Typical output blocks
Output blocks form the connections between the program and the connection terminals on the controllers. They control the plant components connected to the controller, including air dampers, fans, or heating coils.
The following output blocks are typically used:
- Output block CMD_B for binary controlled plant components
- Output block CMD_A for analog controlled plant components
- Output block CMD_M for multistate controlled plant components
① Normal mode
② General exception mode
③ Local exception mode
④ Output blocks
Control of output blocks is based on the present operating mode group normal mode or exception mode.
The switch-on sequence and switch-off sequence of the output blocks can be defined via locking.
In normal mode, the function block CMDSEQ_B determines, which output block is switched as well as its switch-on and switch-off sequence based on the received plant operating mode.
The signal priority is set on the output blocks (in normal mode, typically priority 15 = 'Automatic mode'). The output blocks switch the connected plant components.
As soon as the requested plant operating mode 1...16 changes on the input of function block CMDSEQ_B, the plant components are switched off as per the switch-off sequence and the newly required plant components are switched on as per the switch-on sequence.
In general exception mode, the output blocks are enabled directly by the input blocks, where applicable via function blocks in between.
For an enabled exception mode, the normal mode is ended immediately via CMDSEQ_B.
The signal priority is set on the output blocks (typically priority 5). The output blocks switch the connected plant components.
The switch-on sequence and switch-off sequence of the output blocks can be defined via locking.
As soon as the exception mode no longer applies, the normal mode is once again active and switches the plant components required for the present operating mode via CMDSEQ_B.
An active, local exception mode can act either on specific output blocks or can also be returned to the general exception mode.
Where only a specific output block is affected, normal mode continues to operate via function block CMDSEQ_B.
Where returned to the general exception mode, the rapid shutdown of the connected plant components and output blocks are controlled directly as per the priorities of the local and the general exception mode.