Why can't HOPC read backup BRC410 modstatus information on an Infi 90 network
Hi, If possible, I was hoping for some insight regarding obtaining MODSTATUS information on a backup MFP11/12 controller on an INFI 90 network via an IET800 as OPC data. To clarify, I am successfully receiving the Primary Controller status information eg. Address in HOPC configuration -> Loop 1, PCU 1, Module 3 Block 0 (1,1,3,0) through to HOPC 6 but I am failing to get the MODSTATUS information from any backup controller (eg 1,1,4,0).
When I run a report on Composer, I see the module status information for both controllers – in this instance the PC running composer is retrieving the information via a serial link to the INfi 90 network, not through the IET800s. It seems the IET800 is not passing the OPC data from the Controllers in slot 4 but slot 3 works fine. This is the same for the few redundant pair BRC410s we have in place as well. All other OPC tags read just fine through to HOPC.
Would anyone have any idea why this might be the case.
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As far as I know, the creation of a N90STA/MODSTAT tag for a redundant Harmony controller is still invalid in the Harmony enviroment and can ultimately cause module redlight and communications issues. There are several bulletins discussing this issue (WE-DOC-3BUA001225R0001 is the most recent, 2011) but basically N90STA/MODSTAT tags should only be configured for
-Both the primary and backup NPM (address 0 and 1)
-IET/ICI modules (always module address 2)
-Only the primary module address for redundant pairs of controllers
-Both the primary and backup bridge/gateway nodes, but only for the ‘local’ side of any bridge/gateway nodes (always module address 2).
The bulletins also include the procedure for removing incorrectly defined N90STA/MODSTAT tags from the system.
If you want to explicitly alarm the backup module status you can use the FC95(MODST) to extract the backup status from the PRIMARY controller status bytes.
Regarding the difference in behaviour between HOPC and Composer. Composer is polling and communicating with each module directly to retrieve the module status data, so will behave differently to a MODSTAT tag.