Chapter 6 Applied Instructions the extension module, the filtering time unit is ms. This instruction is for refreshing the current filtering time; filtering time set in HWCONFIG will NOT be affected. But when the value of Filter in the instruction exceeds the setting range in HWCONFIG, PLC treats the value of Filter as the maximum or the minimum value set in HWCONFIG. 5. When power-on, the filtering time of the CPU and the extension module is refreshed according to the filtering time set in HWCONFIG. 6. The REFF instruction refreshes the filtering time only at its first execution. 6_ 6-177