41
Subject to change without notice
Frequency and period
12
FREQ./PERIOD
Switching between frequency and period measurement by
repeatedly pressing this button. At measurement of DC voltage
the display shows “0 Hz“ for frequency and “INF“ for period
measurement (INF = infinity). As the period is calculated from
the measured frequency it is a division by zero.
There is no auto range function for frequency and
period measurements. That means the range of
the V
AC
measurement is taken. Is necessary to
measure the alternating voltage in V
AC
first and
afterwards call up the FREQ./PERIOD function.
Temperature measurement
Switching between 2-wire and 4-wire measurement by
repeatedly pressing
ϑ
PT-button
13
. This is indicated in the
display by „2w“ for 2-wire and by “4w“ for 4-wire measurement.
Additionally the terminals to be used are illuminated. For
compensation of the wiring resistance at 2-wire measure-
ments 100 m
Ω
is stored by default. This value can be changed
via interface.
For exact measurements it is necessary to cali-
brate the measurement section with ZERO
. This
calibration is done for PT sensors by resistance
measurement or for thermocouples by voltage
measurement but not by temperature measure-
ment (see ZERO
).
13
ϑ
PT with 4-wire-temperature measurement
Measuring method:
4 wire resistance measurement with linearisation
according to EN60751 for PT100 and PT1000.
Temperature sensor:
PT100, PT1000 resistance sensors
Display range:
Display scale
Resolution
Celsius:
–200 °C to +800 °C
0.01 °C
Fahrenheit:
–328 °F to +1472 °F
0.01 °F
Test current:
PT100
1 mA
PT1000
100 µA
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
V
AC
Alternating voltage measurement up to 600 V, true RMS
without the DC component. In AC a capacitor is inserted. The
input impedance of the HM8112-3 is R
i
= 10 M
Ω
.
V
AC+DC
Alternating voltage measurement up to 600 V, true RMS with
DC component. Direct coupling of the circuit to the instrument
and using of the same high precision input divider like V
DC
.
The input impedance of the HM8112-3 is 10 G
Ω
in 100 mV
range, 10 M
Ω
in the other ranges.
Current
measurement
A
DC
Direct current
measurement.
Auto range func-
tion up to and
including
the range 1 A
A
AC+DC
Alternating current measurement, true RMS with DC com-
ponent. Auto range function over the entire range of 1 A.
Resistance measurement
Switching between 2 wire and 4 wire measurement by repeatly
pressing
Ω
-button
11
. This is shown in the display by „2w“ for
2 wire and by „4w“ for 4 wire measurement. Additionally the
terminals to be used are illuminated. For exact measurements
it is necessary to null any offsets by pressing ZERO
.
11
Ω
2-wire
resistance
measurement
For compensation
of the wiring resis-
tance with 2-wire
measurements
100 m
Ω
is stored by
default. This value
can be changed via
the interface.
11
Ω
4-wire
resistance
measurement
V
A
SENSE
SOURCE
LO
HI
max.
250Vrms
max.
850
Vpk
max.
850
Vpk
Ω
,
ϑ
FUSE
1A
F250V
CAT
II
max. INPUT
600Vrms / 1Arms
+
–
Power
input
(Source)
+
–
Voltage
measurement
(Sense)
Resistance measurement
4-wire
V
A
SENSE
SOURCE
LO
HI
max.
250Vrms
max.
850
Vpk
max.
850
Vpk
Ω
,
ϑ
FUSE
1A
F250V
CAT
II
max. INPUT
600Vrms / 1Arms
+
–
resistance
measurement
2-wire
STOP
STOP
V
A
SENSE
SOURCE
LO
HI
max.
250Vrms
max.
850
Vpk
max.
850
Vpk
Ω
,
ϑ
FUSE
1A
F250V
CAT
II
max. INPUT
600Vrms / 1Arms
+
–
Direct or
alternating voltage
V
A
SENSE
SOURCE
LO
HI
max.
250Vrms
max.
850
Vpk
max.
850
Vpk
Ω
,
ϑ
FUSE
1A
F250V
CAT
II
max. INPUT
600Vrms / 1Arms
+
Direct or alter
Direct or alter
Direct or alter
Direct or alter
Direct or alter-----
nating current
nating current
nating current
nating current
nating current
–
V
A
SENSE
SOURCE
LO
HI
max.
250Vrms
max.
850
Vpk
max.
850
Vpk
Ω
,
ϑ
FUSE
1A
F250V
CAT
II
max. INPUT
600Vrms / 1Arms
+
–
Power
input
(Source)
+
–
4-wire-temperature measurement with PT100
Voltage
measurement
(Sense)
Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176
FAX 781.665.0780 - TestEquipmentDepot.com
