Siemens SIMATIC CP 340 - Page 112

Communication using function blocks
6.3 Using the function blocks for connecting to a communications processor
PtP coupling and configuration of CP 340
112 Manual, 04/2011, A5E00369892-03
Time Sequence Chart for FB 2 P_RCV
The figure below illustrates the behavior of the parameters NDR, LEN and ERROR,
depending on how the EN_R and R inputs are wired.
1'5
(1B5
5
(5525
(QDEOHUHFHLYH 7HUPLQDWLRQZLWKRXWHUURU 5HFHLYLQJ 7HUPLQDWLRQZLWKHUURU 5HFHLYLQJLVVZLWFKHGRII 1RWUHFHLYLQJ 5(6(7 7HUPLQDWLRQZLWKRXWHUURU 5HFHLYLQJ 7HUPLQDWLRQZLWKHUURU
/(1
OHQJWK
Figure 6-2 Time Sequence Chart FB_2_P_RCV
Note
The EN_R input must be set statically to "1". The EN_R parameter must be supplied with
logic operation result "1" throughout the entire receive request.