Mitsubishi Q2ACPU, User Manual

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10.
10 - 23
OTHER FUNCTIONS
10.8 Reading Module Access Time Intervals
The QnACPU can monitor the access interval time (The time between one access
reception and the next access reception) for intelligent special function modules, network
modules, data link modules, or GPP function. This enables to grasp the frequency of
accesses to the CPU module from external sources.
The operation for reading the module access interval time involves the following special
relay and special registers.
(1) Special relay
(2) Special register
Program example:
Program for reading the module access interval time of the special function module at
X/Y160.
Number Name Description
SM551
Read module service
interval
When this relay turns from OFF to ON, the module access interval time for the
special function module specified in special register SD550 is read into special
registers SD551 to SD552.
ON : Read
OFF : Ignored
Number Name Description
SD550
Service interval
measurement module
Set the I/O number of the module whose access interval time is to be measured.
Set the I/O number of the peripheral device connected to the RS-422 interface of
the CPU module to FFFF
H
.
Also set the I/O number of the upper 2 digits in the 3-digit representation.
SD551 to SD552 Service interval time
When SM551 is turned ON, it stores the interval time for access from the module
specified at SD550.
SD551: 1ms units (Range: 0 to 65535)
SD552: 1 s units (Range: 0 to 900, stored every 100 s)
POINT
To read the access interval time for access from GPP function at another station in
the network, set the I/O number of the network module.
Example: When the module access interval time is 123.4ms:
SD551=123, SD552=400