53
Subject to change without notice
Frequency and period
12
FreQ./PerioD
Switching between frequency and period measurement by re-
peatedly 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 repea-
tedly pressing
δ
PT-button
13
. This is indicated in the display by
„2w“ for 2-wire and by “4w“ for 4-wire measurement. Additional-
ly the terminals to be used are illuminated. For compensation of
the wiring resistance at 2-wire measurements 100 mΩ 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
4
. this
calibration is done for Pt sensors by resistance
measurement or for thermocouples by voltage
measurement but not by temperature measure-
ment (see Zero
4
).
13
δ
Pt with 4-wire-temperature measurement
measuring method:
4 wire resistance measurement with linearisation accor-
ding 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
Test voltage
(open circuit):
2.5 V
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
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
Direct voltage measurement up to 600 V. No auto range function
in 100 mV and 1 V ranges.
8
V
Ac
Alternating voltage measurement up to 600 V, true RMS wit-
hout the DC component. 100mV range is not possible. In AC a
capacitor is inserted. The input impedance of the HM8112-3 is
R
i
= 10 MΩ.
10
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 GΩ in 100 mV range,
10 MΩ in the other ranges.
current measurement
7
A
Dc
Direct current
measurement.
Auto range func-
tion up to and
including
the range 1 A
9
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
4
.
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
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-
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)
