User Guide

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In the first two cases the configuration of Setpoint (1 or 2)
determines the operating mode of the relay. Once enabled,
the control relay can be configured to control as a ON/OFF
or PID control of the acid/base dosage.
A High-hight Alarm is imposed for acid/base dosage time
when the relays are energized continuously. This parameter
can be set through setup procedure (CONTROL group, setup
item C.32). When the upper time boundary is reached, an
alarm is generated and device stays in alarm condition until
relay is de-energized.
If the “hold mode” is selected for the relay, then it is ener-
gized only when the meter is in hold mode. In this case there
is no time boundary for the ON state of the relay.
The option for relays 3 and 4 can be configured to opera-
tions in three modes:
1. simple cleaning;
2. advanced cleaning;
3. hold mode.
ON/OFF CONTROL MODE
Once a relay is enabled (set 1, set 2), the setpoint can be
configured to be activated as a high limit (“OOHI”) or as a
low limit (“OOLO”). In both cases the following values have
to be defined through setup:
• setpoint value (pH/mV; setup item C.11 or C.21);
• hysteresis for setpoint (pH/mV value; setup item C.12 or C.22).
A control device can be wired to the contact output.
Connect the device to the COM and NO
(Normally Open) or NC (Normally
Closed) terminals of the relay.
The ON relay state occurs when relay is energized (NO and
COM connected, NC and COM disconnected).
The OFF relay state occurs when relay is de-energized (NO
and COM disconnected, NC and COM connected).
The following graph shows relay state along with pH mea-
sured value (similar graph can be derived for mV control).
As shown below, when the measured pH exceeds the setpoint
threshold, the relay(s) is (are) energized, until the pH mea-