pH 170/
pH 296
Configuration
134
Frequency regulator (PF)
In frequency regulation - within a
preselected proportional band - the output
relay is clocked where the
clock frequency is higher or lower
depending on the deviation from the limit.
•
In larger deviations of the measured
value from the limit, the switching rate
is higher.
•
If the value is close to the limit, the
relay is actuated less often.
While the frequency varies depending on
the deviation from the limit, the pulse
duration
t
ON (0.3 sec.) remains constant.
Pulse frequency regulators are used for,
e.g. the control of magnetic dosing
pumps.
Outside the proportional band set up, Xp,
the maximum frequency is output and,
thus, the maximum possible performance
of the pump achieved.
The maximum possible frequency is
entered via the software.
Setting parameter:
Setting range:
50 to 120 pulses/min
Proportional band, Xp:
Set in steps of 0.1 pH over the whole measuring range
Basic setting:
70 pulses/min, proportional band of 1 pH
Relay
ON
OFF
Time[s]
t
ON
T
Pulse frequency =
Number of pulses
S
