Programming Example for Standard Function Blocks
9.6 Activation, Startup Program and Cyclic Program
Point-to-point connection CP 440 Installation and Parameter Assignment
134
Manual, 09/2007, A5E00057742-03
The "Enable Receive Data" program section:
Before data can be received, the receive enable (RECV_EN_R) at block RECV_440 must be
set to "1".
"RECV_NDR=1" program section:
When RECV_NDR is set, new data has been received and the RECV_COUNTER_OK
receive counter is incremented.
"RECV_ERROR=1" program section:
If execution is unsuccessful (i.e. if the error bit is set at the parameter output of RECV_440),
the RECV_COUNTER_ERR error counter is incremented. The RECV_STATUS is copied,
because it is overwritten with 0 in the next run and it will thus not be possible to read it out.
All relevant values can be observed for test purposes in the variable table.
9.6.2
"CP440 1 CYC" Program Example
This example is set up identically to the example "CP440 SEND RECV". However, the FC 21
has been changed to allow a SEND job to be processed cyclically.
Description of FC 21 (SEND)
The procedure for processing a SEND job cyclically is as follows:
●
At each block call, SEND_440 is run through with SEND_REQ=0. If neither SEND_DONE
nor SEND_ERROR are present, the block is terminated.
●
If SEND_DONE is present, SEND_440 is run through again with SEND_REQ=1.
●
If SEND_ERROR is present, SEND_440 is run through with SEND_REQ=0 and then with
SEND_REQ=1.
To ensure that SEND_440 can be run through with SEND_REQ=1 in the very first pass, the
SEND_STARTUP_ENDED bit is also evaluated in the program section "Check if
SEND_DONE or SEND_ERROR or not first Cycle". This bit is at 0 during the first pass and is
then fixed at 1.
See also
"CP440 SEND RECV" Program Example (Page 133)
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