this site knows anything about the configuration of this device, so it'd be a whole thing), so I would very much prefer NOT having to do this. Is there any possible way to have the source element on a CIP Data Table Read be a bit array? I've tried writing to DINTs, but no matter how I address it I get the '2107' data type mismatch error.
 
There is no way to address a BOOL tag or element of a BOOL array with a MSG instruction in ControlLogix.

This is really a commercial decision; the number of customers who would code themselves into a corner by attempting to use one P/C Tag or MSG per bit is an order of magnitude higher than the number of customers who have un-changeable systems coded to use BOOL[x] arrays for external data access.

What make and model is the BMS system ? Is it a "Burner" Management System or a "Building" Management system ?
 
Yeah I understand the reasoning, I was just hoping to save myself some work. It's a building management system (or at least a component of it) -- connected to an SMC QuickServer. I'll be able to look through their documentation and figure it out, it's more the logistics of getting involved with this system that I wanted to avoid.
 

Similar Topics

PLC programming software 'wears out' before PLC hardware. Operating systems are upgraded or abandon by their originators. PLC software...
Replies
17
Views
22,039
Dear all, I don't know why setup of password became challenging and weird. After setting up the password and try to upload the ladder from the plc...
Replies
3
Views
97
hi all, i have a plc i need to get info from for a site im working on: I have a 1764 Micro Logix 1500 LSP Series C (See Attached Image) im...
Replies
2
Views
354
Hi to everybody. I need to read the first 12 characters of the message that a barcode reader sends to the ascii card (1734-rs232 ascii) and I...
Replies
8
Views
686
Hey, I have a PowerMonitor1000 I'm using for voltage control. The problem is it doesn't seem to read voltage until it gets to about 200V...
Replies
0
Views
355
Back
Top Bottom