pH 170/
pH 296
Configuration
132
Pulse regulator (PI)
In impulse regulation, the output relay -
within a preselected proportional band -
is clocked and the switch contact is
closed for a longer or shorter time
according to the deviation from the limit.
•
In larger deviations of the measured
value from the limit, the contact is
closed longer and the pause is short.
•
If the value is close to the limit, the
contact is closed only briefly and the
pause is correspondingly longer.
The total time (switch-on and switch-off
time) is designated as the switching
period, T.
While the switching times vary
depending on the control deviation, the
time intervall, T, remains constant (see
adjacent figure).
Pulse duration regulators are used for,
e.g. the control of valves.
Within the set up proportional band, Xp,
the relative duration of operation of the
relay lies between 10 and 90%.
Setting parameter:
Setting range T:
5 to 100 sec. (interval)
Proportional band, Xp:
Set in steps of 0.1 pH over the whole measuring range.
Basic setting:
10 sec, proportional band of 1 pH
Relay
ON
OFF
Time[s]
t
OFF
t
ON
T
Relative switching duration= t
. 100 %
T
ON
