Reading value of [CO] in IEC850 variable

[GauravShukla]

Hi

I am using iec850 driver in one of our project command processing works fine when command is given from zenon scada however when command is given from any other location e.g IEC101 I am not able to log them to CEL which I understand because of [CO] being write only variable.is there any way I can read status of [CO] variable before this configuration we were using sicam 230 and it used to work fine with iec61850 driver of sicam 230

Regards
Gaurav shukla

[ursulak]

According the IEC61850 Standard the data attributes with Functional Constraint CO are "write only". So, an 850-client (like zenon iec850 driver) is allowed to write it to an IED, but not to read it from the IED. If another 850-client (or whatever) writes something to those IED not involving zenon then the iec850 driver does not get this information. 
If SICAM 230 was reading those attributes than it was behavior not compliant with the Standard (officially forbidden since Edition 2); zenon in old versions also was reading, but to pass the certifications and communicate with some very sensitive IEDs we had to change it in the driver. Some IEDs are treating any read of CO as the Select command; to do this is not compliant with the standard but find a manufacturer willing to fix it in the firmware in thousands of devices...

If the IED supports optionally possibilities like the 'Service Tracking' or presents the copies of originator in attributes with FC=ST (shall be equal the originator received with FC=CO) then you can evaluate it. 

If the IEC101 would communicate via zenon Process Gateway IEC870Slave then there also will be a trace of the command in zenon. 

[GauravShukla]

Thanks Ursula Kramarczyk for your quick support

much appreciated


Regards
Gaurav Shukla