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7 I/O MODULES
MELSEC-ST
7.3 Precautions for Use
(1) Do not use I/O modules under pressure higher than the atmospheric pressure of
0m (0ft.) altitude. Doing so can cause a malfunction.
When using I/O modules under pressure, please consult your local representative.
7.3.1 Input module
(1) Input modules may import noise or similar as an input depending on the pulse width
of a signal.
This pulse width changes as shown below depending on the parameter-set
response time. The operating environment should be fully considered when making
the response time setting.
Response Time Setting
Minimum Value of Pulse Width
That May Be Imported
0.5ms 0.02ms
0.5ms 0.8ms
7.3.2 Output module
(1) When using an output module to drive an inductive load, make sure that the relay
inside the module is ON/OFF for 1 second or longer.
(2) When the counter/time that uses DC-DC converter as load is applied to an output
module, this causes the rush current to flow in a constant period while the device is
ON or operating. If an average current is selected in this condition, the module may
malfunction.
Therefore, when using above load, connect a resistor and an inductance to the load
in series or select a module that includes large maximum load current, in order to
reduce the influence of the rush current.
Output
module
Resistor
Load
Inductance
Output
module
Load
(3) A fuse for output module is unexchangeable, which is designed to prevent the
external wiring from burning out when the module output is shorted.
Therefore, the output module may not be protected.
The fuse may not operate if the output module is damaged due to other failure than
short circuit.
Summary of Contents for MELESEC-ST
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