S3 / S4 Proportional
In Proportional mode the relay output starts to pulse on and off once
the electrode-input moves toward the setpoint. The difference of input
versus setpoint is controlled by the amount of “gradient” set in the
configuration program. The lowest setting of 10 starts the output relay
pulsing if 240 mV below/above setpoint in mV mode, or 3.0pH be-
low/above setpoint in pH mode. The on/off ratio gradually reduces until
the relay switches off at setpoint.
Setting the gradient to the maximum of 100 starts the output relay
pulsing when 10 mV or less than 0.5pH below/above setpoint giving a
very steep gradient. The on/off ratio reduces very rapidly. Up or down
mode is possible with normal proportional dosing. Look up Fig.6 for
‘gradient’ versus pulse output. Proportional dosing can be used with the
timed relay option to only operate at programmed times or days.
S3 / S4 Temperature
A HOFMANN TP-150 temperature sensor must be connected to use
temperature control with S3 and S4. Both can be set for above or below
temperature operation with a setpoint range from 0 to 100
o
C and an
adjustable deadband of 0.2 to 10.0
o
C. The ‘TIMED RELAY’ option for S3
and S4 can also be used for temperature control.
.1/ & The effect of gradient on proportional dosing
DPH-64 Instruction manual
PAGE 19
