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G3200 using IEC61850 is not showing correct data from MB Slave when the slave is offline

Goals and Symptoms

G3200 and IEC61850 Client Software: How to detect if the Modbus Slave is Offline to prevent invalid values?

Facts and Changes

Having G3200 Firmware 1.4, PM820 meter connected to G3200 over RS485, some Siemens SCADA (as IEC61850 Client) connected to G3200 on Ethernet port.
If the communication between the G3200 and the PM820 is broken, then the values (last values of the PM820) are still available over the G3200. In this case, would be better to have all PM820 data become invalid. Is there a possibility to change this in the CID file or in the G3200 firmware, or is it impossible?

Causes and Fixes

Current Implementation of G3200 doesn't support updating IEC 61850 database when connected device is Offline.
SCADA connected to G3200 should check the values of LLN0 and LPHD before reading the values. If It finds LLN0.ST.Mod = 5(OFF) then it should not consider reading values from the Modbus device.
This was the G3200 project decision to implement the same functionality as in ECI 850 gateway, so, it is NOT possible to change now.

Please find below the solution for SCADA (or any other IEC61850 Client software) in which we can find if the connected Modbus device is Online or Offline.

LLN0 and LPHD are the two logical nodes dedicated for physical device health and status.

Case1: When connected device is "Online"
LPHD1.ST.PhyHealth = 1(OK)
LLN0.ST.Mod = 1(ON)

Case2: When connected device is "Offline"
LPHD1.ST.PhyHealth = 3(Alarm)
LLN0.ST.Mod = 5(OFF)

G3200 updates IEC 61850 database of the device if and only if device is Online.
Then, it reads the data from device using Modbus and update IEC 61850 database.
If devices gets disconnected, Measures, Quality and Timestamp won't be updated. However, the above mentioned nodes: "LPHD1.ST.PhyHealth" and "LLN0.ST.Mod" should be updated and their values could serve as device status monitoring.

Created on 13th MAY 2013 by
Adrian Dicea
Global Expert Technical Support Engineer - Support Prime PSE / EGX

Legacy KB System (APS) Data: RESL211440 V1.0
Related ranges: G3200
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