CSP LMC Troubleshooting

Since the CSP LMC is the entry point of all the CSP sub-elements, the State, ObsState and HealthState of the CSP LMC have to reflect also the State, ObsState and HealthState of all the CSP subsystems. In order to identify the cause of a particular condition of the CSP LMC, the starting point is to understand the subsystems status. For doing that, we have defined some tables to link the status of the CSP LMC and the one of the subsystems.

Recover from a FAULT obsState

If something goes wrong with the observation, the obsState of the Low CSP.LMC Subarray could transition to FAULT. Note that this condition differs from the one where the State of a TANGO Device is in FAULT (see below). To recover from this situation, issue the Restart command. This command will release also all the resources, bringing the subarray into an EMPTY obsState.

The sequence of operations and responses is:

csp_sub1.obsstate -> FAULT

csp_sub1.restart()

csp_sub1.commandResult -> ('restart', '1')
csp_sub1.obsstate -> RESTARTING
csp_sub1.commandResult -> ('restart', '0')
csp_sub1.obsstate -> EMPTY

Recover from a FAULT State

When an internal error occours in the Low CSP.LMC Subarray or in the Controller, the DevState (State) of the device can transition to FAULT. To recover from this condition, the Reset command needs to be issued. If executed successfully, this command will restore the device to a state determined by the aggregation of the states of its subordinate systems. The same applies to the observing mode for the CSP Subarray.

Please be aware that when the Low CBF device state is DISABLED, the state of the corresponding CSP LMC device is indicated as FAULT. Even after executing the Reset command, the CSP LMC device remains in the FAULT state.

In such a scenario, it’s advisable to first set the CSP LMC device’s AdminMode to OFFLINE, then switch it back to ONLINE, and verify whether the state of both the Low CBF device and the CSP LMC device has changed.