User`s manual

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MELSEC-Q

1 GENERAL SPECIFICATIONS OF INPUT AND OUTPUT MODULES AND

INSTRUCTIONS FOR SELECTING THEM

1. GENERAL SPECIFICATIONS OF INPUT AND OUTPUT MODULES AND

INSTRUCTIONS FOR SELECTING THEM

This chapter describes the general specifications of I/O modules and instructions for

selecting them.

1.1 General Specifications

Refer to the following manual for the general specifications of the I/O modules.

• QCPU User's Manual (Hardware Design/Maintenance and Inspection)

1.2 Selecting Instructions

(1) If an output module drives an inductive load, it must be switched ON for 1 second

or longer and switched OFF for 1 second or longer.

(2) If a counter or timer which has a DC-DC converter as a load is used with an output

module, using an average current to choose an output module can cause a fault

due to periodic rush currents when it is turned ON or during operation.

To reduce the influence of rush currents for use of the above load, connect a

resistor or an inductance to the load in series or use a module whose maximum

load current is larger.

Output

module

Resisto

Load Inductance

Output

module

Load

(3) Fuses installed in output modules cannot be replaced. They are designed to protect

external wiring if the module outputs are shorted.

Therefore, output modules may not be protected from a short circuit.

If an output module becomes faulty due to any cause other than a short circuit, its

fuse may not function.

(4) The number of signals, which can be turned ON simultaneously in an input module,

varies according to the input voltage and ambient temperature.

Refer to the corresponding input module specifications.