Toshiba GRT100 Series Instruction Manual page 52

3.1.4.2 IO2 Module
As shown in Figure 3.1.7, the IO2 module incorporates 3 photo-coupler circuits (BI14-BI16) for
binary input signals, 14 auxiliary relays (BO1-BO13 and FAIL) for binary output signals and
RS-485 transceivers.
The auxiliary relay FAIL has one normally closed contact, and operates when a relay failure or
abnormality in the DC circuit is detected. BO1 to BO13 each have one normally open contact.
The BO12 and BO13 are the high-speed operation type.
The RS-485 transceivers are used for the link with three kinds of communication protocols. In
case of single RS485 port (COM1) model, it can be applied to RSM system, IEC60870-5-103 or
Modbus communication by the setting. Incase of dual port (COM1 and COM2) model, COM1
port can be used for RSM system, IEC60870-5-103 or Modbus communication same as sigle
port model and COM2 port can be used for IEC60870-5-103 communication when COM1 is set
for RSM system. The external signal is insulated from the relay internal signal.
Photo-coupler
BI14
Binary
BI15
input
signals
BI16
Auxiliary relay
RS-485
COM1 Transceiver
RS-485
COM2
Transceiver
Figure 3.1.7 IO2 Module
 51 
BO1
BO2
Binary
output
signals
FAIL
Link with RSM system,
IEC60870-5-103 or
Modbus Communication
system
Link with
IEC60870-5-103
Communication
system
6 F 2 S 0 7 8 9