Specifications

IEC 1131-3 Instructions
10-17
S7-200 Programmable Controller System Manual
C79000-G7076-C233-01
Up/Down Counter
The Up/Down Counter function block counts up or down
from the preset value on the rising edges of the Count Up
(CU) or Count Down (CD) input. When the current value
(CV) is equal to preset, the output (QU) turns on. When
the current value (CV) is equal to zero, the output (QD)
turns on. The counter loads the current value (CV) with
the preset value (PV) when the load (LD) input is
enabled. Similarly, the counter resets and loads the
current value (CV) with zero when the reset (R) is
enabled. The counter stops counting when it reaches
preset or zero.
Note
Since there is one current value for each counter, do not assign the same number
to more than one counter. (Up Counters, Down Counters, and Up/Down Counters
access the same current value.)
Inputs/Outputs Operands Data Types
CD (FBD only) I, Q, M, SM, V ,S ,L, T, C, Power Flow BOOL
CU (FBD only) I, Q, M, SM, V, S, L, T, C, Power Flow BOOL
R (FBD only) I, Q, M, SM, V, S, L,T, C, Power Flow BOOL
LD (FBD only) I, Q, M, SM, V, S, L, T, C, Power Flow BOOL
PV (LAD & FBD) VW, IW, QW, MW, SMW, LW, SW, AIW, AC, Constant, *VD,
*AC, *LD
INT
QU (LAD & FBD) I, Q, M, SM, V, S, L BOOL
QD (LAD & FBD) I, Q, M, SM, V, S, L BOOL
CV (LAD & FBD) VW, T, C, IW, QW, MW, SW, LW, AC, *VD, *AC, *LD INT
xxx C0 through C255 CTUD
L
A
D
F
B
D
CTUD
CD
CU
R
LD
PV
QU
CV
QD
xxx
222 224
333
221