Rockwell Automation 1771-KA2 Communication Adapter Module - Manual (Page 115)

Start–up and Troubleshooting
Chapter 9
9-13
Overall Approach
In start-up testing, it is best to limit the number of things happening at one
time. By carefully limiting the scope of start-up testing to a small number
of variables, the source of a problem is more readily detected.
Paired Testing
In the early stages of Data Highway testing, limit the size of the group of
stations being tested. Initially, start-up testing is done with only 2 stations
communicating at a time; all other stations are OFF. Then, after each
station has been tested in this manner the testing of more than 2 stations at
a time can begin. Finally, after comprehensive testing of all stations,
station processors can begin normal operation.
To begin, one station is selected as a starting point. For the purpose of
this description, this station is labeled A. Any station to which station A
sends a command can then be selected as station B. The first testing is
then carried out between stations A and B, with all other station interface
modules disconnected. Each command from A to B is tested and
monitored to verify proper operation. Then station B is checked for any
commands that it received from station A and for any commands that it
sends to station A.
Once testing between these two stations has been completed, station B is
disconnected and another station, C, is selected, again based on its being
addressed by a command from station A. Since station A has already
been tested for several functions, problems with station C can be more
readily located and corrected.
Paired testing continues in this manner until all commands programmed at
station A have been tested. Then, commands from station B are tested
with other stations. This procedure continues, with pairs of stations being
tested each time until all commands sent on the Data Highway have been
checked in this manner.
By following this procedure, you test each command for proper execution
by the station interface modules at each station. This testing also checks
the support programming done at each station to initiate and monitor
commands, including REMOTE/LOCAL FAULT monitoring.
The procedures of sections titled “Testing the Sending Station” and
“Testing the Receiving Station” are used for paired testing of stations. For
a station sending a command, carry out the procedures of section titled
“Testing the Sending Station.” At the receiving station, carry out the
procedures of section titled “Start-up Procedures.”