Special register details
This section describes details about the special registers used with the high-speed counters.
High-speed counter current value
These devices store the current values of the high-speed counters.
The device numbers corresponding to each channel are as follows.
High-speed pulse input/output module
These devices stores the current values of the high-speed counters.
These are signed 32-bit ring counters. (Upper limit value+1 changes to → lower limit value, lower limit value-1 changes to →
upper limit value.)
When the ring length is not set, lower limit value: -2147483648, upper limit value: 2147483647.
When the ring length is set, lower limit value: 0, upper limit value: ring length-1.
• To rewrite the current value, use the HCMOV/DHCMOV instruction and transfer the desired value. However,
this is the upper limit when set to a value that exceeds the upper limit value, and this is the lower limit value
when set to a value that is less than the lower limit value.
• If the current value falls outside the ring length range when the ring length is set, the upper and lower limit
values of the ring length are ignored and the current value is used.
• The current value is retained even when the power is OFF.
The current value of the high-speed counter is updated in END processing or when the HCMOV/DHCMOV instruction is
executed. Further, when the FX3 compatible high-speed counter function is valid, the value is updated also when UDCNTF
instruction is executed.
The timing when the device is cleared is as follows.
• Cleared by the HCMOV/DHCMOV instruction
• When the RST LC instruction executes ON (only when the FX3 compatible high-speed counter function is valid and the
applicable LC device is used)
• Power ON, reset, RUN→STOP (only when the FX3 compatible high-speed counter function is valid and the applicable LC
device is used)
24 HIGH-SPEED INPUT/OUTPUT FUNCTION
24.1 High-speed Counter Function