Problem writing value Factorytalk

[Nametag]

Hi

I have Factorytalk view ME on a PC. There is two plcs which it communicated with

PLC1 (1769-L32E)- communicates with no issue (read and write)

PLC2 (1769-L32E)- can read values but not write values
- Values which are read from the plc are updated with no issue
- Values which are written to the PLC give an error "Problem writing value 'TRUE' to item '[plc2]Test'"

As a test i created a bool "Test" in plc2, a numeric display and a pushbutton. If i change the value manually in the plc the numeric display will update with no issue. When the pushbutton is pressed i recieve the above error.

Has anyone come across this issue before?

Thanks

 

[Ken Roach]

In the RSLogix 5000 Tag Database, examine the "External Access" column for the tags in PLC2.

The default is "Read/Write" but you might have those specific tags configured for Read Only.

The fact that the error message says it's trying to write a value of "TRUE" to the tag suggests it's a BOOL datatype. Be sure the datatype in RSLogix 5000 matches the datatype in your FactoryTalk application.

 

[Nametag]

Thanks ken,


All tags are Read/Write and the tag i am trying to write to is indeed a BOOL. I have several INT that i try to write values into as well and get the error, but instead of "value of 'TRUE'" it is "Value of '2'" etc.

I think I may have gotten started fixing this issue. Sometimes PLC2 gives an error when trying to connect with rslogix5000. Something like all CIP connections are taken. I think this is where my issue lies. If i disconnect everything from the ethernet network and reconnect only plc2 and Factorytalk i can write to these tags

PLC2 Communicates with
A SQL database
2 HMIs (AutomationDirect)
1 SCADA computer (Factorytalk View ME)
PLC1

Is there anyway to tell how many connections each use?

 

[Ken Roach]

With that additional information I agree this is probably a resource problem rather than a configuration problem.

The rule of thumb with the 1756-L32E is that it can handle 32 CIP connections.

Some devices make more than one connection; FactoryTalk View can make up to five for different purposes (data logging, diagnostics, ordinary read/write, etc).

I/O connections, particularly analog modules, start chewing up your budget pretty fast too.

Have a look at the embedded Web pages in the 1769-L32E; there should be some good diagnostics there.