Continuity Test; Max / Min Values; Range Selection - Hameg HM8112-3 Benutzerhandbuch

C o n t r o l e l e m e n t s a n d d i s p l a y
Measurement
period: 100 ms to 60 s
Delay: 100 ms (after change of function or range)
Calibration: with resistance measurement standard
PT100
PT1000
Linearisation: according to EN60751
δPT with 2-wire-temperature measurement
13
Limited accuracy of measured values for 2-wire-temperature
measurement with platinum temperature sensors PT100 or
PT1000.
max. INPUT
600V / 1A
rms
V
SENSE
max. max.
850 850
Vpk Vpk
Adjustment of measuring section with PT sensor
PT sensors have an output resistance which is mostly referred
in the data sheet. Often the data sheet is lost but the sensor is
still there. In HM8112-3 a value of 100 mΩ is stored by default.
But some PT sensors have an integrated series resistance
(e.g. 10 mΩ). For an optimal adjusted measuring section the
exact output resistance must be known. This applies for 4-wire
measurement but especially for 2-wire measurements. Via
interface the default value stored ex factory can be aligned.
Values between 0 mΩ and 100 mΩ are possible.
Determination of the output resistance
The PT100 or PT1000 sensor has to be immersed in an ice
bath. At 0 °C the sensor has a resistance of 100Ω and 1000Ω
respectively. The resistance of the temperature sensor is taken
by a resistance measurement. The output resistance is the
difference between the measured value and the specified value.
15 δTH temperature measurement with thermocouples
+
thermo-
max.
couples
850
Vpk
–
Measuring method: Voltage measurement in 100 mV
range with linearisation according to
EN60584.
Display range: Thermocouples
J- Type (Fe-CuNi)
K – Type (NiCr-Ni)
Resolution:
0.1 °C / °F
Measurement period: 100 ms to 60 s
Delay:
100 ms (after change of function)
Display:
Dimension °C or °F
Linearisation:
according to EN60584
54
Subject to change without notice
1 kΩ range
10 kΩ range
FUSE
1A
rms
F250V
A
SOURCE
Power
input
+
HI
ϑ (Source)
Ω,
–
LO
max.
250V rms
II
CAT
FUSE
max. INPUT
1A
600V / 1A
rms rms
F250V
V A
SENSE SOURCE
HI
max.
ϑ
Ω,
850
Vpk
LO
max.
250V rms
II
CAT
Range up to °C
–210 to +1200
–270 to +1372

10.3 Continuity test

14 Continuity and diode test
max. INPUT
600V / 1A
rms rms
V
SENSE
max. max.
850 850
Vpk Vpk
250V rms
Continuity test:
Activating of the loudspeaker for measured values between
0 Ω (short-circuit) and approx. 10 Ω.
Diode test:
Test voltage approx. 2.5 V
Test current 1 mA constant
Max. forward voltage 1.2 V, otherwise
"Overflow V
The test unit must be at zero potential during conti-
nuity test.

10.4 Max / Min values

16 MAX / 17 MIN
The maximum or minimum measured value is displayed. As
this is possible in every measurement function, a system can
be controlled with respect to min/max values. There is no time
limitation, e.g. for activating this function for one year, the
minimum or maximum value measured during this year will
be displayed. This function is deactivated by pushing the keys
MAX 16 or MIN 17 again. Changing the measurement function
will deactivate this function, too.

10.5 Range selection

Manual range selection
The range can be selected manually by pressing
Switch to a lower range. The auto range function will be
deactivated.
Switch to a higher range. The auto range function will be
deactivated.
If the applied measurement value exceeds the range, the display
will show „Overflow".
21 AUTO
With button AUTO the auto range function can be activated.
This function is selectable for voltage, current and resistance
measurements.
As the autorange function is activated a higher range will be
selected after the measured value exceeds 90% of full scale. The
HM8112-3 will change to a lower range, if the value falls below
10% of full scale. If the signal applied exceeds the specified
limits of the instrument in the autorange function, the display
shows "overflow".
FUSE
1A
F250V
A
SOURCE
+
HI
Continuity
test
ϑ
Ω,
–
LO
max.
II
CAT
" is displayed.
DC
20 and 23 .