Every time the input energy flow transitions from closed to open, the Count Up (CTU) instruction counts up from the current value. When the current value (CVxxx) is greater than or equal to the preset value (SV), the counter bit (Cxxx) is turned on. When reaching the maximum value (32767 or 2147483647), the counter stops counting. Performing a reset operation can reset the counter, that is, the counter bit (Cxxx) is set to 0, and the current value of the counter (CVxxx) is set to 0.

Counter range: CVxxx=CV0 to CV255; Cxxx=C0 to C255.

Counter Type	Counter Bit Number	Maximum Value	Counter Number
CTU	16 bits	32767	C0-C199
CTU	32-bit	2147483647	C200 – C234
CTU	32-bit (high-speed)	2147483647	C235-C255

Note: Since each counter has a current value, do not set the same counter number to more than one counter (up and down counters with the same number access the same current value).

Input/Output	Data Type	operand	Description
CV	16 bit integer	CV	Counter
SV	16 bit integer	D/CV/TV/AI/AO/K/H/V/Z/FD, bit composite word (X/Y/M/C/T/S), local variable (LW)	preset value

Command table:

NETWORK 000

LD X000

CTU CV0 D0 // The counter starts counting upwards from the current value CV0, and the set value (SV) is D0

NETWORK 001

LD C0

OUT Y000

图1 CTU