LED’s show the operational status of the instrument or setup program
currently available. Pushing the encoder prepares for performing configu-
rations or calibrations. Rotating the encoder clockwise and pushing again
enters the configuration menu to set up the instrument. Rotating the
encoder anticlockwise and pushing enters the calibration menu. You scroll
through menus with the encoder knob and once a menu is selected values
are increased or decreased by rotating the encoder knob clock- or
anti-clockwise. The desired value is selected and saved with pushing the
encoder until the “SAVE” LED flashes two times.
(See configuration)
The large LCD display shows either signal input, configuration or
calibration values such as set point or high/low alarm as selected by an
operator.
F
The rotary encoder only becomes active if invoked through the instrument
configuration program. This feature avoids setpoint or calibration values
being changed inadvertently.
Three modes of set point control are possible with Relay1:
Normal dosing
(nor)
This is the normal dosing mode with simple on/off operation of the
output relay. Up or down dosing is possible with normal dosing.
Normal Proportional dosing
(no.P)
The relay output starts to pulse with a shortening of the ON cycle and
a lengthening of the OFF cycle as the pH / mV moves toward the setpoint.
The behaviour of the pulse mode can be modified by setting a “gradient”
from 10 to 100.
(See Fig. 6)
Minimum default pulse ON time when reaching
the set point is 2 seconds. This can be changed from 1 to 9 seconds to
suit all applications. These configurations only becomes available if
no.P
is selected. Up or down dosing is possible with normal proportional dosing.
Adaptive proportional dosing.
(Ad.P)
The relay output of the PMH-2 instrument is controlled through a
complex algorithm that continuously monitors the difference between
actual pH / mV and set point. The output starts to pulse and varies the
PAGE 6
PMH-2 Instruction manual
