An interlock, safety rule, or rate limit is holding a control mode’s output.
| At a glance | |
|---|---|
| Code | 200 |
| Shown as | Policy Blocked |
| In the alarm list | The output’s name, then Blocked and the cause — Feed Pump Blocked, Feed Pump Blocked - Level Low — or, for a contact, the contact itself: Flow Switch - A I/Q (upcoming firmware) |
| Severity | Warning |
| Category | 2xx — Control-loop safety and policy |
| Clears | Automatically, when the blocking condition clears |
Something other than the mode’s own logic has stopped its output — most often an interlock such as a flow switch showing no flow or a low tank. The alarm is keyed to the output being held.
Where it can, the alarm names the cause instead of the generic title:
| Shown as | Cause |
|---|---|
| Flow Switch - A I/Q, External Stop - B C/Q (and similar) | That contact tripped the interlock: what it is — Flow Switch, Level Switch, External Stop, or Enable — then the IO-Link port and pin. Earlier firmware wrote Flow Sw. - Port A I/Q. |
| Output Blocked - Level Low, Level Low-Low, Level High, Level High-High | A sensor limit interlock tripped |
| Output Blocked | Another policy — a safety trip, a rate limit, or an interlock whose device was removed |
| Sensor Unreadable | A sensor behind an interlock cannot be read |
| Sensor Fault | The sensor reports its own measurement is unusable |
A safety trip or an exhausted rate limit shows the generic title, Policy Blocked. A latched safety trip does not clear when the reading recovers — see Latching trips.
Drives the output to its safe state and holds it there. The mode’s tile shows a padlock.