Cleaning and maintenance, Technical specifications – Velleman DVM439 User Manual
Page 5

DVM439
V. 02 – 14/10/2013
5
©Velleman nv
‘Er2’ is displayed when the device is exposed to rapid changes
in ambient temperature. Allow the device to reach the ambient
temperature for at least 30 minutes.
‘Er3’ is displayed when the ambient temperature is outside of
the
0–50 °C range (32–122 °F). Allow the device to reach the
ambient temperature for at least 30 minutes.
Er5–9. For all other errors, it is necessary to reset the device.
To reset, proceed as follows:
1. Wait until the device powers off automatically (about 15 s).
2. Remove the batteries and wait for at least 1 minute.
3. Reinsert the batteries and press the measurement button.
Note: If the error persists, contact your dealer for service.
9. Cleaning and Maintenance
The sensor lens [3] is the most delicate part of the device and it shall be
kept clean at all times. To do this, only use a soft cloth or cotton bud
with a little water or medical alcohol.
Allow the lens to fully dry before using the device.
Wipe the other parts of the device regularly with a moist, lint-free cloth.
Do not use alcohol or solvents.
Do not submerge the device in water or any other liquid.
There are no user-serviceable parts. Contact your dealer for spare parts
if necessary.
The device shall be stored between –20 °C and +65 °C (–4 °F to
+149 °F).
10. Technical Specifications
measurement range
–35 °C to 365 °C (–31 °F to 689 °F)
operating temperature
–10 °C to 50 °C (32 °F to 122 °F)
storage temperature
–20 °C to 65 °C (–4 °F to 149 °F)
accuracy
T
obj
= –35 °C to 0 °C T
amb
= 23–25 °C ± (2.5 °C + 0.05/degree)
T
obj
= 0–365 °C
T
amb
= 23–25 °C ± 2.5 % of reading + 2 digits
T
obj
= 15–35 °C
T
amb
= 25 °C
± 1.5 °C (2.7 °F)
resolution
(–9.9 °C to 199.9 °C)
0.2 °C / 0.5 °F
response time (90 %)
1 s
emissivity range
0.95 fixed
wavelength
5–14 µm
auto switching-off
15 s
distance-to-spot ratio D:S 8:1
power supply
2 x 1.5 V AAA batteries (incl.)