
4. FUNCTIONS
MELSEC-A
4-6
4.2.2
I/O signal detail description
(1)
Exchange start request signal (Y00), exchange start end signal (X00)
(a)
After the exchange start request signal (Y00) is turned on by the sequence program the
exchange start end signal (X00) is turned on when cyclic exchange starts.
(b)
The exchange start end signal (X00) turns off in either of the following cases.
•
When the exchange start request signal (Y00) is turned off
•
When the parameters are written from the configurator to the AJ71PB92D/A1SJ71PB92D
Exchange start request signal (Y00)
Exchange start end signal (X00)
Exchange start
request
Exchange start end
Maximum 200 ms
Exchange
(c)
An interlock is used for FROM/TO of the I/O data.
(d)
Before the exchange start request signal is turned on the output data initial value must be
written to the buffer memory.
(2)
Communication trouble detection signal (X01), communication trouble detection signal
reset (Y01)
(a)
The communication trouble detection signal (X01) is turned on when a communication
trouble occurs. At the same time the RSP ERR.'s LED turns on. At this time the error code
and detailed data are stored in the buffer memory communication trouble area.
(b)
The communication trouble detection signal (X01) is turned off when the communication
trouble detection signal reset signal (Y01) is turned on from the sequence program or when
communication failure is all resolved. At this time, the RSP ERR. LED is turned off.
(c)
The communication trouble detection signal reset (Y01) is turned off by the sequence
program after it has been confirmed that the communication trouble detection signal (X01)
has been turned off.
(d)
The following sequence is used.
Communication trouble detection signal reset (Y01)
Communication trouble detection signal (X01)
Trouble detection
Trouble detection reset
FROM
The error code is read from the buffer memory to the PLC CPU.
FROM/TO