Bit of a strange situation, but Ignition is refusing to read a tag on a PLC that definitely exists. The full tag path is "[SIG01]DB5000,X0.0" (boolean tag).
Background:
I recently changed the structure of DB5000, after this Ignition refuses to read any tags inside of the DB. It always gives the error: [null, Bad("Bad_ConfigurationError: There is a problem with the configuration that affects the usefulness of the value."), Thu Apr 30 12:00:51 CEST 2026 (1777543251357)]. There are other tags also being read on the PLC (other DB's as well) and they work fine.
What I have tried:
- Restarting the OPC-UA module
- Removing the OPC Device and re-adding it (using same name)
- Connecting to PLC via Kepware to confirm PLC side - This works
- Added device 'test' in Ignition OPC using the same connection settings and adding the DB5000 tag - This works
- Exporting tags as JSON and deleting them from the designer, then importing them again
- Creating a seperate tag with the same DB5000 address
- Deleting the DB from PLC and moving to DB5001 - This works (but we need this to be DB5000)
- Going online and Deleting DB5000, then downloading it back to the PLC - This doesn't work
- Exported all tags in the gateway and searcing for [SIG01]DB5000 tags to ensure there are no duplicate tags
Details:
- Programmed in Simatic Manager
- Connected using S7-400 driver
- Port 102
- CPU slot nr 3 (S7-400 CPU with CP card)
- Ignition 8.1.37 (b2024013011)
- Siemens Comfort Panel accessing the same tags
I am hoping there is some kind of cache that is causing this issue, a cache that can be wipe without causing issues to other devices since this is a production system.
Tag export:
{
"name": "JDESI",
"typeId": "JDESI",
"tagType": "UdtInstance",
"tags": [
{
"name": "Control",
"tagType": "Folder",
"tags": [
{
"name": "ic_ReqManual",
"tagType": "AtomicTag"
},
{
"name": "ic_Planned",
"tagType": "AtomicTag"
},
{
"name": "ic_ReqAckAlarms",
"tagType": "AtomicTag"
},
{
"name": "ic_ReqAuto",
"tagType": "AtomicTag"
},
{
"name": "ic_ReqStop",
"tagType": "AtomicTag"
},
{
"valueSource": "opc",
"opcItemPath": "[SIG01]DB5000,X0.0",
"dataType": "Boolean",
"historyEnabled": false,
"name": "ic_Interlock",
"tagType": "AtomicTag"
},
{
"name": "ic_Warning",
"tagType": "AtomicTag"
},
{
"name": "ic_ReqStart",
"tagType": "AtomicTag"
},
{
"name": "ic_ReqReset",
"tagType": "AtomicTag"
}
]
},
{
"name": "Status",
"tagType": "Folder",
"tags": [
{
"valueSource": "opc",
"opcItemPath": "[SIG01]Mx151.2",
"name": "ps_Running",
"tagType": "AtomicTag"
},
{
"name": "ps_Consumables",
"tagType": "AtomicTag"
},
{
"name": "ps_Stopped",
"tagType": "AtomicTag"
},
{
"valueSource": "opc",
"opcItemPath": "[SIG01]Mx10000.6",
"opcServer": "Ignition OPC UA Server",
"name": "ps_Heartbeat",
"tagType": "AtomicTag"
},
{
"name": "ps_Ready",
"tagType": "AtomicTag"
},
{
"valueSource": "derived",
"deriveExpressionGetter": "{source}\u003d\u0027Connected\u0027",
"deriveExpressionSetter": "",
"sourceTagPath": "[System]Gateway/Devices/SIG01/Status",
"name": "ps_Connected",
"tagType": "AtomicTag"
},
{
"name": "ps_Idle",
"tagType": "AtomicTag"
},
{
"valueSource": "derived",
"deriveExpressionGetter": "!{source}",
"deriveExpressionSetter": "!{value}",
"sourceTagPath": "[.]ps_ModeManual",
"name": "ps_ModeAuto",
"tagType": "AtomicTag"
},
{
"name": "ps_MaintAM",
"tagType": "AtomicTag"
},
{
"name": "ps_LineDelay",
"tagType": "AtomicTag"
},
{
"name": "ps_MaintPM",
"tagType": "AtomicTag"
},
{
"valueSource": "opc",
"opcItemPath": "[SIG01]DB5000,X0.1",
"historyEnabled": false,
"opcServer": "Ignition OPC UA Server",
"name": "ps_BypassInterlock",
"tagType": "AtomicTag"
},
{
"valueSource": "opc",
"opcItemPath": "[SIG01]Mx139.0",
"name": "ps_ModeManual",
"tagType": "AtomicTag"
}
]
}
]
}