External DC Voltage Supply
7.3 External DC Voltage Supply
It is also possible to connect another DC voltage (6-12 volts ±5%, minimum
800 mA) to socket DC (5). This must be connected using a low-voltage con-
nector (NES1 as per DIN 42323) with its center pin to minus. If, however, the
power supply has to be electrically isolated from the transducers or if a larger
input voltage range (10-30 volts) is required, then electrically isolated supply
cable ZB 2590-UK must be used. It will then be possible to use the measuring
instrument in a 12-volt or 24-volt on-board supply system.
7.4 Sensor Supply
At the ter (plus) and - (minus) in the ALMEMO
®
connector there is a
configurable sensor supply voltage available (self-healing fuse, 500 mA). The
sensor is programmed by default to 9 volts (150 mA); it can if necessary be
programmed in the
power supply
menu to 12 volts (100 mA) instead. (see
10.7) In mains operating mode the sensor voltage is set automatically to 12
volts. Other voltages (12, 15, or 24 volts or references for a potentiometer and
strain gauge) can be obtained using special connectors.
(see Manual. Sections 4.2.5 and 4.2.6)..
7.5 Switch On/Off, Reinitialisation
To switch on or off use the slide switch (1) located on the left side of the de -
vice.
●
up
ON
●
down
OFF
The measuring menu most recently selected always appears first in the dis-
play.
After the device is switched off the real-time clock continues to run and all
saved values data and settings are retained intact. (see 6.6).
If interference (e.g. electrostatic) or a malfunction (e.g. battery failure) causes
the device to behave abnormally, the device can be reinitialized. You can acti-
vate this reset by pressing key
F1
r
when switching on. You can restore all de-
vice programming (including times, device designation, user menus, etc.) to
the factory default settings by pressing key
F4
when switching on. Only the
programming of the sensors in the ALMEMO
®
connectors remains unaffected.
7.6 Data buffering
The sensor programming is stored in the EEPROM of the sensor connector,
the calibration and the programmed parameter of the device is fail-safe stored
in the EEPROM of the device. Time and date are buffered by a lithium battery
so that storage of the data is also guaranteed without batteries and when the
device is switched off.
ALMEMO
®
2890-9
17