Mitsubishi Electric Melsec QJ71LP21 Reference Manual page 82

3 SPECIFICATIONS
Item
Checks hardware including the send/receive circuits and the
Self-loopback test cables of the transmission system of an individual network
module.
Checks hardware including the send/receive circuits of the
Internal self-loopback test
transmission system of an individual network module.
Hardware test Checks hardware inside the network module.
Station-to-station test Checks a line between two stations.
Forward loop/reverse Checks the wiring status of the forward and reverse loops in
loop test the status in which all the stations are connected.
Item
Loop test Checks the line status.
Checks for duplicate control stations and
Setup confirmation test
station numbers.
Checks the order of stations connected
Station order check test in the directions of the forward and
reverse loop.
Checks whether or not the transient
transmission can be performed normally.
Communication test
It also checks the routing parameter
settings.
1: The setup confirmation test cannot be executed in the twisted bus system.
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(9) Diagnostic function
The diagnostic function is used to check the network's line status and the module
setting status.
The diagnostic function consists mainly of following two types of tests:
• Offline tests
• Online tests
POINT
Execute the online tests when the network module is communicating (T.PASS LED
is on). An error occurs if any of the online tests is executed from a station that has
been disconnected from the data link.
1) Offline tests
The network module's hardware and the data link cable wiring can be
checked at the system startup by setting the network module or GX
Developer to the test mode.
Description
2) Online tests
The status of a line and other items can be easily checked with GX
Developer.
If an error occurs while the system is in operation, the diagnostics
listed below can be executed while remaining in the online status.
Description
Optical loop
system
Optical loop Coaxial/twisted
system bus system
1
MELSEC-Q
Coaxial/twisted Reference
bus system section
Section 4.5.1
Section 4.5.2
Section 4.5.3
Section 4.7.1
Section 4.7.2
Data link status
Reference
(cyclic transmission or
section
transient transmission)
Pause Section 4.8.1
Pause Section 4.8.2
Pause Section 4.8.3
Continue Section 4.8.4
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