Self-Loopback Test - Mitsubishi Electric QJ71MB91 User Manual

6
PRE-OPERATIONAL PROCEDURES AND SETTINGS

6.4.2 Self-loopback test

The self-loopback test checks the send/receive function of the QJ71MB91 and
communications with the programmable controller CPU.
(1) Self-loopback test procedure
STOP the programmable controller CPU.
Disconnect the communication cable connected to
the target device.
Connect a cable for self-loopback test.*1
Make the communication
speed/transmission settings. (Switch 2, 4)
Set it to the self-loopback test mode.
(Switch 1, 3 = 000D
Reset the programmable controller CPU.
Loopback test execution
(approx. 1 second per cycle)
ERR.LED OFF:
Normal operation
Signal name
Output for cable
disconnection
detection
Input for cable
disconnection
detection
Start
, 000E combination)
H H
ERR.LED ON: Error completion
Normal/Error
Monitor the buffer memory and check the
error.
End
Figure 6.6 Self-loopback test procedure
* 1 This is the cable wiring for self-loopback test.
QJ71MB91
CH1(RS - 232)
Pin No.
1
RD 2
SD 3
4
SG 5
6
7
8
9
Figure 6.7 Cable wirings for self-loopback test
Section 6.6
Section 6.6
QJ71MB91
CH2 (RS-422/485)
Signal name
SDA
SDB
RDA
RDB
SG
FG
FG
6.4 Unit Tests
6.4.2 Self-loopback test
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2
3
4
5
6
7
8
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