24.2
FX3-compatible high-speed counter function
FX3-compatible high-speed counter function is explained below.
FX3-compatible high-speed counter function overview
The FX3 compatible high-speed counter can assign the input terminals compatible with FX3 and use the device equivalent to
C235 to C255 of FX3 as LC35 to LC55 (high-speed counter). The FX3-compatible high-speed counter function is not
supported in high-speed pulse input/output modules.
If the FX3 compatible high-speed counter is used, it is necessary to use the parameter to set the FX3 compatible high-speed
counter to be valid.
This section describes the device (LC35 to LC55) of the FX3 compatible high-speed counter as an LC device.
The FX3 compatible high-speed counter is convenient if it is used when a replacement is made from FX3 or
for a similar occasion. If a high-speed counter is newly used, use the high-speed counter function of FX5.
(Page 184 High-speed Counter Function)
How to start/stop the high-speed counter using the LC device
The method of starting/stopping the counting of the high-speed counter using the LC device is as follows.
Programs example
In the case of a program shown below, the counting starts when M0 turns ON, and the counting stops when M0 turns OFF.
When the counter increases from -6 or less to -5 or higher during an execution of the UDCNTF instruction, the counter contact
turns ON, and the counter contact turns OFF when the counter decreases from -5 or higher to -6 or lower. ON/OFF of M1
switches the counting direction. To count from 0, turn ON M2 to reset LC35.
M0
UDCNTF
LC35
LC35
M1
M2
RST
• The current value of LC35 is updated when the UDCNTF instruction is executed.
• When LC35 is set to (s) of the DHCMOV instruction, the newest value can be read out.
• When a high-speed comparison instruction (DHSCS instruction, DHSCR instruction, DHSZ instruction), a
high-speed comparison table, or a multi-point output high-speed comparison table are used, an accurate
comparison and matched output processing can be executed.
The set value (positive or negative) can be specified by a constant (K) or the contents of data registers (D). When data
registers are used, 32-bit data composed of two consecutive devices are treated as set values. If D0 is specified, the pair of
D1 and D0 are the setting value of 32 bits.
K-5
Setting value (constant)
Indirect specification is possible
Y1
SM4580
LC35
24 HIGH-SPEED INPUT/OUTPUT FUNCTION
24.2 FX3-compatible high-speed counter function
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