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MELSEC-Q
1 GENERAL SPECIFICATIONS AND PRECAUTIONS FOR USE
(5) Fuses installed to external terminals
It is recommended to install fuses to each external terminal. These fuses works to
prevent the external devices and the module from being burned when a short circuit
occurs in the load circuit of the QY22 or QY68A.
The following table lists the fuses whose operations have been checked and
ensured by Mitsubishi.
Module model QY22*
1
QY68A*
2
Fuse model 216 02.5 216 002 216 3.15 312 003
Rated current 2.5A 2A 3.15A 3A
Manufacturer Littelfuse, Inc
*1: Fuses that conform to Sheet 1 of IEC60127 are recommended.
*2: Fast blow fuses whose rated current is 3A are recommended.
(6) Precautions for using the transistor output module
(a) Action against reverse current
If a transistor output module is wired as shown below, reverse current flows in
an output element, causing a failure of the element.
When wiring a transistor output module, connect a diode as shown below.
• When connecting transistor output modules in parallel
Sink type Source type
• When incorporating an additional circuit parallel to a transistor output
module
OUT
COM
Sink type
Additional circuit
Source type
Diode
OUT
COM
Diode
Additional circuit