This displays the hardware version number (the 3 digits before the point) and the
software version number (the 3 digits after the point) followed by the serial number
corresponding to the type label. The month and year of the last calibration are dis-
played (cf. Section 9) along with the memory capacity.
By pressing the ON-OFF button again the VM25 switches itself off. In addition, the
instrument has an automatic shut-off timer for saving the battery power (cf. Chapter
4.4).
4.3. Battery Display and Battery Type
In the upper left corner of the VM25 display there is a battery level indicator (10).
When the green battery symbol is full, the battery is fully charged.
While non-rechargeable batteries have a cell voltage of 1.5 V, NiMH rechargeable
batteries deliver only 1.2 V per cell. The VM25 battery indicator can be adjusted to
both voltages. To adjust the voltage, open the main menu by pressing F3 and scroll
through the menu options by repeatedly pressing the ▼ button until you reach 'In-
strument Settings', then press OK.
Within the sub-menu select “Battery type” (Figure 11) by following the same in-
structions as before and then by pressing▼ select between “Alkaline” (non-
rechargeable, 1.5 V) or “NiMH accu” (rechargeable, 1.2 V). Confirm your choice by
pressing OK and exit the menu by pressing F3 repeatedly.
If the power supply drops below 3.3 V when using alkaline batteries or below 3 V
with rechargeable batteries, the battery indicator becomes red. Further measurements
can be taken until the power supply reaches 2.8 V in keeping with the instrument
specifications. At this point the battery level indicator is completely empty and the
instrument switches itself off automatically.
If the VM25 is connected to a USB port, it will be supplied by the USB voltage in
order to spare the batteries. In this case, “external” is displayed on the screen instead
of the battery level indicator.
11
Figure 10: Battery indica-
tor upper left
Figure 11: Select battery type
