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 in the observation, the ObsState of CSP.LMC could go in FAULT. Please note that this not refers to the case of the Tango Device has an internal error and the DevState goes in FAULT (see next for this case). To recover from this situation, the restart command is issued. This command will release also all the resources, taking the subarray in an EMPTY obstate.

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 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.