User Guide

This is an important feature since with most meters the alarm

terminals close only when an abnormal situation arises, how-

ever, due to line interruption, no alarm

is sounded, causing extensive damage.

On the other hand, software is em-

ployed to set off the alarm in abnormal

circumstances, for example, if the dos-

ing terminals are closed for too long a

period. In both cases, the red LED’s will

also provide a visual warning signal.

The Fail Safe mode is accomplished by connecting the exter-

nal alarm circuit between the FS•C (Normally Open) and

the COM terminals. This way, an alarm will warn the user

when pH goes over the alarm thresholds, the power breaks

down and in case of a broken wire between the process meter

and the external alarm circuit.

Note In order to have the Fail Safe feature activated, an external

power supply has to be connected to the alarm device.

CONTROL THROUGH ANALOG OUTPUT

Models pH5025YZ and mV6025YZ have a proportional out-

put signal (selectable among 0-1mA, 0-20mA, 4-20mA,

0-5VDC, 1-5VDC and 0-10VDC) at the analog output ter-

minals. With this output, the actual output level amplitude is

varied, rather than the proportion of ON and OFF times

(duty cycle control). A device with analog input (e.g. a pump

with a 4-20 mA input) can be connected to these terminals.

Note Models with this feature don’t have the output relay for a duty

cycle control.