Adapter

During the writing of this report a very serious error was encountered with the `cable twist' which conducts the various communication cables from the devices attached to the rotator to the fixed telescope structure. It was found that the cable which guides this cable twist had broken, likely through wear and tear over the last 18 years since the installation. When this wire is broken a mechanism acts on a switch which activates an interlock and cuts the rotator power and amplifier. However, as in other cases the documentation does not show this limit switch and the TCS does not receive any specific warning, and the only sign on the TCS is that the rotator appears to have switched from remote control to local control, which pointed to a problem with the power supply or the amplifier of the rotator. This seriously complicated identifying the true problem. Also, repairing the cable took relatively long as it required a certain type of cable of sufficient length, and at some moment progress was delayed for many hours because the only cable we could get was $\sim$20cm short.

Although it is impossible to define potential problems of parts in the telescope that are not documented, we plan to make a general review of all the status parameters in the TCS to see if they are well defined and can be properly identified (e.g., the parameter for the status of a specific part is connected to a signal that can be traced to that part). In case this is not clear or ambiguous any error or warning status for this part reported by the TCS should note this to make people aware that the true problem might be hidden.