
B–63503EN/02
9. CONNECTION TO FANUC I/O Link
167
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
when they are off (max. 40 mA).
DOCOM
CE56(A24, B24, A25, B25)
CE57(A24, B24, A25, B25)
+24V 0V
+24 stabilized
power supply
Relay
DV
DV
The DO driver of the I/O module is capable of detecting an overcurrent
and measuring its own temperature. If an accident, such as the connecting
of 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 and 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 I/O module continue operating. The DI
address (Xm+15) identifies the DO driver which has detected the alarm.
The following table shows the correspondence between the DI address
(Xm+15) bits and the DO addresses. Bit value “1” indicates that the
corresponding DO driver has detected an alarm. The contents of the
Xm+15 area can be checked by using the DGN screen of the CNC or by
performing alarm processing for the area in advance by using Ladder.
This helps alarm detection and recovery.
Parallel DO (output
signal) connection
DO (output signal) alarm
detection