Hold Mode - Hanna Instruments HI504 Instruction Manual

HOLD MODE

There are two digital insulated inputs: one for hold mode and one for advanced cleaning .
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This function is started by:
• calibration;
• setup;
• cleaning in place;
• the hold digital insulated input
the signal level is polled at least every 4 seconds;
• the proper key combination ( and  keys together) for
service; the same key combination is used both to start
and to stop the hold mode (the key combination acts as
the hold digital input) . To activate the hold mode in this
way, password is required;
• the daily programmable control timing (see setup items
C .41 through C .57);
• an error event (see also the "Alarm - Error Configuration"
section);
• the hold start/stop RS485 command;
• the service hold (Calibration and Setup) in the Digital
Transmitter .
During hold mode, control and control relays are disabled .
If the meter is in idle or control mode
and displaying measurements, the
last measured value (both for tem-
perature and pH/ORP) is frozen on
the display; the secondary LCD shows
"HLd";
the temperature value can be displayed on the secondary
LCD by pressing and holding the  key; when the  key
is released the "HLd" message comes back on the second-
ary LCD .
If the pH or mV or temperature values
are not available because the meter
did note take any measurement be-
fore going to hold mode, then the
primary or the secondary LCD shows
dashes .
when it is on; normally,
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