
B-63943EN/02 8.CONNECTION TO FANUC I/O Link
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NOTE
When the DO signal is in the ON state in the
sequence, the ON or OFF state of the DOCOM pin
determines the state of the signal, as indicated by
the dotted lines in the above figure. Do not turn
off the +24 V supply, provided by the CPD1 to the
I/O module, during the operation. Turning off the
+24 V supply would cause a CNC communication
alarm. When turning on the power, the +24 V
supply to the I/O module must be turned on before
or at the same time as the power supply to the
CNC. When turning off the power, the +24 V
supply to the I/O module must be turned off after or
at the same time as the power supply to the CNC.
Parallel DO (output signal) connection
The DO load current can be doubled by connecting two DO points in
parallel and turning them on and off simultaneously in sequence, as
shown in the figure below. The maximum load current per DI point
is 200 mA. Connecting two DO points in parallel and turning them
on at the same time produces a current of 400 mA. Note that,
however, when two DO points are connected in parallel, the leakage
current also doubles while they are off (max. 40 µA).
DOCOM
CE53(A25), (B25)
CE54(B24), (A25), (B25)
DV
+24 stabilized
power supply
+24V 0V
Relay
DV
DO (output signal) alarm detection
The DO driver of the I/O module is capable of detecting an
overcurrent and measuring its own temperature. If an accident, such
as connecting the cable to ground, causes an abnormal increase in the
load current or in the driver temperature, a protection circuit, which is
provided for each DO driver (1 byte), is activated which keeps the DO
signal for the relevant 1 byte in the OFF state until the cause of the
problem is eliminated. Even if this occurs, the CNC and the I/O