User Manual

LOGO! functions
4.4 Special functions list - SF
LOGO!
176 Manual, 06/2014, A5E33039675
4.4.16
Hours counter
Short description
A configured time is triggered with a signal at the monitoring input. The output is set when
this time has expired.
Symbol in LOGO!
Wiring
Description
Input R A positive edge (0 to 1 transition) at input R resets
output Q and sets a configured value MI at the
counter for the duration of the time-to-go (MN).
Input En En is the monitoring input. LOGO! scans the on-time
of this input.
Input Ral A positive edge at input Ral (Reset all) resets the
hours counter (OT) and the output, and sets the time-
to-go value (MN) to the maintenance interval MI:
• Output Q = 0
• Measured operating time OT = 0
• Time-to-go of the maintenance interval MN = MI.
Parameter
MI: Maintenance interval to be preset in units of hours
and minutes
Range of values:
0000 h to 9999 h, 0 m to 59 m
OT: the accumulated total operating time (you can
specify an offset in hours and minute)
Range of values:
00000 h to 99999 h, 0 m to 59 m
Q → 0 occurs depending on the following conditions:
• When "R" is selected:
Q = 1, if MN = 0;
Q = 0, if R = 1 or Ral = 1
• When "R+En" is selected:
Q = 1, if MN = 0;
Q = 0, if R = 1 or Ral = 1 or En = 0.
Output Q The output is set when the time-to-go MN = 0 (see
timing diagram).
The output is reset under the following conditions:
• When "Q→0:R+En", if
R = 1 or Ral = 1 or En = 0
• When "Q→0:R", if R = 1 or Ral = 1.
Note
MI, MN and OT are always retentive.