Function Mechanism Of The User-Defined Time Of Day Input - Siemens LOGO! 8 Manual

3 Mode of Operation

3.2 Function mechanism of the user-defined time of day input

Note Please note that for the time of day value "00:00" h, the analog value "2400"
must be entered. Entering the value "0000" as analog value prompts a warning
message stating that the time format is wrong.
3.2 Function mechanism of the user-defined time of day
input
The time base for setting the switch-on time for the street lights is implemented
with a weekly timer and a wiping relay.
The analog value written to the LOGO! program as time of day input is further
processed as pulse width parameter (TH) via the wiping relay.
For switch-on time "1130", for example, the calculated pulse duration (TH) is 690
minutes. Converting the 690 minutes yields 11 hours and 30 minutes.
Figure 3-2
Each day at 00:00 h, the weekly timer sends a pulse for one minute. As soon as
the wiping relay detects this pulse at the "Trg" input, the pulse width (TH) is
counted down in minutes (690 minutes in this example).
After the pulse width (TH) of the wiping relay has elapsed, the street lights are
switched on.
Note The pulse of the weekly timer for counting the pulse width is sent at 00:00 h
every day by the wiping relay. When entering a user-defined switch-on time as
an analog value, this value will be counted down as pulse width (TH) by the
wiping relay on the following day. The inserted switch-on time for the street lights
therefore applies to the following day.
LOGO! Set 1
Entry ID: 109063024, V1.0, 07/2015
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