Chapter 3 Before Using I/O Module; Input Module - Mitsubishi Electric MELSEC-L Series User Manual

CHAPTER 3
3.1

Input Module

(1) Common precautions for all input modules
(a) Simultaneous on points
The number of simultaneous on points of input module depends on the input voltage and ambient temperature.
Refer to the derating chart of the input module specifications. (Page 29, CHAPTER 4)
(2) Precautions for using the DC input module
(a) Measures against back EMF
When an inductive load is connected, connect a diode in parallel with the load.
Use a diode that meets the following conditions.
• Reverse breakdown voltage is equal to or more than 10 times as large as the circuit voltage.
• Forward current is equal to or more than 2 times as large as the load current.
20
BEFORE USING I/O MODULE
IN
Inductive
load
Diode
COM
Positive common
IN
Inductive
load
Diode
COM
Negative common