3. POWER SUPPLY
The following options are available for the power supply of the instrument:
Mains supply unit or battery charger 12V/2A (s. 3.1)
ZB 5090-NA3
NiCd batt. pack 7.2V built-in (Option A, s. 3.2)
OA 5990-A
galv. getr. DC Voltage Supply (Option U, s. 3.3)
OA 5990-U
3.1 Mains Operation
The mains adapter ZB 5090-NA3 to 12VDC, 2A, is used for the power supply
of the measuring instrument. It is connected to the socket U-DC (7d) and is
locked by turning it to the right.
It is also possible to insert the banana plug (with the protective ground connec-
tor for interference suppression) into the adjacent bare socket.
It is only in exceptional cases (e.g. in an industrial environment) that the protec-
tive ground may itself be subject to such high voltage peaks that it is better to
dispense with this connection.
3.2 Accu. battery mode, supply voltage monitoring
With option A, a rechargeable NiCd accumulator battery, 7.2 V with 1.5 Ah, is
installed; at a power draw of approx. 65mA, this gives uninterrupted operation
of around 23 hours. If selector switch boards (approx. 12mA) are installed or
sensors are connected that need additional power (e.g. humidity sensor
FH-A646 2mA, or rotating vanes, approx. 3mA) or the serial interface is active
(4mA), this operating time will be accordingly shorter. If lighting is left switched
on permanently, the operating period will be reduced to approx. 14 hours.
One way of prolonging the operating time is to switch off the display; (see Sec-
tion 8.6). As soon as the battery’s residual capacity drops to around 10 per-
cent, the “
“ symbol appears in the status line of the display. Normally at
this juncture the battery should be recharged using the mains adapter supplied
with the device; further delay may result in critically low discharge and this may
damage the battery. The battery voltage (and thus an estimate of the operat-
ing time left) can be determined using a ´Batt´ measuring channel.
So long as the device is running on battery only, the green indicator lamp PWR
(4) does not light up at all. The battery should be charged using the 12V net-
work adapter ZB-5000-NA3; this can completely recharge an empty battery in
2.5 hours. During this charging time the green lamp lights up continuously to
indicating that charging is in progress.
Please note that during the charging process the build-up of heat in
the device may result in thermocouple measuring operations with in-
ternal cold junction compensation being falsified.
As soon as the battery is fully charged, the green indicator lamp starts blinking
and the device switches over to trickle charge. The mains unit can thus be left
permanently connected to the measuring instrument in float mode.
ALMEMO
®
5990-2
13
Power Supply
Summary of Contents for ALMEMO V5 5990-2
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