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25 HIGH-SPEED INPUT/OUTPUT FUNCTION
25.1 High-speed Counter Function
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.
■Corresponding devices
The device numbers corresponding to each channel are as follows.
■Description
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.
• When the FX3 compatible high-speed counter function is valid, the same value as one in the LC device
(LC35 to LC55) used as the high-speed counter is stored. When the current value is rewritten, the value in
the device is also changed, as well as the other way around.
■Update timing
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.
■Clear timing
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, RUNSTOP (only when the FX3 compatible high-speed counter function is valid and the applicable LC
device is used)
CPU module
CH1 CH2 CH3 CH4 CH5 CH6 CH7 CH8
SD4501,
SD4500
SD4531,
SD4530
SD4561,
SD4560
SD4591,
SD4590
SD4621,
SD4620
SD4651,
SD4650
SD4681,
SD4680
SD4711, SD4710
High-speed pulse input/output module
First module Second module Third module Fourth module
CH9 CH10 CH11 CH12 CH13 CH14 CH15 CH16
SD4741,
SD4740
SD4771,
SD4770
SD4801,
SD4800
SD4831,
SD4830
SD4861,
SD4860
SD4891,
SD4890
SD4921,
SD4920
SD4951,
SD4950
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