wtw DIQ/S 181, Operating Manual, Page: 68 / 104

Outputs
DIQ/S 181
68
ba77083e01 02/2015
Monitoring limiting
values using one or two
relays
Fig. 6-1 Switching points for relays with the function of a limit indicator
A switching delay (t) can be set up for each relay for switching
processes. This is the time period for which a limiting value must be
exceeded before the relay switches. This prevents frequent switching if
the measured values are close to the limiting value.
6.3.3 Proportional output
In the case of proportional output, a relay switches cyclically on and off
in a defined measured value range (proportional range). At the same
time, the relay switches with a:

duration of operation that corresponds to the measured value
(pulse-width output, see page 70) or
1 Upper limit value (relay 1) exceeded
2 Selected switching delay t1 for relay 1 expired
Relay 1 switches
3 Hysteresis for upper limiting value (relay 1) undercut
4 Selected switching delay t1 for relay 1 expired
Relay 1 switches back
5 Lower limit value (relay 2) undercut
Selected switching delay t2 for relay 2 expired
Relay 2 switches
6 Hysteresis for lower limiting value (relay 2) exceeded
Selected switching delay t2 for relay 2 expired
Relay 2 switches back
Time
Measured
value
UL
LL
Hysteresis UL
Hysteresis LL
3
5
Relay 1
Relay 2
4
1
2
t1
t1
6
t2 t2