Instructions

17
5 General Operation
General Operation
This section explains basic operation of the thermo-hygrometer. Detailed operation of the
thermo-hygrometer is explained in Sections 7 and 8 of the User’s Guide. Section 7 explains
the menu structure and the functions available in the menu structure and Section 8 explains the
communications interface for operating the thermo-hygrometer remotely.
DC Power Source
The thermo-hygrometer requires 12 V dc to operate. The ac adapter is provided to produce the
DC power from an AC mains supply.
CAUTION: For CE compliance and for proper performance, use only the AC adapter
shipped with the instrument by Hart Scientific. If the AC adapter needs to be replaced,
contact Hart Scientific Authorized Service Center. The AC adapter has circuits with high
voltages inside that could present danger of electric shock or fire if exposed. If the AC
adapter is damaged in any way or becomes hot, discontinue use immediately, disconnect
the adapter from any AC supply, and replace the adapter. Do not attempt to open, repair,
or continue using a damaged or defective AC adapter.
The DC output from the AC adapter plugs into the 12 V dc power input on the left side of the
instrument (see Figure 3 on page 13).
Battery
The thermo-hygrometer uses a 9 V battery to maintain continuous measurement and recording
during power outages. The recommended battery type is a standard 9 V alkaline battery (NEDA
1604A or IEC 6LR61). During a power outage, or when the ac adapter is disconnected, the dis-
play will be inoperable but measuring will continue if the 9 V battery is installed. If the alarm is
enabled, the beeper will sound periodically to alert the user of the loss of external power. With
a fresh alkaline battery, measuring will continue during a power outage for typically about 16
hours. During normal operation, the battery charge is regularly checked, and if the low battery
alarm is enabled, the user will be alerted when the battery charge drops below approximately
50 %. The battery charge level can be viewed with a display layout that includes a stat type
zone with one of the fields set to BATT. To prevent inadvertent battery drain, remember to
switch the power switch off when external power is disconnected and the thermo-hygrometer is
not in use.
To install or replace the battery, follow these steps:
Switch the power off and unplug the dc power cord.
Turn the thermo-hygrometer over to access the rear battery compartment. Press down
slightly on the battery cover and slide it out to remove it.
Remove the old battery if one is in place by lifting it up at the bottom and pulling it out.
Slide the new battery in at an angle, observing the proper polarity so the terminals mate
correctly, then press the bottom of the battery down into the holder.
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