Siemens SIMATIC S7-1200 Manual page 110

Programming made easy
6.3 Powerful instructions make programming easy
Table 6- 17 CTU (count up) counter
LAD / FBD SCL
"ctu_db".CTU(
The timing diagram shows the operation of a CTU counter with an unsigned integer count
value (where PV = 3).
● If the value of parameter CV (current count value) is greater than or equal to the value of
parameter PV (preset count value), then the counter output parameter Q = 1.
● If the value of the reset parameter R changes from 0 to 1, then CV is reset to 0.
Table 6- 18 CTD (count down) counter
LAD / FBD SCL
"ctd_db".CTU(
The timing diagram shows the operation of a CTD counter with an unsigned integer count
value (where PV = 3).
● If the value of parameter CV (current count value) is equal to or less than 0, the counter
output parameter Q = 1.
● If the value of parameter LOAD changes from 0 to 1, the value at parameter PV (preset
value) is loaded to the counter as the new CV.
110
CU:=_bool_in,
R:=_bool_in,
PV:=_undef_in,
Q=>_bool_out,
CV=>_undef_out);
CD:=_bool_in,
LOAD:=_bool_in,
PV:=_undef_in,
Q=>_bool_out,
CV=>_undef_out);
Operation
Operation
Easy Book
Manual, 03/2014, A5E02486774-AF