Siemens SIMATIC S7-400 CP 440, Установка и настройка параметров

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Commissioning the CP 440
Point-to-point connection CP 440 Installation and Parameter Assignment
Manual, 09/2007, A5E00057742-03
59
4. Check:
Always monitor the TXD send and RXD receive LEDs during the following operations
Example 1: The polarity of the line is definitely correct
–
The default settings (all options) vary
– Check the security word (e.g. CRC)
Example 2: The default settings are definitely correct
–
Reverse the connections (note: cross both pairs of lines in the RS422)
– Check the security word (e.g. CRC)
Example 3: Neither correct polarity nor correct default settings known
–
Reverse the connections (note: cross both pairs of lines in the RS422)
– If not OK, change the default settings (all options) with an appropriate communication
attempt
– If not OK, change the connections back, and change the default settings (all options)
– Check the security word (e.g. CRC)
When setting up again, don't forget to put back the terminating resistors you removed.
5. Additional tips:
–
If possible, connect an interface tester (possibly the V.24 → RS22/485 converter) to
the cable.
– Check the signal level using a measuring device (measure level to GND - pin 8).
– Some devices do not signal reception if data is being received but the CRC security
word is not correct.
– If necessary, replace the module to exclude the possibility of an electrical defect.
See also
Assigning parameters to the CP 440 (Page 65)
Parameters for the Communications Protocols (Page 67)
Managing the Parameter Data (Page 81)
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