ON/OFF cycle as the input value approaches the set point value. The
ON/OFF cycle however is also adjusted from a ‘correction factor’, which
in turn is governed by the history of a previous dosing cycle. This makes
for a fully dynamic dosing control, which adapts for widely varying dosing
conditions.
(See Fig.7)
Dosing for an excessive period of time without a corresponding increase
in pH is recognized as a possible failure. The output begins to pulse,
preventing overdosing. The pulse output exhibits a very wide duty cycle.
The ON and OFF times are both dynamic, both varying from 1 to 60
seconds. Up or down dosing is possible with “Adaptive proportional
Dosing”. ! If using
AdP
the second relay must be configured as alarm !
F
The PMH-2 program prevents gross overdosing in the event of a process
upset or electrode failure. (Adaptive mode only)
FIG 2
LED's show different conditions.
PMH-2 Instruction manual
PAGE 7
