User`s manual

2-4
Precautions for Use
2
(19) Special I/O modules
If a preset scanning time is too short ( less than 2 ms), the special I/O module such as JW-21SU may
not function normally.
To avoid this malfunction, set a longer scanning time using a constant scanning (set 3 ms or more on
the system memory #226) or other functions.
(20) Insulation resistance and dielectric strength tests of the power supply module
When testing insulation resistance or dielectric strength of the JW-21PU/31PU power supply
modules, be sure to remove the short bar connected between the SHORT terminal and the GND
terminal. If a test is carried out without removing the short bar, internal elements of the module may
be damaged.