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The controller will dose reductants to lower the ORP value to the de-
sired value. Since it is 25/100 = 25% away from the ideal setting,
it will keep activated the
dosing relay for 25% of the
time over the predetermined
60 seconds.
The terminals are hence
activated for 15 seconds and
off for 45 seconds until the
next cycle.
• If the setting is left at 0 pH or 0 mV, the controller will operate
with no proportional dosage, with an hysteresis of approximately
0.1 pH or 7 mV.
• Do not set the time cycle to zero. This will cause the relay to chatter
and can be detrimental to system and pumps.
Notes:
This means shortening the dosage time if the chemicals have reacted
quickly or lengthening it if the
measured pH continues to drift
from the ideal setpoint as can
be seen from the graphs.
ORP proportional control, example
Setpoint = 725 mV
Reading = 700 mV
Setpoint - Reading = 25 mV
Proportional settings = mV set to 100 and time cycle to 60 seconds.
