Special relays/special registers capable of high-speed transfers
with the HCMOV/DHCMOV instruction
The table below shows the devices that can read and write the latest value with the HCMOV/DHCMOV instruction from
special relays and special registers related to the high-speed counters. When special relays and special registers are
specified for (s) and (d) of instructions other than the HCMOV/DHCMOV instruction, the operation is the same as one
compatible with the MOV/DMOV instruction.
• Transfer is not possible between an SM supporting high-speed transfer and an SD supporting high-speed transfer.
• When the device supporting high-speed transfer is set as the transfer source (s) by the DHCMOV instruction while the high-
speed input/output function is stopped, the previous value before stop is read out. However, if the function is not executed
even once, the initial value is read out.
Special relays for individual channels
: High-speed transfer capable (special relay is immediately updated)
: Normal transfer capable (special relay is updated in END processing)
: Transfer not possible (read-only)
Special relay Function
High-speed counter operating
High-speed counter pulse density/rotational speed being measured
High-speed counter overflow
High-speed counter underflow
High-speed counter count direction monitor
High-speed counter (1-phase 1-input S/W) count direction switch
High-speed counter preset input logic
High-speed counter preset input comparison
High-speed counter enable input logic
High-speed counter ring length setting
*1 In a program with interruption priority 1, the HCMOV/DHCMOV instruction specified with a device for the high-speed pulse input/output
module cannot be executed.
Compatible with HCMOV/
Compatible with MOV/
24 HIGH-SPEED INPUT/OUTPUT FUNCTION
24.1 High-speed Counter Function