Program
6.5 Technical specifications of the blocks
Counter module FM 450-1
52 Manual, 02/2014, A5E03648739-02
Description of the symbols
The tables lists the symbols used in the example. You specify your own symbol assignments
in the S7 symbol table.
Table 6- 1 Symbols in the user program
Data block for FC°CNT_CTRL
Counter value specified in DB 1
Initiation bit generated to meet technological requirements
Accept counter value directly
Acknowledge operator error
Load counter value in preparation
Reset synchronization status bit
Reset zero crossing, overflow and underflow status bit
Operator error information in DB 1
Description of the sequence
Prerequisite:
The value to be transferred must have been entered in the DB°1.
The load value is transferred and started:
When the FC is called, the load value of a channel is transferred to the FM 450-1. Calling the
FC°CNT_CTRL selects either the L_DIRECT parameter or the L_PREPAR parameter. The
L_DIRECT selection bit specifies that the load value will be loaded directly onto the counter
(L_DIRECT=1). The L_PREPAR selection bit specifies that the load value is to be stored in
the load register (L_PREPAR=1). The load value in the load register is then loaded onto the
counter when the counter is next set. L_PREPAR=1 prepares a new counter value. Load
value transfer lasts a minimum of 3 FC calls.
The FC must be called until it has reset the selected initiation bit (L_DIRECT or L_PREPAR).
While the job is in progress the I/O parameter remains set. The FC°CNT_CTRL does not
output an error message regarding data exchange with the FM.
If the FC CNT_CTRL resets the parameter you had set, the FM 450-1 has accepted the load
value. The read-back load value stored in the DB°1 is updated by the FC°CNT_CTRL.
You must generate the "initiation" bit to comply with your technological requirement. This bit
may be set at "1" for one cycle only. Please note, that the FC must be called until the I/O
parameter of the FC CNT_CTRL is reset.
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