When the Geo SCADA Expert server has not been in communications with an IEC 60870-5 outstation for some time, it performs an Establishment Phase scan, rather than the usual Primary Phase scan (see Establishment Phase in the Geo SCADA Expert Guide to Advanced Drivers).
Use the fields within the Communications Procedure section of the IEC 60870-5 tab to specify the operations that the IEC 60870-5 driver performs during an Establishment Phase scan:
- Global Interrogation on Establishment—Select this check box if Geo SCADA Expert is to request current point data from the outstation as soon as it establishes communications with that outstation. Thereafter, the Geo SCADA Expert requests current point data at the next scheduled interval.
Clear the check box if the server is to only request the outstation’s current point data at the next scheduled interval (see Configure the Station and Group Interrogation Intervals).
- Counter Interrogation on Establishment—Select this check box if Geo SCADA Expert is to request counter point values from the outstation as soon as it establishes communications with that outstation. Thereafter, the Geo SCADA Expert requests counter data at the next scheduled interval.
Clear the check box if the server is to only request counter data at the next scheduled interval (see Configure the Counter Interrogation Intervals).
- Set Clock—Select this check box if Geo SCADA Expert is to set the outstation’s clock. The clock will be set as soon as Geo SCADA Expert establishes communications with the outstation. Thereafter, Geo SCADA Expert will set the outstation’s clock at the next scheduled interval (as specified on the Channel Form
The Clock Set Failed status attribute indicates whether Geo SCADA Expert’s latest attempt to set the outstation’s clock succeeded (see IEC 60870-5 Specific Status Display Attributes).
Clear the check box if the outstation does not support clock setting or is receiving its time from another source (such as another Controlling Station, or a GPS clock).
- Summer Time Flag—Select this check box if the outstation supports the summer time bit for clock synchronization and event time stamping. Clear the check box if the Summer Time Flag does not apply to the outstation.
- Max Concurrent Requests—Use to specify the maximum acceptable number of active concurrent requests that the outstation can handle. An active request is a request, such as a control, that Geo SCADA Expert has sent to the outstation, but for which Geo SCADA Expert has not yet received a response to indicate that the outstation has completed the request.
- Specify 1 if the outstation can only process one request at a time; Geo SCADA Expert will queue further requests until it receives confirmation that the outstation has completed the currently active request.
- Specify 0 (zero) to remove the upper limit on consecutive requests. Should the number of active concurrent requests be such that the outstation does not have space in its queue for any more requests, the outstation will reject any further requests by sending a suitable protocol response. Should this occur, Geo SCADA Expert will queue the requests until the outstation acknowledges an active request.