YSI DIQ/S 182 XT-4 System 182 XT-4 - Manual (Page 103)

System 182 XT-4 Outputs
6 - 11 ba76026e01 01/2012
Frequency output Switching frequency output is used, e.g. for controlling dosing pumps.
In contrast to the pulse-width output, the pulse width is not modulated
with the frequency output but the switching frequency of the output
signal. Depending on the position of the measured value in the
proportional range, the relay is switched more often or less often.
Fig. 6-5 Relay output of frequency output
While the selected switching duration (t
on
= 0.3 s) always remains
constant, the switching frequency at which the relay switches changes
depending on the measured value.
 If the measured value is at the end of the proportional range (End
value), the switching frequency is higher.
 If the measured value is at the beginning of the proportional range
(Start value), the switching frequency is low.
Time [s]
t = 0.3 s
On
Relay
Off
On
T