Mitsubishi MELSEC-A Series Reference Manual page 23

1. OVERVIEW
Table 1.3 Differences between QCPU and A/QnACPU local stations (Continued)
Item
LRDP/LWTP instruction
receive processing
Access from peripheral to
host station
Access from peripheral to
other stations *1
Network diagnostics of GX
Developer
Forward loop test
Reverse loop test
Replacement for special
relay (for link)
QCPU local station
Handles the received instruction with the
sequence program.
If the LRDP/LWTP instruction is received
when the CPU module is in STOP status,
sends an error responce to the master
station (4: LRDP/LWTP inexecutable on
the station).
The following are not available.
• Buffer memory batch monitor/test
• Network diagnostics of GX Developer
Unable to access other stations.
• Master station QCPU local station
• QCPU local station Master station
Unable to use the network diagnostics of
GX Developer.
The data link status or fault location can be
checked by refreshing the special relay (for
link) and special register (for link) of the
local module into CPU module devices.
Place the QCPU local station into RUN
status (Y10 = ON) to conduct the test.
If the test is conducted in STOP status
(Y10 = OFF), the master station treats the
QCPU local station as a faulty station
(relevant bit in D9228 to D9231 is turned
ON).
However, the test is normally conducted.
LRDP instruction receive request (Buffer
)
memory address: AC
H
LWTP instruction receive request (Buffer
memory address: AE )
H
Hardware failure (RUN LED: OFF)
Link status (X0)
*1 When replacing with a QCPU local station, the following alternative solution can be applied to
GOT communications.
Table 1.4 Alternative solution for GOT communications
Before replacement
GOT is connected to master station to
access A/QnACPU local station.
GOT is connected to A/QnACPU local
station to access master station.
Description
The system handles the received instruction.
(The program for receiving LRDP/LWTP instruction is not
required.)
Not particularly restricted.
• The master station can access A/QnACPU local stations.
• A/QnACPU local stations can access the master station.
Can use the network diagnostics of GX Developer.
Place the A/QnACPU local station into STOP status to
conduct the test.
LRDP instruction completion (M9204)
LWTP instruction completion (M9205)
Link card failure (M9211)
Link status (M9240)
• Send/receive the link data of the devices that are used for
access from the GOT.
Change the setting so that the GOT can access the devices
refreshed on the host station.
• If the number of link points is insufficient, install another
local module to the QA1S6 B extension base unit where
the QCPU local station is mounted.
1 - 12
A/QnACPU local station
Alternative solution