CMX/PBM/CKL – Linking to a bus with only one undisturbed unit
A description of this resolution:
- Work around the effects of the problem as follows:
To delete the incorrect entries, the subscriber whose mounting position code was entered incorrectly must first be unlinked (in the example this is the coupling CMX). To unlink the subscriber, the service station must be ‘plugged’ into either the unit to be unlinked or in another island. Next the subscriber must be linked from one of the newly linked subscribers. In the case of a coupling CMX further linking from another island is also required if the unit is not the only subscriber on the SA bus.
If the service station cannot be replugged, the units with the incorrect entries must be initialized by mounting position intializing and then reconnected to the power supply. The remaining unit must then be reset by removing and replacing the fuse which results in this unit being transferred to the subscriber lists of the other units. Then the units can be linked once more.
By resetting the newly linked redundant unit the correct bus traffic can be restored as the missing subscriber has been transferred. If the subscriber list on the redundant unit is incorrect, proceed as under Point 1.
"CMX/PBM/CKL – Linking to a bus with only one undisturbed unit" resolves the following:
When links are made to a bus with only one unit or only one undisturbed unit, incorrect subscriber lists and disturbed bus traffic can occur.
The only existing or only undisturbed unit is already linked. No other units are entered in its subscriber list or all other subscribers are listed as being disturbed (e. g. after an exchange). The units to be linked only received their voltage supply after the first unit. The units to be linked may be new units to be linked or exchanged / initialized modules.
A coupling CMX without redundancy, with an A-bus that is not yet linked to any units.
A coupling CMX without redundancy, with an A-bus that only has one unit linked, but that unit must be exchanged.
The units to be linked contain RUPI Version 1.02. With the new RUPI Version 1.03 these problems do not occur.
The subscriber lists of the linked units are incorrect. In the main processing unit, the mounting position code (EPC) of the redundant linked unit has been entered in the place of the mounting position code of the linking (not exchanged) unit. In the secondary processing unit of the newly linked unit the entry of the linking unit remains empty.
If the linked unit does not have a redundancy partner, FFFFh appears in the relevant part of the mounting position code (displayed by the CONFIN function “Read bus subscriber list” as PBM or CKL without mounting position code).
If the unit to be linked is linked with a coupling function and redundancy with system packet 3.02, a bus traffic disturbance can occur, and the linking unit can be excluded from the bus traffic. Owing to the full send FIFO, this unit signals a partial disturbance on the affected bus (error status: ‘FIFO disturbance ABx’).
The underlying cause is:
- Error in the bus RUPI up to Version < 1.03
The cause of the incorrect entries in the subscriber lists is the incorrect transcription of the sender of a link message by the bus RUPI (Remote Universal Peripheral Interface). The mounting position code (EPC) of the redundant unit to be linked is evaluated as the mounting position code of the sender. As a result, no entry is made in the redundant unit to be linked as this is its own mounting position code.
After linking, the system triggers the RESET of the RUPIs. As a result, the subscriber list with the missing subscriber is transferred to the RUPI in the redundant unit. On the bus the missing subscriber is then not recognized and excluded from the bus traffic. The RUPI of this subscriber cannot send any further telegrams to the bus, with the result that after a certain period, the FIFO overflows and the signal for a partial disturbance is sent.