Toshiba lf546 User Manual

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5.5 Digital I/O Connections 
Digital I/O terminals consist of contact output terminals (DO1 and DO2), voltage signal input   
terminal (DI), and signal common terminal (COM). Each terminal (DO1,  DO2 and DI) is isolated from 
internal circuits. Terminal (COM) is the signal common for the other three terminals (DO1, DO2 and DI). 
Functions can be assigned for each terminal with the LCD control keys. See Chapter 10, “Digital I/O 
Functions.”
 
To connect an electromagnetic relay or counter to the contact output terminal (DO1 or DO2), put a 
surge-absorbing diode into the input circuit of the relay or counter. See Figure 5.3 for an example of 
electromagnetic counter connection. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Figure 5.3    Electromagnetic Counter Connection Example 
 
Note 1:  Use a surge-absorbing diode of the rating: current rating 1A and voltage rating 200 V 
minimum
Note 2:  When a power supply-built-in electronic counter is used, the serge-absorbing diode is not 
required. 
Note2 
Solidstate relay 
Transistor open collector 
 
COM 
DI 
DO2 
DO1 
 
Resistor 
Note2 
Photo-coupler 
 
 
 
 
Note1 
Surge-absorbing diode 
Power supply 
24 V dc 
Electromagnetic counter 
Note2 
(Power supply-built-in electronic counter) 
Converter