Experimental Physics and
Industrial Control System

We are starting to examine the use of ControlLogix PLCs at IPNS and I am looking at Kay’s driver for Ethernet/IP.  We now have our first test setup going and we are looking at some of the subtleties with how to access various types of tags.  I am very novice with any PLC so please forgive my awkward use of terminology. 

 

It appears that the only tags that are accessible to the EPICS driver are ones provided at the controller level ( in RSLogix 5000 App).  Is this correct?

 

We have been able to access inputs (ai & bi) OK but have been having some trouble with binary outs.  So far we have avoided arrays altogether.  We have a binary out module ( relay out I believe ).  We can control an output of this directly using the base tag Local:2:O.Data[3] with a binary output record.  However, when we create another tag which aliases Local:2:O.Data[3] and point the record at this, we can turn the output on but cannot turn it off.  I have an EPICS screen that allows me to change the value and monitor the RVAL field.  Here I see the new value (0) temporarily reflected in the RVAL &VAL fields but then it goes back to 1.  No change is seen in RSLogix 5000.  We can reset the Value with RSLogix 5000 and repeat the process.  The same effect is seen for any “soft” tag.  BTW the soft records that I have are type BOOL.

 

Any ideas?

 

 

John Hammonds 

Data Acquisition Systems Manager

Intense Pulsed Neutron Source

[email protected]

(630)252-5317