Mitsubishi Electric MELSEC iQ-F Series - Precautions When Replacing Other Functions

4 Replacement from FX3U to FX5UJ
4.4 Conversion of the Projects
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4
Precautions when Replacing Other Functions
Precautions when Using the High-speed Counters
When the high-speed counters (C235 to C255) are used with the FX3U, they will not operate just by switching to the FX5UJ.
It is necessary to set the FX3 Series compatible high-speed counters and change the program by the parameter. For the
setting procedure, refer to the following.
Note that replacing high-speed counters C237, C240, C242, and C245 with FX3 Series compatible high-speed counters
LC37, LC40, LC42, and LC45 will decrease the maximum frequency.
If there is a problem with the maximum frequency, consider setting counters to unused LC devices or switching to the FX5U.
■Parameter Setting Procedure of the FX3 Series Compatible High-speed Counters
1. Select “Long Counter Specification” at the specification for High-speed counters.
[Parameter]  [FX5UJCPU]  [Module Parameter]  [High Speed I/O]  “Input Function”  “High Speed Counter” 
“Detailed Setting”  “Other”
2. Set the function of the high-speed counters used with the FX3U.
Select the input comparison enable/disable of the counter device and preset input compatible with the FX3 Series, and select
the control switch.