6½-Digit Precision multimeter Hm8112-3

6½-Digit Precision multimeter Hm8112-3
A l l g e m e i n e H i n w e i s e z u r CE - K e n n z e i c h n u n g Hersteller
Manufacturer
Fabricant
Die HAMEG Instruments GmbH bescheinigt die Konformität für das Produkt
The HAMEG Instruments GmbH herewith declares conformity of the product
HAMEG Instruments GmbH déclare la conformite du produit
Überspannungskategorie / Overvoltage category / Catégorie de surtension: II
Bezeichnung / Product name / Designation:
Präzisions-Multimeter
Precision Multimeter
Multimétre de précision
Elektromagnetische Verträglichkeit / Electromagnetic compatibility /
Compatibilité électromagnétique
Typ / Type / Type:
HM8112-3
mit / with / avec: HO820
Optionen / Options / Options: HO880
mit den folgenden Bestimmungen / with applicable regulations / avec les directives
suivantes
EMV Richtlinie 89/336/EWG ergänzt durch 91/263/EWG, 92/31/EWG
EMC Directive 89/336/EEC amended by 91/263/EWG, 92/31/EEC
Directive EMC 89/336/CEE amendée par 91/263/EWG, 92/31/CEE
Niederspannungsrichtlinie 73/23/EWG ergänzt durch 93/68/EWG
Low-Voltage Equipment Directive 73/23/EEC amended by 93/68/EEC
Directive des equipements basse tension 73/23/CEE amendée par 93/68/CEE
Angewendete harmonisierte Normen / Harmonized standards applied / Normes
harmonisées utilisées
Sicherheit / Safety / Sécurité
EN 61010-1:2001 (IEC 61010-1:2001)
EN 61326-1/A1 Störaussendung / Radiation / Emission:
Tabelle / table / tableau 4; Klasse / Class / Classe B.
Störfestigkeit / Immunity / Imunitee: Tabelle / table / tableau A1.
EN 61000-3-2/A14 Oberschwingungsströme / Harmonic current emissions / Émissions
de courant harmonique:
Klasse / Class / Classe D.
EN 61000-3-3 Spannungsschwankungen u. Flicker / Voltage fluctuations and flicker /
Fluctuations de tension et du flicker.
Datum /Date /Date
01.12.2004
I n h a l t s v e r z e i c h n i s
English35
2
6½-Digit Precision-Multimeter HM8112-3
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8.3
8.4
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H M 8 1 1 2 - 3 HM8112-3
R
R
R
R
R
R
R
R
R
R
R
R
R
4
T e c h n i s c h e D a t e n
6½-Digit Präzisions-Multimeter
HM8112-3 [HM8112-3S]
23°C ±2 °C
% f.s.
0,0006
0,0006
0,0006
0,0006
0,0006
0,1 s
120,000 Digit
60,000 Digit
1 µV
Temp. Koeffizient
10…21 °C + 25…40 °C
0,0008
0,0008
0,0008
0,0008
0,0008
1…60 s
1.200,000 Digit
600,000 Digit
100 nV
100 Ω, 1 kΩ, 10 kΩ, 100 kΩ, 1 MΩ, 10 MΩ
0,1s1…60s
120,000 Digit
1.200,000 Digit
1 mΩ
100 µΩ
Mess-Strom:
23 °C ±2 °C
% f.s.
0,0015
0,001
0,001
0,001
0,002
0,02
Temp. Koeffizient/°C
10…21 °C
25…40 °C
0,0008
0,0008
0,0008
0,0008
0,0008
0,0008
0,0008
0,0008
0,002
0,002
0,01
0,01
**)
5
1.3Transport
(1) (2) (3) (4) Symbol 1:
Symbol 2:
Symbol 3:
Symbol 4:
Symbol 5:
Symbol 6:
(5) (6)
Bild 1
Bild 2
Bild 3
–
–
–
–
–
–
W i c h t i g e H i n w e i s e
CAT III
7
8
B e z e i c h n u n g d e r B e d i e n e l e m e n t e
2
3 4
5
1
6
7
8
27
9
10 11
12 13
14 15
16 17
19 20
18 21
22 23
24
25
26
/ Parameter
men
20 5 RM/LOCAL-Taste –
23 Logger-Menü
stands-, Temperaturmessung
14 30
9
M e s s g r u n d l a g e n 1 2,6 0 0 0 0 V
1 2,6 0 0 0 0 V
1 2,6 0 0 0 0 1 2,6 0 0 0
6-stelliges DMM
6½-stelliges DMM 6¾-stelliges DMM
0 0 0 0 0 0
0 0 0 0 0 0 0
bisbisbis
0000000
1999999
3999999
9 9 9 9 9 9
Messpunkte:
1.0 0 0.0 0 0 Digit 2.0 0 0.0 0 0 Digit 4.0 0 0.0 0 0 Digit
1 0 V
1 0 V
10V
1 0,0 0 0
1 0,0 0 0 0 0
1 0,0 0 0 0 0
2 0 V
2 0 V
20V
2 0,0 0 0
2 0,0 0 0 0
2 0,0 0 0 0 0
3 9,9 9 9 9 9 V
3 9,9 9 9 9 9 V
3 9,9 9 9 9 9 V
3 9,9 9 9
3 9,9 9 9 9
3 9,9 9 9 9 9
4 0 V
4 0V
40V
4 0,0 0 0
4 0,0 0 0 0
4 0,0 0 0 0
6½-stelliges DMM1
6½-stelliges DMM2
0 0 0 0 0 0 0
0000000
bis
bis
1999999
1250000
Messpunkte:
2.0 0 0.0 0 0 Digit
1.2 5 0 0 0 1 Digit
1 0 V
10V
1 0,0 0 0 0 0
1 0,0 0 0 0 0
1 2,5 0 0 0 0 V
1 2,5 0 0 0 0 V
1 2,5 0 0 0 0
1 2,5 0 0 0 0
10
12,50000 V
2,50000 V
10,00000 V
M e s s g r u n d l a g e n
0110
0110
0101
0101
0100
0011
0001
0001
Ue
Z(Ue)
0110
0101
0101
0100
0100
0011
0010
0010
0001
Ue
Ue
0011
0011
0010
0010
0110
0001
Ue
Ue
Ue
Ue
11
Name: Single Slope
M e s s g r u n d l a g e n U
U
r
Ue = Uref
0V
t1
t
t2
Abb. 5: Single-Slope
t1 = const.
*
U r1
t2
U r1
Ur
t1 = const.
t2
0V
t
t3
U r1
t1
U r2
0V
t
t3
t1
t2
t3
Abb. 6: Dual-Slope Prinzip
t2
t3
t2
t3
Ur
#Uedt
Auto-Zero
#Urefdt
U r1
U r1
0V
t
t0
Phase 1
t1
Phase 2
t2
Phase 3
4 5
Phase 1
t3 t4 t5/0
t1
Abb. 8: Multi-Slope
13
G l e i c h s p a n n u n g s s m e s s u n g Rq
Kontakt 1
bei T1
DMM
Material 1
U0
Ri =
Rq =
U0 =
Ri
V Um
DMM
Uo
V
Material 1
Kontakt 2
bei T2
Um
W i d e r s t a n d s m e s s u n g
DMM
RL
R
RL1
RL1
V
Um
Im
RL
RL
DMM
R
V
RL
Um
Im
15
T
0
I_
I_
1 TTTTT
I_
I_
11
I_
IxI(t)
=—
—
∫IxIx
Ix(t)
dt
1
(t) =
(t)III ··· dt
1 ∫
IxI
=
—
dt
IxI
(t)
(t)
IxI
=
—
(t)
IxI(t) = —
Ix(t)
dt
(t)II ·· dt
TTTT 0000∫ Ix
T
0
0
0
0 00
0
t ttttt
IuI
IuI
IuIIuI
IuI
IuI
t ttttt
T
π
0
1 TTTTT 22
1
11
—
∫xxx(t)(t)(t)(t)222|||| ···· dtdt
dt
1 ∫
—
—
—
—
x(t) | · dt
dt
TTTT 0000∫x
xeff
=
eff =
x
=
xx
eff
xeff
=
eff =
T
0
T
0
2
u2 (t)
Ueff
0
t
u(t)
Rq
DMM
RL
U0
R
V
Crest-Form-
faktorfaktor
C F
2
2
2
p
2 2
= 1,11
p
= 1,11
2 2
p
2
= 1,57
7Temperaturmessung
3
2
3
= 1,15
0 K
255,38 K
273,15 K
373,15 K
Celsius (°C)
-273,15 °C
-17,77 °C 0 °C
100 °C
17
T e m p e r a t u r m e s s u n g Umrechnung
°C in K: T[K] =
°K in °C: T[°C] =
°C in °F: T[°F] =
°F in °C: T[°C] =
T[°C] +273,15 K
T[K] –273,15 K
9/5 x (T[°C] +32 °F
5/9 x (T[°F] –32 °F)
RL
FUSE
1A
F250V
max. INPUT
600V rms / 1A rms
V
A
SENSE
HI
max. max.
850 850
Vpk Vpk
Ω, ϑ
max.
250Vrms
LO
PT100
CAT II
RL
7.3Temperaturmessung mit PT100 / PT1000
FUSE
1A
F250V
max. INPUT
600V rms / 1A rms
V
A
Messstrom IPT100 = const
SENSE
Draht Ni
–1,9 mV/100K
HI
max. max.
850 850
Vpk Vpk
Ω,ϑ
max.
250Vrms
LO
PT100
CAT II
ITherm
IDiffusion
KS2
Kontaktstelle KS2
Temperatur TKS2 <TKS1
Temperatur
TMess
Cu-Leitung
TRef = const
Isothermalblock
Referenzstelle KS2
TReferenz = const
19
G e r ä t e k o n z e p t d e s H M 8 1 1 2 - 3 B e d i e n e l e m e n t e u n d A n z e i g e n
2
3 4
5
27
1
6
7
8
9
10 11
12 13
14 15
16 17
19 20
18 21
22 23
24
25
26
21
PT100
Ω 2-WIRE / Ω 4-WIRE
PT1000 Ω 2-WIRE / Ω 4-WIRE
Thermoelement VDC
FUSE
1A
F250V
max. INPUT
600V rms / 1A rms
V
+
–
Strommessung
max.
250V rms
LO
FUSE
1A
F250V
max. INPUT
600V rms / 1A rms
V
7 ADC
A
SENSE
max. max.
850 850
Vpk Vpk
HI
+
LO
–
Ω, ϑ
max.
250V rms
CAT II
FUSE
1A
F250V
max. INPUT
600V rms / 1A rms
V
A
SENSE
max. max.
850 850
Vpk Vpk
+
LO
–
2-Draht
max.
250V rms
CAT II
FUSE
1A
F250V
V
A
max. max.
850 850
Vpk Vpk
SENSE
+
–
HI
Ω, ϑ
max. INPUT
600V rms / 1A rms
(Sense)
Ω, ϑ
CAT II
22
Spannungsmessung
HI
max. max.
850 850
Vpk Vpk
A
SENSE
HI
+
LO
–
(Source)
Ω, ϑ
max.
250V rms
CAT II
B e d i e n e l e m e n t e u n d A n z e i g e n
Frequenz und
Periodendauer
FUSE
1A
F250V
max. INPUT
600V rms / 1A rms
V
A
SENSE
+
HI
max. max.
850 850
Vpk Vpk
–
Ω, ϑ
max.
250V rms
LO
CAT II
FUSE
1A
F250V
max. INPUT
600V rms / 1A rms
V
A
SENSE
V
(Source)
+
(Sense)
–
CAT II
HI
max. max.
850 850
Vpk Vpk
LO
FUSE
1A
F250V
max. INPUT
600V rms / 1A rms
+
V
(Source)
Ω, ϑ
max.
250V rms
A
SENSE
–
+
CAT II
ThermoElement
–
4-Draht-Temperaturmessung mit PT100
HI
max. max.
850 850
Vpk Vpk
Ω, ϑ
max.
250V rms
–
LO
A
SENSE
+
Ω, ϑ
15 δTH – Temperaturmessung mit Thermoelementen
FUSE
1A
F250V
max. INPUT
600V rms / 1A rms
HI
max. max.
850 850
Vpk Vpk
max.
250V rms
LO
CAT II
23
max. INPUT
600V rms / 1A rms
V
A
SENSE
max. max.
850 850
Vpk Vpk
HI
+
LO
–
Ω, ϑ
max.
250V rms
CAT II
MENU
MENU
0: Time
60s
10s
1s
500ms
100ms
MENU
MENU
default
16
8
4
2
Off
MENU
MENU
default
MENU
°F
°C
MENU
last setting
K
J
PT1000
PT100
Comp
MENU
MENU
default
MENU
Comp PT-Front
MENU
Comp Ext/Ice
Comp PT-Front
Comp 23°C/°F
MENU
MENU
Status-Information
Auswahl
4: Info
MENU
MENU
25
➡
5: Math
MENU
➡
➡
MENU
default
➡
MENU
➡
➡
Start
Stop
Dump
Dump
➡
MENU
➡
00000
➡
ENTER
ENTER
➡
MENU
default
➡
➡
Wert1 00001
➡
➡
Wert2 00002
Storage End
MENU
oder
ESC
Rs19200
Rs9600
Off
➡
MENU
mit
➡
MENU
➡
last setting
➡
MENU
➡
empty
Chanal 1
....
Chanal 8
26
➡
default
MENU
Menü verlassen
M e n ü s t r u k t u r
27
M e s s - E i n g ä n g e Hi Limit
Stop
Dump
24
25
26
27
S e r i e l l e S c h n i t t s t e l l e
29
28
30
VHI
AHI
VHI
AHI
VHI
AHI
VHI
AHI
VHI
AHI
VHI
AHI
VHI
AHI
VHI
AHI
VHI
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
19
37
ALO
36
VLO
BP
35
ALO
34
VLO
CH1
33
ALO
32
VLO
CH2
31
ALO
30
VLO
29
ALO
CH3
28
VLO
CH4
27
ALO
26
VLO
CH5
25
ALO
24
VLO
CH6
23
ALO
22
VLO
CH7
21
ALO
20
VLO
CH8
29
30
0
2
1
0
2.
Gruppe
1.
0,1mA
100Ohm
3 IAC
4 OHM 2WIRE
-
-
F Sensor TH
-
-
LENGTH
F Info - data read
-
2 Com
C MESSAGE
-
OFF
F TEST
-
EXT/ICE
C Sensor Comp
OFF
START
STOP
9 Storage
A BUFFER
LAST CAL
GROUP 1
-
-
RAM
23°C
1
ON
-
-
ZERO
-
7 ZERO
OFFSET
2
10ms
ON
J
8 Temp
OFF
AUTO
4 Math
CONT
6 TRIGGER
1 MEAS-Time
OFF
-
0 AUTO-RANGE
-
-
C Durchgang
-
-
FREQ
-
1kOhm
1kOhm
1mA
1mA
1V-DC
1V
1
100Ohm
0,1mA
2 IDC
5 OHM 4WIRE
100mV
100mV-DC
1 VAC
0
0 VDC
GROUP 2
-
-
FRONT
2
DUMP
DUMP
-
-
-
HIGH LIMIT
4
50ms
-
K
-
-
-
-
PERIOD
10kOhm
10kOhm
10mA
10mA
10V-DC
10V
2
-
9600
-
-
3
-
-
-
LOW LIMIT
8
100ms
-
-
Pt100
Pt100
-
-
-
100kOhm
100kOhm
100mA
100mA
100V-DC
100V
3
-
-
AUTO STATE
19200
-
4
CLEAR
CLEAR
°C
-
-
-
16
500ms
-
-
-
-
-
-
-
1MOhm
1MOhm
1A
1A
600V-DC
600V
4
-
-
CONT STATE
-
RAM FAIL
-
5
AUTO CLEAR
°F
-
-
-
-
1s
-
-
Pt1000
Pt1000
-
-
-
10MOhm
10MOhm
-
-
-
-
5
-
-
-
-
-
-
6
-
-
-
-
-
10s
-
-
-
-
10 Ohm
-
-
-
-
-
-
1V-AC
-
6
-
-
-
-
-
-
8
-
-
-
-
MAX
-
60s
-
-
-
-
-
-
-
-
-
-
-
10V-AC
-
7
-
--> E
-
-
-
-
-->
-
-
-
-
-
MIN
-
UP
UP
-
-
-
-
-
-
-
-
-
-
100V-AC
-
8
9
-
-
-
-
-
F
-
-
-
-
-
-
-
DOWN
DOWN
-
-
-
-
No Change
-
No Change
No Change
No Change
No Change
600V-AC
No Change
5.
LF
oder
CR
B e f e h l s l i s t e D a t e n ü b e r t r a g u n g
31
33
G e n e r a l r e m a r k s r e g a r d i n g t h e CE m a r k i n g Hersteller
Manufacturer
Fabricant
Die HAMEG Instruments GmbH bescheinigt die Konformität für das Produkt
The HAMEG Instruments GmbH herewith declares conformity of the product
HAMEG Instruments GmbH déclare la conformite du produit
Überspannungskategorie / Overvoltage category / Catégorie de surtension: II
Elektromagnetische Verträglichkeit / Electromagnetic compatibility /
Compatibilité électromagnétique
Typ / Type / Type:
HM8112-3
mit / with / avec: HO820
Optionen / Options / Options: HO880
mit den folgenden Bestimmungen / with applicable regulations / avec les directives
suivantes
EMV Richtlinie 89/336/EWG ergänzt durch 91/263/EWG, 92/31/EWG
EMC Directive 89/336/EEC amended by 91/263/EWG, 92/31/EEC
Directive EMC 89/336/CEE amendée par 91/263/EWG, 92/31/CEE
Niederspannungsrichtlinie 73/23/EWG ergänzt durch 93/68/EWG
Low-Voltage Equipment Directive 73/23/EEC amended by 93/68/EEC
Directive des equipements basse tension 73/23/CEE amendée par 93/68/CEE
Angewendete harmonisierte Normen / Harmonized standards applied / Normes
harmonisées utilisées
Sicherheit / Safety / Sécurité
EN 61010-1:2001 (IEC 61010-1:2001)
EN 61326-1/A1 Störaussendung / Radiation / Emission:
Tabelle / table / tableau 4; Klasse / Class / Classe B.
Störfestigkeit / Immunity / Imunitee: Tabelle / table / tableau A1.
EN 61000-3-2/A14 Oberschwingungsströme / Harmonic current emissions / Émissions
de courant harmonique:
Klasse / Class / Classe D.
EN 61000-3-3 Spannungsschwankungen u. Flicker / Voltage fluctuations and flicker /
Fluctuations de tension et du flicker.
Datum /Date /Date
01.12.2004
General remarks regarding the CE marking
Hameg measuring instruments comply with the EMI norms.
Our tests for conformity are based upon the relevant norms.
Whenever different maximum limits are optional Hameg will
select the most stringent ones. As regards emissions class 1B
limits for small business will be applied. As regards susceptability the limits for industrial environments will be applied.
All connecting cables will influence emissions as well as
susceptability considerably. The cables used will differ substantially depending on the application. During practical operation
the following guidelines should be absolutely observed in order
to minimize emi:
1. Data connections
Measuring instruments may only be connected to external
associated equipment (printers, computers etc.) by using
well shielded cables. Unless shorter lengths are prescribed
a maximum length of 3 m must not be exceeded for all data
interconnections (input, output, signals, control). In case an
instrument interface would allow connecting several cables
only one may be connected.
In general, data connections should be made using doubleshielded cables. For IEEE-bus purposes the double screened
cable HZ72 from HAMEG is suitable.
2. Signal connections
In general, all connections between a measuring instrument
and the device under test should be made as short as possible.
Unless a shorter length is prescribed a maximum length of 3 m
must not be exceeded, also, such connections must not leave
the premises.
34
Subject to change without notice
All signal connections must be shielded (e.g. coax such as
RG58/U). With signal generators double-shielded cables are
mandatory. It is especially important to establish good ground
connections.
3. External influences
In the vicinity of strong magnetic or/and electric fields even
a careful measuring set-up may not be sufficient to guard
against the intrusion of undesired signals. This will not cause
destruction or malfunction of Hameg instruments, however,
small deviations from the guaranteed specifications may occur
under such conditions.
HAMEG Instruments GmbH
General remarks regarding the CE marking
General remarks regarding the CE marking
34
6½-Digit Precision-Multimeter HM8112-3
36
Specifications
37
1Important hints
1.1Symbols
1.2Unpacking
1.3Positioning
1.4Transport
1.5Storage
1.6 Safety instructions
1.7 CAT II
1.8 Proper operating conditions
1.9 Warranty and Repair
1.10Maintenance
1.11 Mains voltage
1.12 Line fuse
1.13 Power switch
38
38
38
38
38
38
38
38
39
39
39
39
39
39
2Control elements
40
3Measurement Principles and Basics
3.1 Display of measuring ranges
3.2Overranging
3.3 Resolution of a measuring range
3.4 Measurement accuracy
3.5 Single-Slope A/D conversion
3.6 Dual-Slope A/D conversion
3.8 Accuracy specifications
41
41
41
41
41
43
43
44
4
4.1
4.2
4.3
4.4
4.5
45
45
45
45
45
46
DC measurements Input resistance for dc measurements
Series mode rejection
Common mode rejection Thermal voltages Interference by magnetic fields
5Resistance Measurement
5.1 Two-wire resistance measurement 5.2 Four-wire resistance measurement
5.3 Power dissipation of the resistors
46
46
46
46
6
6.1
6.2
6.3
6.4
6.5
47
47
47
47
47
47
AC measurement Basics of AC measurements
Arithmetic average value
Rectified value
Root-mean-square value
Form factor
7Temperature measurement 7.1 Temperature sensors
6.6 Crest factor
6.7 DC and AC currents 7.2 Platinum temperature sensor PT100
7.3 Temperature measurement with the PT100 / PT1000
7.4 NiCr-Ni thermocouple (K-Type)
7.5 Reference junction
48
48
48
48
49
49
49
50
8Concept of the HM8112-3
8.1Reference
8.2 Integrated AD converters
51
51
51
8.3
8.4
Moving average
Measurement of alternating values
51
51
9Introduction to the operation of the HM8112-3
51
10Control elements and displays
10.1 General functions
10.2 Buttons for the various measurement functions
10.3 Continuity test
10.4 Max / Min values
10.5 Range selection
10.6 Menu structure / Menu prompting
10.7 Menu structure and function
10.8 Measurement inputs
10.9 Replacement of the measuring circuit fuse
10.10 Rear Panel
52
52
52
54
54
54
55
55
58
59
59
11Scanner Card HO112
59
12Remote Operation
60
13
Data communication
13.1 Layout of commands
13.2 Command reference
60
60
60
14Listing of commands 63
Subject to change without notice
35
H M 8 1 1 2 - 3 HM8112-3
6½-Digit Precision Multimeter
HM8112-3 [HM8112-3S]
HM8112-3S:
Multimeter with built-in
Scanner Card (8+1
Channels, 2- and 4-Wire)
HZ42
19" Rackmount Kit 2RU
R
R
R
R
R
R
R
R
R
Precise Temperature
Measurement with Sensor
R
R
R
R
36
Subject to change without notice
6½-DigitDisplay(1,200,000Counts)
Resolution:100nV,100pA,100µΩ,0.01°C/F
DCBasicAccuracy0.003%
2-Wire/4-WireMeasurements
MeasurementIntervalsadjustablefrom0.1…60s
Upto100MeasurementsperSecondtransmittedtoaPC
TrueRMSMeasurement,ACandDC+AC
MathematicFunctions:LimitTesting,Minimum/Maximum,
AverageandOffset
TemperatureMeasurementswithPlatinum(PT100/PT1000)
andNi(KandJtypes)Sensors
InternalDataLoggerforupto32,000MeasurementResults
OffsetCorrection
GalvanicallyisolatedUSB/RS-232Dual-Interface,
6½-Digit Precision-Multimeter HM8112-3
optionalIEEE-488(GPIB)
[HM8112-3S]:HM8112-3incl.ScannerCard
(8+1Channelseach2-and4-Wire)
S p e c i f i c a t i o n s
6½-Digit Precision Multimeter
HM8112-3 [HM8112-3S]
Accuracy Values given are in ±(% of reading + % of full scale):
Range
100 Ω
1 kΩ
10 kΩ
100 kΩ
1 MΩ
10 MΩ
All data valid at 23 °C after 30 minutes warm-up.
DC specifications
Ranges HM8112-3:
0.1 V; 1 V; 10 V; 100 V; 600 V
Ranges HM8112-3S:
0.1 V; 1 V; 10 V; 100 V
Input impedance:
0.1 V, 1.0 V
>1 GΩ
10 V, 100 V, 600 V
10 MΩ
Accuracy Values given are in ±(% of reading (rdg.) + % of full scale (f.s.)):
1 year;
Range
% rdg.
0.1 V
0.005
1.0 V
0.003
10.0 V
0.003
100.0 V
0.003
600.0 V
0.004
Integration time:
Display range:
600 V range
Resolution:
Zero point:
Temperature drift
Long-term stability
AC specifications
Ranges HM8112-3:
Ranges HM8112-3S:
Measurement method:
23 °C ±2 °C
% f.s.
0.0006
0.0006
0.0006
0.0006
0.0006
0.1 s
120.000 digit
60.000 digit
1 µV
Temp. coefficient
10…21 °C + 25…40 °C
0.0008
0.0008
0.0008
0.0008
0.0008
1…60 s
1,200.000 digit
600.000 digit
100 nV
better than 0.3 µV/°C
better than 3 µV for 90 days
0.1 V; 1 V; 10 V; 100 V; 600 V
0.1 V; 1 V; 10 V; 100 V
true rms, DC or AC coupled
(not in 0.1 V range)
Input impedance:
0.1 V, 1 V
1 GΩ II <60 pF
10…600 V
10 MΩ II <60 pF
Response time:
1.5 sec to within 0.1 % of reading
Accuracy:
For sine wave signals >5 % of full scale
Values given are in ±(% of reading + % of full scale); 23 °C ±2 °C for 1 year
Range 20 Hz…1 kHz 1…10 kHz 10…50 kHz 50…100 kHz 100…300 kHz
0.1 V
0.1+0.08 5+0.5 (5 kHz)
1.0 V
0.08+0.08
0.15+0.08
0.3+0.1
0.8+0.15
7+0.15
10.0 V
0.08+0.08
0.1+0.08
0.3+0.1
0.8+0.15
4+0.15
100.0 V
0.08+0.08
0.1+0.08
0.3+0.1
0.8+0.15
600.0 V
0.08+0.08
0.1+0.08
Temperature coefficient 10…21 °C and 25…40 °C; (% rdg. + % f.s.)
at 20 Hz…10 kHz
0.01 + 0.008
at 10…100 kHz
0.08 + 0.01
Crest factor:
7:1 (max. 5x range)
Integration time:
0.1s1…60s
Display range:
120.000 digit
1,200.000 digit
600 V range
600.00 digit
600.000 digit
Resolution:
1 µV
100 nV
Overload protection (V/Ω-HI to V/Ω-LO) and to chassis:
Measurement ranges:
all
all the time:
850 Vpeak or 600 Vdc
Maximum input voltage LOW against chassis/safety earth:
250 Vrms at max. 60 Hz or 250 Vdc
Current specifications
Ranges:
Integration time:
Display ranges:
1 A range
Resolution:
Accuracy:
(1 year; 23 °C ±2 °C)
Temperature coefficient/°C:
(%rdg. + %f.s.)
Voltage:
Specifications
Response time:
Crest factor:
Input protection:
100 µA; 1 mA; 10 mA; 100 mA; 1 A
0.1 s
1…60 s
120.000 digit
1,200.000 digit
100.000 digit
1,000.000 digit
1 nA
100pA
DC
45 Hz…1 kHz
1…5 kHz
0.02 + 0.002 0.1 + 0.08
0.2 + 0.08
10…21 °C
25…40 °C
0.002+ 0.001
0.01+ 0.01
<600 mV…1.5 V
1.5 s to within 0.1 % of reading
7:1 (max. 5 x range)
fuse, FF 1 A 250 V
Resistance
Ranges:
Integration time:
Display ranges:
Resolution:
100 Ω, 1 kΩ, 10 kΩ, 100 kΩ, 1 MΩ, 10 MΩ
0.1 s
1…60 s
120.000 digit
1,200.000 digit
1 mΩ
100 µΩ
1 year;
%rdg
0.005
0.005
0.005
0.005
0.05
0.5
23 °C ±2 °C
%f.s.
0.0015
0.001
0.001
0.001
0.002
0.02
Temp. coefficient/°C
10…21 °C
25…40 °C
0.0008
0.0008
0.0008
0.0008
0.0008
0.0008
0.0008
0.0008
0.002
0.002
0.01
0.01
Measurement current:
Range
100 Ω, 1 kΩ
10 kΩ
100 kΩ
1 MΩ
10 MΩ
Max. measurement voltage: approx. 3 V
Overload protection:
250 Vp
Current
1 mA
100 µA
10 µA
1 µA
100 nA
Temperature measurement
PT100/PT1,000 (EN60751): 2- and 4-wire measurement
Range
-200…+800 °C
Resolution
0.01 °C; measurement current 1 mA
Accuracy
±(0.05 °C + sensor tolerance + 0.08 K)
Temperature coefficient
<0.0018 °C/°C
10…21 °C and 25…40 °C
NiCr-Ni (K-type):
Range
-270…+1,372 °C
Resolution
0.1 °C
Accuracy
±(0.7 % rdg. + 0.3 K)
NiCr-Ni (J-type):
Range
-210…+1,200 °C
Resolution
0.1 °C
Accuracy
±(0.7 % rdg. + 0.3 K)
Frequency and period specifications
Range:
1 Hz…100 kHz
Resolution:
0.00001…1 Hz
Accuracy:
0.05 % of reading
Measurement time:
1…2 s
Specification Scanner Card HO112: refer to page 59
Interface
Interface:
Functions:
Inputs:
Outputs:
Miscellaneous
Time to change range or
function:
Memory:
Safety class:
Power supply:
Power consumption:
Operating temperature:
Storage temperature:
Rel. humidity:
Dimensions (W x H x D):
Weight:
*)
Dual-Interface USB/RS-232 (HO820),
IEEE-488 (GPIB) (optional)
Control / Data fetch
Function, range, integration time, start
command
Measurement results, function, range,
integration time (10 ms…60 s)
approx. 125 ms with DC voltage, DC current,
resistance approx. 1 s with AC voltage,
AC current
30,000 readings /128 kB
Safety class I (EN 61010-1)
105…254 V~; 50…60 Hz, CAT II
approx. 8 W
+5…+40 °C
-20…+70 °C
5…80 % (non condensing)
285 x 75 x 365 mm
approx. 3 kg
max. 1 μV after a warm-up of 1.5 h
at rel. humidity <60 %
**)
Accessories supplied: Line cord, Operating manual, PVC test lead (HZ15),
Interface cable (HZ14), CD
Recommended accessories:
HO112 Scanner Card (Installation only ex factory) as HM8112-3S
HO880 Interface IEEE-488 (GPIB), galvanically isolated
HZ10S 5 x silicone test lead (measurement connection in black)
HZ10R 5 x silicone test lead (measurement connection in red)
HZ10B 5 x silicone test lead (measurement connection in blue)
HZ13 Interface cable (USB) 1.8 m
HZ33
Test cable 50 Ω, BNC/BNC, 0.5 m
HZ34
Test cable 50 Ω, BNC/BNC, 1.0 m
HZ42 19" Rackmount kit 2RU
HZ72
GPIB-Cable 2 m
HZ887 Temperature probe
Subject to change without notice
37
I m p o r t a n t h i n t s 1.4Transport
1Important hints
Please keep the carton in case the instrument may require later
shipment for repair. Losses and damages during transport as
a result of improper packaging are excluded from warranty!
1.5Storage
HINT
(1)
(2)
(3)
(4)
(5)
(6)
Dry indoor storage is required. After exposure to extreme temperatures, wait 2 hrs before turning the instrument on.
1.1Symbols
1.6Safety instructions
Symbol 1:
Symbol 2:
Symbol 3:
Symbol 4:
Symbol 5:
Symbol 6:
The instrument conforms to VDE 0411/1 safety standards applicable to measuring instruments and it left the factory in proper
condition according to this standard. Hence it conforms also
to the European standard EN 61010-1 resp. to the international standard IEC 61010-1. Please observe all warnings in this
manual in order to preserve safety and guarantee operation
without any danger to the operator. According to safety class 1
requirements all parts of the housing and the chassis are connected to the safety ground terminal of the power connector.
For safety reasons the instrument must only be operated from
3 terminal power connectors or via isolation transformers. In
case of doubt the power connector should be checked according
to DIN VDE 0100/610.
Attention, please consult manual
Danger! High voltage!
Ground connection
Important note
Hints for application
Stop! Possible instrument damage!
1.2Unpacking
Please check for completeness of parts while unpacking. Also
check for any mechanical damage or loose parts. In case of
transport damage inform the supplier immediately and do not
operate the instrument.
Do not disconnect the safety ground either inside or
outside of the instrument!
1.3Positioning
Two positions are possible: According to picture 1 the front
feet are used to lift the instrument so its front points slightly
upward. (Appr. 10 degrees)
If the feet are not used (picture 2) the instrument can be combined with many other Hameg instruments.
In case several instruments are stacked (picture 3) the feet rest
in the recesses of the instrument below so the instru-ments
can not be inadvertently moved. Please do not stack more than
3 instruments. A higher stack will become unstable, also heat
dissipation may be impaired.
picture 1
picture 2
– The line voltage of the instrument must correspond to the
line voltage used.
– Opening of the instrument is only allowed to qualified personnel
– Prior to opening, the instrument must be disconnected from
the line voltage and all other inputs/outputs.
In any of the following cases the instrument must be taken out
of service and locked away from unauthorized use:
–
–
–
–
–
–
Visible damage
Damage to the power cord
Damage to the fuse holder
Loose parts
No operation
After long term storage in an inappropriate environment,
e.g. open air or high humidity.
– Excessive transport stress
1.7CAT II
The following remarks concern only the safety of the user. Other
aspects e.g. the maximum input voltage etc. are covered in the
specifications section of this manual and are to be observed
as well.
picture 3
Measurements in circuits which are indirectly connected with
the mains supply are possible with adequate converters (e.g.
clamp-on ammeters) which fulfil at least the requirements
of the safety class of the measurement. The measurement
category of the converter specified by the manufacturer must
be considered.
Measurement categories CAT
The measurement categories were created with respect to the
different kind of transients incurred in practice. Transients are
38
Subject to change without notice
I m p o r t a n t h i n t s
Only valid in EU countries
In order to speed reclamations customers in EU countries may
also contact HAMEG directly. Also, after the warranty expired,
the HAMEG service will be at your disposal for any repairs.
Overhead lines
Premises
In-house
installation
CAT IV
Permanently installed
machinery, distribution sites,
power conductors, mains
outlets close to the CAT IV
installation
CAT III
Mains outlets for
household appliances,
portable tools, PC,
refrigerator etc.
CAT II
short, fast, and fast-rise changes of voltage or current, and
may be periodic or non-periodic. The amplitude of transients
increases with decreasing distance from their source.
CAT IV: Measurements at the source of a low voltage supply,
e.g. at electricity meters.
CAT III: Measurements inside a building, e.g. at distribution
sites, power switches, permanently installed mains
outlets, permanently mounted motors etc.
CAT II: Measurements in circuits which are directly connected
with the low voltage supply, e.g. household appliances,
portable tools etc.
CAT I: Electronic instruments and circuits which contain
circuit breakers resp. fuses.
Return material authorization (RMA):
Prior to returning an instrument to HAMEG ask for a RMA
number either by internet (http://www.hameg.com) or fax. If
you do not have an original shipping carton, you may obtain one
by calling the HAMEG service dept (+49 (0) 6182 800 500) or by
sending an email to [email protected]
1.10Maintenance
Before cleaning please make sure the instrument
is switched off and disconnected from all power
supplies.
Clean the outer case using a dust brush or a soft, lint-free dust
cloth at regular intervals.
No part of the instrument should be cleaned by the
use of cleaning agents (as f.e. alcohol) as they may
adversely affect the labeling, the plastic or lacquered surfaces.
The display can be cleaned using water or a glass cleaner (but
not with alcohol or other cleaning agents). Thereafter wipe the
surfaces with a dry cloth. No fluid may enter the instrument.
Do not use other cleaning agents as they may adversely affect
the labels, plastic or lacquered surfaces.
1.8 Proper operating conditions
1.11Mains voltage
Operation in the following environments: industry, business and
living quarters, small industry. The instruments are intended
for operation in dry, clean environments. They must not be operated in the presence of excessive dust, humidity, nor chemical
vapours in case of danger of explosion.
A main voltage of 115 V and 230 V can be chosen. Please check
whether the mains voltage used corresponds with the voltage
indicated by the mains voltage selector on the rear panel. If not,
the voltage has to be changed.
The maximum permissible ambient temperature during operation is +5 °C to +40 °C. In storage or during transport the
temperature limits are: –20 °C to +70 °C. In case of exposure to
low temperature or if condensation is suspected, the instrument
must be left to stabilize for at least 2 hrs prior to operation.
1.12Line fuse
In principle the instrument may be used in any position, however
sufficient ventilation must be ensured. Operation for extended
periods of time requires the horizontal or tilted (handle) position.
Nominal specifications are valid after 30 minutes warm-up at
23 deg. C. Specifications without tolerances are typical values
taken of average production units.
1.9 Warranty and Repair
HAMEG instruments are subjected to a rigorous quality control.
Prior to shipment each instrument will be burnt in for 10 hours.
Intermittent operation will produce nearly all early failures.
After burn in, a final functional and quality test is performed to
check all operating modes and fulfilment of specifications. The
latter is performed with test equipment traceable to national
measurement standards.
Statutory warranty regulations apply in the country where the
HAMEG product was purchased. In case of complaints please
contact the dealer who supplied your HAMEG product.
The instrument has 2 internal line fuses: T
0.2 A. In case of a blown fuse the instrument
has to be sent in for repair. A change of the
line fuse by the customer is not permitted.
1.13 Power switch
Normally the power switch on the rear panel of the instrument
should be stay in “ON“ position. If using the Standby-button on
the front panel, only the controls and the display are turned off.
The instrument itselfs stays turned on as long as it is connected
to the supply voltage. This has the advantage that the instrument
is immediately functional after turn-on. Also the reference
voltage source will remain energized, so any drift after turn-on
will be eliminated, also its long term drift will be substantially
improved. To switch-off the instrument completely, the power
switch on the back panel has to be operated.
If the instrument is left unattended for some time, the power
switch on the rear panel has to be operated. (Because of safety
reasons!)
Subject to change without notice
39
C o n t r o l e l e m e n t s 2
3 4
5
27
1
6
7
8
9
10 11
12 13
14 15
16 17
19 20
18 21
22 23
24
25
26
17 MIN – min. value during a test series
2Control elements
1 Display – 16 digit display
2 POWER – Stand by / ON
18 MENU – Call of the menu, acceptance of values entered
19 ESC – Leaving the menu without acceptance of the values
entered
3 HOLD DISPLAY – storage of the displayed value
4 ZERO – 0-compensation of the measuring section
5 RM/LOCAL-pushbutton – Return to manual mode
6 VDC – Measurement of DC voltage
20 – down: Switching to a higher range and scrolling down
the menu
21 AUTO – Activation/Deactivation of the auto range function
22 ENTER – Special function: Parameter selection in the logger
menu
7 ADC – Measurement of DC current
23 8 VAC – Measurement of AC voltage with AC coupling
24 V SENSE – Input for measurements of voltage, frequency,
resistance, temperature
9 A AC – Measurement of AC current
10 VAC+DC – Measurement of AC voltage with DC coupling
11 Ω – Measurement of resistance, 2- and 4-wire
12 FREQ./PERIOD – Frequency and period measurement with
– up: Switching to a lower range and scrolling up the menu
25 LO – Ground connection for inputs 24 and 26
26 A SOURCE – Input for current measurement
27 FUSE – 1 A / 250 V (FF) Measuring circuit fuse
VAC
13 δPT – Measurement of temperature using a PT-sensor,
Rear panel
14 28 Power receptacle with power switch
2- and 4-wire
– Diode test / Continuity test
15 δTH – Measurement of temperature using a thermocouple,
2-wire
16 MAX – max. value during a test series
29
40
Subject to change without notice
29 USB/RS-232 Interface
Option: HO880 IEEE-488 (GPIB); installed Scanner Card in
the HM8112-3
30 Voltage selector (115 V / 230 V)
28
30
M e a s u r e m e n t P r i n c i p l e s a n d B a s i c s
3Measurement Principles and Basics
What does „measure“ mean:
The reproducible comparison of an unknown with a known
reference and the display of the result as a multiple of the
unit of the reference.
3.1 Display of measuring ranges
There are various methods to describe the display of a multimeter. The simplest one consists of just specifying the number
of available digits. The measuring range of a Digital Multimeter,
in short DMM, thus indicates how many steps the display can
show. Some examples will be the best method to describe the
definition of the range of display.
Measuring result 1:
1 0 V
10V
Display 1:
1 0,0 0 0 0 0
1 0,0 0 0 0 0
Measuring result 2:
1 2,5 0 0 0 0 V
1 2,5 0 0 0 0 V
Display 2:
1 2,5 0 0 0 0
1 2,5 0 0 0 0
Measuring result 3:
1 2,6 0 0 0 0 V
1 2,6 0 0 0 0 V
Display 3:
1 2,6 0 0 0 0
1 2,6 0 0 0
DMM no. 1 with 2,000,000 digits is able to display up to 1,999,999,
the DMM no. 2 with 1,250,001 digits can only display up to
1,250,000. .DMM no. 1 is hence specified with an „overrange
of 100 %“. In contrast DMM no. 2 has an overrange of 25 %. If
DMM no. 2 had a range of display of 1,400,000 digits, it would
have an overrange of 40 %.
The measuring range of a DMM thus is given by the
full range minus overrange.
A 6-digit, a 6½-digit and a 6¾-digit DMM will be used for the
explanation.
6-digit DMM
6½-digit DMM
6¾-digit DMM
0 0 0 0 0 0
0 0 0 0 0 0 0
0000000
Range
of the display:
to toto
Change of decades
HINT
Example: 6½-digit DMM with 1,250,001 digits:
Full range:
– Overrange:
Measurement range:
12,50000 V
2,50000 V
10,00000 V
9 9 9 9 9 9
1999999
3999999
3.3Resolution of a measuring range
1.0 0 0.0 0 0 digit
2.0 0 0.0 0 0 digit
4.0 0 0.0 0 0 digit
The resolution of a digital measuring instrument is equal to the
least significant digit of the display. The digitized measurement
value is hence quantized. In contrast to this, the resolution of an
analog measuring instrument is given by the smallest change
discernible by the viewer. With analog measurement each
measurement value corresponds to a unique display.
Availabe number
of digits:
The „6“ indicates the number of digits which are always shown in
the display. The fraction ½ resp. ¾ indicates at which number in
the highest digit the range will be switched to the next (change
of decades). The switchover to the next higher range will cause
a loss of one digit in the display, hence also the resolution will
be reduced by one digit.
In the following an example will be given for the switching of
the number of digits of the display when the range is switched.:
Measuring result 1: 1 0 V
1 0 V
10V
Display 1:
1 0,0 0 0 0 0
1 0,0 0 0 0 0
Measuring result 2: 2 0 V
1 0,0 0 0
2 0 V
20V
Display 2:
2 0,0 0 0 0
2 0,0 0 0 0 0
2 0,0 0 0
Change of decades
Measuring result 3: 3 9,9 9 9 9 9 V
3 9,9 9 9 9 9 V
3 9,9 9 9 9 9 V
Display 3:
3 9,9 9 9 9
3 9,9 9 9 9 9
Measuring result 4: 4 0 V
3 9,9 9 9
4 0V
40V
Display 4:
4 0,0 0 0 0
4 0,0 0 0 0
4 0,0 0 0
Change of decades
The display of the measurement range of 6½ digits
is only possible at a measuring time of 60s.
The resolution of a DMM depends on the number
of available digits and is the reciprocal value of the
number of digits (without the overrange).
HINT Example: 6½-digit DMM with 1.2 0 0.0 0 0 digit
The overrange amounts to 200,000 digits, hence the
resolution follows:
1
= 0,000001
1.200.000 – 200.000
this is equivalent to 0.0001 % of full range.
A DMM has a resolution of 0.1 V in the 100 V range. If a voltage
of 100.05 V is to be measured, the DMM can display either 100.0
V or 100.1 V (disregarding all other measurement uncertainties). The DMM can never measure more accurately than the
resolution allows which is here 0.1 %.
3.2Overranging
3.4Measurement accuracy
In the previous example our 6½ – digit DMM had a range of the
display of 2,000,000 digits. The switching of decades took place
when in the first digit the number 1 changed to 2. Another 6½ –
digit DMM may have a range of display of 1,250,001 digits. Here,
the switching of decades also happens in the highest digit, but
whenever the 3rd digit changes from 5 to 6.
The measurement accuracy of a digital measuring instrument
is by its nature principally limited by its resolution. The theoretical maximum accuracy of a measurement and also the least
significant display digit are defined by the smallest quantizing
step (LSB = least sigificant bit) of the analog/digital converter.
6½-digits DMM1
6½-digits DMM2
Display range:
0 0 0 0 0 0 0
0000000
to
to
1999999
1250000
Measuring points:
2.0 0 0.0 0 0 digit
1.2 5 0 0 0 1 digit
The following factors influence the accuracy of a DMM:
– Active and passive component tolerances and their temperature dependence
– Stability of the reference voltage of the DMM
– Properties of the a/d converter
Subject to change without notice
41
M e a s u r e m e n t P r i n c i p l e s a n d B a s i c s Z(Vin)
Z(Vin)
Ideal function of
the a/d converter
Ideal function of
the a/d converter
0110
0110
0101
0101
0100
The slope of the function of the
a/d converter is affected by
amplification error
0100
Function of the a/d converter
is displaced by offset error
0011
0010
0011
0010
0001
0001
V in
Ue
V in
Fig. 2: A/D converter amplification error
Z(Vin)
Z(Vin)
0110
Ideal function of
the a/d converter
(linear)
0110
Ideal function of
the a/d converter
(linear)
0101
0101
Actual from
interval Vin
at 0110
0100
Ideal from interval Vin at 0110
0011
0001
0100
0011
0010
0010
Nonlinearity of the
a/d converter
Max. deviation of the nonlinear
slope curve of the a/d converter
to the ideal linear function
0001
Nonlinearity of the
a/d converter
Vin
V in
Fig. 4: A/D converter integral nonlinearity
Fig. 3: A/D converter differential nonlinearity
Offset errors of the A/D converter
The input amplifier of the DMM is not properly adjusted and
shows an offset. This offset causes an offset error in the a/d
conversion. (Fig. 1)
Slope error (amplification factor error) of the A/D converter
The input amplifier’s amplification factor is temperaturedependent, or the amplification factor was maladjusted. Hence
the slope of the function differs from the ideal value. (Fig. 2).
Differential nonlinearity of the A/D converter
The quantizing steps of the a/d converter are unequal in size
and differ from the ideal theoretical value. The differential
nonlinearity indicates how much each voltage interval (actual)
differs from the ideal voltage interval (ideal, 1 LSB)) ΔVin (Fig.
3) when the analog voltage Vin is being converted.
Differential linearity error = k x ΔVin; k= factor, describing the relationship ΔVin (actual) to ΔVin (ideal)
42
Subject to change without notice
Linearity error (integral nonlinearity) of the A/D converter
Due to the individual differential linearity errors and their sum
a maximum error between the ideal conversion characteristic
and the actual one will accrue. The linearity error specifies the
maximum distance between the two functions (Fig. 4).
A/D conversion methods
In the following, the Single Slope, the Dual Slope and the Multiple Slope methods will be described. These sawtooth converters
are based on the same principle: conversion of the input voltage
into a proportional time span.
Name: Single Slope
M e a s u r e m e n t P r i n c i p l e s a n d B a s i c s
3.5Single-Slope A/D conversion
input voltage will yield a lower slope and a lower ramp voltage
(see Vr2). As the reference voltage which is connected to the
integrator at t2 is constant, the downward slope is constant,
hence the time for disharging the integration capacitor differs.
It takes more time to discharge the higer ramp voltage Vr1 than
for discharging the smaller ramp voltage Vr2. The input voltage
Vin can thus be determined from the respective discharge time
span Δt2 = t3 – t2 and the constant reference voltage.
V
Vin = Vref
r
V
Advantages:
The accuracy is no longer dependent on the accuracy of the RC
of the integrator, nor on the counter frequency. all 3 must only
be constant during a complete cycle Δt1 + Δt2. If their values
change over time, this will only affect the slopes of both ramps.
If the slope of the upward ramp becomes higher, a higher ramp
voltage Vr will be reached. But the downward slope will also be
steeper such that the ramp will cross 0 V at the same point in
time t3 as before.
0V
t1
t
t2
Vr
Fig. 5: Single-Slope
The simplest method is the single slope conversion. A sawtooth
is generated by integrating a reference voltage Vref. There are
two comparators, one compares the ramp with 0 V, the second
with the unknown input voltage Vin. As soon as the ramp crosses 0 V, a counter is started which is stopped when the second
comparator switches at Vin. The accumulated count is proportional to the input voltage Vin. The disadvantage is the limited
accuracy as it is directly affected by R and C of the integrator.
t1 = const.
*
V r1
t2
V r1
0V
t
t3
3.6 Dual-Slope A/D conversion
t1
t2
t3
Vr
t1 = const.
V r1
Fig. 7: Dual Slope: Change of time constant by component drift
t2
As this type of converter does not measure the instantaneous
value of the input voltage but its average during the upintegration time Δt1, high frequency ac voltages are attenuated. If the
frequency of the superimposed ac voltage is equal to 1/Δt1 or a
multiple thereof, this frequency will be completely suppressed.
If Δt1 is made equal to the line frequency or multiples thereof,
hum interference will be rejected.
V r2
0V
t
t3
t1
t2
t3
Fig. 6: Dual-Slope principle
With the dual slope method the accuracy is not dependent
on R and C of the integrator, both and the counter frequency
must only be constant during a complete conversion cycle. The
measurement starts at time t1: a counter is started while the
input voltage Vin is integrated. The integration stops when the
counter reaches its maximum count, the integration time Δt1
is thus constant, the input voltage is disconnected from the
integrator. Now the reference voltage Vref which is of opposite
polarity is connected to the integrator. At time t2 the counter
starts to count again. The ramp changes its polarity and runs
towards 0 V. The counter stops at t3 when the ramp reaches 0 V.
The time span Δt2 = t3 – t2 is proportional to the input voltage.
If the input voltage was high, a higher ramp potential will result at the end of Δt1 as if the input voltage was small. A small
3.7Multi-Slope A/D conversion
The Multiple Slope method is based on the Dual Slope method.
Several measurements are performed with the Dual Slope
method, their results are averaged. This calculated value wil
Vr
#Vidt
#Vrefdt
V r1
V r1
0V
t
t0
Phase 1
t1
Phase 2
t2
Phase 3
4 5
Phase 1
t3 t4 t5/0
t1
Fig. 8: Multi-Slope
Subject to change without notice
43
M e a s u r e m e n t P r i n c i p l e s a n d B a s i c s then be displayed. The number of measurements for averaging
decides how well interference will be suppressed. Because the
input voltage is continuously being integrated upwards and
then the reference voltage downwards, three further steps are
necessary. In the following the individual steps for converting
one measurement value are described. For averaging a number
of measurement results is required.
Phase 1: Autozero – constant time span Δt1
The duration of the autozero phase is, in general, identical to
the integration time of the input voltage Vin. This is to ensure
that all errors to be expected will be caught. The errors caused
by the offsets of the comparators and the integrator will be
compensated by adding a definite offset (which is mostly stored
on a separate capacitor).
Phase 2: Integration of the input voltage Vin
Constant time span Δt1.
Phase 3: Integration of the reference voltage Vref
Δt2 depends on the amplitude of the ramp voltage Vr at time t2.
The duration of this time span must be measured with great
accuracy, because the digital value of the input voltage will be
determined from this time span.
Phase 4: Overshoot Δt3
Due to delays in the integrator and the control signals (e.g. by
a microcontroller) an overshoot is generated. The integrator
capacitor charges in negative direction. This charge is eliminated in phase 5.
Phase 5: Integrator Output Zero Δt4
The charge caused by the integrator overshoot will be
discharged.
3.8 Accuracy specifications
The accuracy specifications of multimeters consist of diverse
numbers and units.
The measurement deviation is specified as:
± (xx % of measurement + xx % of range) at a temperature
of xx °C ± xx % ; this will apply for a time span of (xx hours, xx
days, xx years)
Example: Measuring range 10 V:
± (0.004% of rdg + 0,001% of f.s.) valid for 24 h at 23 ±1 °C
The temperature coefficient specifies the deviation per degree
C valid in a specified temperature range.
Example: Measuring range 10 V:
± (0.001% of rdg /°C) within a temperature range of (10 ... 21°C).
The long term stability indicates the irreversible drift of the
instrument for a given time span. Standard time intervals are:
30 days, 90 days, 1 year, 2 years.
Example: Long term stability better than 3µV for 90 days at
23 ±2 °C.
The short term stability indicates how far a measuring instrument is useful for comparative measurements with other
measuring instruments. This is valid for a short time span within
a limited temperature range.
Example: Short term stability better than 0.02 µV within 24 h
at 23 ±1 °C.
44
Subject to change without notice
To be calculated:
The possible total deviation at 16 °C in the 10 V
range.within a time span of 14 hrs. The measureHINT ment result shown is 6.000000 V?
Calculation:
± (0.004% of 6.0 V + 0.001% of 10 V)
for 24h at 23 ±1 °
Result: 0.00034 V.
± (0.001% of 6.0 V / °C) x ΔT
within a temperature range of (10 ... 21 °C)
with ΔT = (23-1 °C) – 16 °C = 6 °C
Result: 0.00036 V
The possible total deviation is equal
to the sum and amounts to 0.00070 V.
D C m e a s u r e m e n t s
4 DC measurements
4.1Input resistance for dc measurements
In order to profit from the high linearity of the conversion method, the input resistance is extremely high for input voltages
up to 1 V (> 1 GΩ). In this range, the instrument still allows precise measurements with a maximum of 1 ppm load error with
measuring objects with an internal resistance of 1 kΩ.
In the ranges 10 V, 100 V, 1000 V an internal resistance of 100 Ω, with 100,000 digits resolution, will
HINT already cause an error of one digit.
The values of the input resistance and the maximum number of
available digits in the various ranges are given in the following
table; the maximum number of digits is valid with an integration
time of 1 or 10s.
Range
MaximumMaximum
number of inputMaximum
digits
resistanceresolution
100 mV
1 V
10 V
100 V 600 V The influence of the source resistance is shown in the following
figure.
Rs
is achieved. Due to the integration the positive and negative
portions of the hum from the line will cancel. The interference
from the line thus can be almost completely eliminated. The
Multifunctionmeter HM8112-3 achieves a series mode rejection
of > 100 dB for 50/60 Hz ± 5 %.
4.3Common mode rejection
Common mode rejection is the ability of a measuring instrument
to only display the desired difference signal between the „HI“ and
„LO“ input terminals while suppressing any signals referenced
to to ground common to both input terminals as far as possible.
In an ideal system there would be no error; in practice stray
capacitances, isolation resistances and ohmic unsymmetries
convert part the common mode signal to series mode.
4.4Thermal voltages
One of the most frequent causes of dc measurement errors
at low levels are thermoelectric voltages. They are generated
at the contact junctions between two different metals which
are at the same temperature or differring temperatures. The
drawing shows the various points in a measurement circuit
which are possible sources of thermoelectric voltages; those
may be at an external contact junction (contact 1/2) but also
within the terminals of the measuring instrument. Hence it is
necessary to make sure that junctions are either made of the
same material or at least to use materials which generate only
very small thermoelectric voltages when brought in contact.
contact 1
at T1
DMM
Material 1
Material 2
Vs
Vs
Ri
V Vm
V
Material 1
contact 2
at T2
Ri =
Rs =
Vs =
Max. Input resistance of the DMM
(10 MΩ oder >1 GΩ)
Source resistance of the measurement object
Voltage of the measurement object
The error in % of a measurement comes about as follows:
100 x Rs
Error (%) = ——————
Rs + Ri
Example:
Ri ≥1 GΩ; Rs = 10 kΩ,
measurement error = 0,001% (10 ppm)
The often used unit ppm for errors can be calcula-
HINT ted: error in (%) x 10,000.
4.2Series mode rejection
One of the main advantages of an integrating measuring method is the high series mode rejection of ac components (e.g.
interference from the line) which are superimposed on the
signal voltage. For frequencies for which the integration time
is a multiple of their period theoretically an infinite suppression
DMM
contact 3
(HI connector)
Vm
Material 2
contact 4
(LO connector)
The table below shows the different thermoelectric voltages für
diverse material combinations.
Contact materialsThermoelectric voltage (appr.)
Cu - Cu
<0,3 µV/°C
Cu - Ag (Silver)
0,4 µV/°C
Cu - Au (Gold)
0,4 µV/°C
Cu - Sn (Tin)
2-4 µV/°C; depending on the composition
If, e.g. the material no. 1 is a silver conductor and
the material no. 2 a copper cable, a temperature
difference of only 1 degree will generate already a
thermoelectric voltage of 400 nV. This would cause
a ±40 digit error in the smallest range and 7½
digits resolution (10 nV sensitivity). For 6½ digits
of resolution the error would thus amount to ± 4
digits. With the HM8112-3, 6½ digits resolution ,
the influence of this level of thermoelectric voltage
HINT would affect the last digit.
Subject to change without notice
45
R e s i s t a n c e M e a s u r e m e n t 4.5 Interference by magnetic fields
5.2 Four-wire resistance measurement
If the measuring cables are in the vicinity of ac magnetic fields,
a series mode interference signal will be induced. Such a source
of interference may be a cable carrying high mains frequency
currents or a transformer. Twisted pairs of measuring cables
will minimize the pick-up of magnetic interference in the vicinity
of a magnetic field. Measuring cables should not float around
freely nor should they be moved during a measurement, because this may also cause erroneous measurements. A greater
distance to the interfering field or shielding are further means
to minimize interference.
In order to prevent the measuring problems caused by the cable
resistances, the 4-wire circuit is used for all small resistors. In
a 4-wire measurement circuit also a current from a precision
current source flows through the resistor R. The voltage drop
across R is taken off directly by two more cables and measured,
and this voltage drop is strictly proportional to the resistance
value only.
DMM
RL
R
5Resistance Measurement
5.1Two-wire resistance measurement
A current from a current generator flows through the DUT
and the measuring cables’ RL. The voltage drop across R is
measured. But there is also a small voltage drop across the
measuring cables. This is why it is necessary, especially when
measuring small resistances ( < 1 kΩ) to carefully compensate
for the measuring cables’ resistances and thermoelectric voltages by using the offset correction feature. This is performed by
connecting both measuring cables to one side od the DUT, i.e.
shorting them, then the button ZERO 4 should be pushed.
This eliminates the sources of error like cable resistance, contact resistance, and thermoelectric voltages at the junctions of
dissimilar metals.
If no offset correction was performed, a value for R will be displayed which consists of the sum of all resistances within the
measurement circuit, the result will hence be too high by the
amount of cable and other resistances.
RL
DMM
V
Um
Im
RL
In practice, usually cables of 1 m length are used which have
a resistance of 10 .. 20 mΩ. If the resistor to be measured is
100 Ω, this will cause an error of 0.04 %. With small resistances,
especially in the 100 Ω range, the cable resistance thus becomes remarkable. In these ranges 4-wire measurements are
recommended.
46
Subject to change without notice
RL1
V
Um
Im
RL
The HM8112-3 measures resistances by injecting currents,
2 and 4 wire circuits are possible. A current from a precision
current generator is sent through the resistor R, the voltage
drop is measured.
R
RL1
The „outer“ connections SOURCE of the 4-wire resistance
terminals are the ones which force the measuring current via
the cables with their resistances RL through the resistor to be
measured. The „inner“ measuring cables with their resistances
RL1 are connected to the V-SENSE- INPUT of the measuring
instrument which has a high input resistance, hence the voltage
drop across RL1 is neglegible.
In both the 2-wire and 4-wire circuits shielded cables
should be used for the measurement of large resistances (> 100 kΩ), the screen should be connected
to ground in order to prevent interference from
other voltage sources (like mains frequency hum).
The cables should also have a high insulation resistance (e.g. Teflon insulation), otherwise leakage
current problems could arise, caused by the parallel connection of the DUT, R, and the insulation
resistance.
It is also advantageous to select a longer integration time > 1s in order to suppress interference by
the longer integration of the measuring signal.
5.3 Power dissipation of the resistors
A source of error, often overlooked when measuring resistive
sensors (e.g. temperatur sensors), is the power dissipation in
the resistors to be measured and their ensuing self-heating.
Especially with sensors with a high temperature coefficient the
measuring result can be adversely affected. The influence of
this source of error can be reduced by proper range selection.
The following table lists the power dissipation at full scale in
the various ranges.
Range
Measuring current
Power dissipation
at full scale reading
100 Ω 1 mA
100 µW
1 kΩ 1 mA 1 mW
10 kΩ
100 µA
100 µW
100 kΩ 10 µA 10 µW
1 MΩ 1 µA 1 µW
10 MΩ 100 mA
100 mW
A C m e a s u r e m e n t s
û
û
0
t
û
0
IuI
0
0
t
t
tt
∫
∫
∫ ∫∫
∫
0
ππ
π ππ
pπ ——
——
——
1,11
1,11
== 1,11
——
== 1,11
——
22 =22 1,11
2
HINT 2 22
IuI
IuI
IuI IuI
IuI
000 00
0
t
tt
Crestfaktor
3.5
Crestfaktor
Crestfaktor
Crestfaktor
A C m e a s u r e m e n t s 6.6Crest factor
CrestForm
factorfactor
C F
Form factors
The crest factor is derived by dividing the peak value by the rms
value of a signal. It is very important for the correct measurement of pulse signals and a vital specification of a measuring
instrument.
2
p
= 1,11
2 2
2
p
= 1,11
2 2
û peak value
C
= ——=——————————
Vrms
rms value
For sinusoidal signals the crest factor is
HINT √2 = 1.414
If the maximum permissible crest factor of a measuring instrument is exceeded, the result will be
inaccurate because the measuring instrument will
be overdriven.
The accuracy of the rms calculation depends on the crest factor,
it deteriorates with increasing crest factor. The specification of
the maximum crest factor relates to the full scale value (see
specifications). If a range is not used up to full scale, the crest
factor may be higher (e.g. 230V measured in the 500V range.)
See figure form factors.
2
p
2
= 1,57
3
2
= 1,15
3
6.7 DC and AC currents
Current measurements are performed in the HM8112-3 by
using precision shunts. The voltage drop across the shunt is
measured. Due to the resistance of conductors and cables RL
a total load voltage VB accrues which may lead to false measurement results.
Rs
DMM
RL
7Temperature measurement
In the international SI system of units the Kelvin (K) was defined as the basic unit for temperature measurements. Degree
Centigrade (°C) is a lawful unit, derived from the SI units, and
internationally accepted. In the USA, temperatures are still
mostly given in degrees Fahrenheit (°F).
Vs
R
V
Absolute temperatures are mostly in degrees Centigrade (°C). Relative temperatures or temperature
HINT differences are given in Kelvin (K).
Kelvin (K)
Fig.: Principle of the current measurement using shunts
VS = Source voltage
RS = resistance of the source
VB = Burden voltage R = Shunt inside the multimeter
RL = Resistance of conductors and cables
The measurement error in % follows from:
Error (%) = 100 x VB
—————–
VS
Centigrade (°C)
0 K
255,38 K
273,15 K
373,15 K
Conversion table:
°C to K: T[K] =
°K to °C: T[°C] =
°C to °F: T[°F] =
°F to °C: T[°C] =
-273,15 °C
-17,77 °C 0 °C
100 °C
T[°C] +273,15 K
T[K] –273,15 K
9/5 x (T[°C] +32 °F
5/9 x (T[°F] –32 °F)
Abbreviations and symbols:
T[K] temperature given in [K]
T[°C] temperature given in degrees Centigrade [°C]
T[°F] temperature given in degrees Fahrenheit [°F]
7.1Temperature sensors
The temperature sensors used most are the NiCr – Ni thermocouple (K-type) and the platinum sensor PT100. The characteristics of the temperature sensors are defined in the norms
only for a limited range. Outside this range there are no reliable
values. If the measuring range of the temperature sensors is
exceeded, the HM8112-3 hence indicates „Overrange“.
48
Subject to change without notice
T e m p e r a t u r e m e a s u r e m e n t
7.2 Platinum temperature sensor PT100
The platinum temperature sensor PT 100 is a resistance sensor.
Due to the stability of the resistance over time and because it
stands up well against aggressive media, platinum is a good resistive material for temperature sensors. A change in temperature causes a change in the resistance. The nominal value R0 is:
R0 = 100 Ω at T0 = 0 °C
The temperature range for the PT100 extends from –200 °C
bis +850 °C.
There are more PT resistance sensors like PT10,
PT25, PT500, PT1000. The nominal resistance
values at To = 0 °C are here: 10, 25, 500 and 1000 Ω
respectively. The types PT10, PT25, PT500 can not
HINT be used with the HM8112-3.
7.3Temperature measurement with the PT100 /
PT1000
Measurement voltage with Imeas ≅ 0
FUSE
1A
F250V
max. INPUT
600V rms / 1A rms
V
A
Measurement current IPT100 = const
SENSE
HI
max. max.
850 850
Vpk Vpk
Ω,ϑ
PT100
LO
max.
250Vrms
CAT II
The most used and most accurate method of temperature
measurement is in a 4-wire circuit. From the SOURCE 26 terminals of the measuring instrument a constant current flows
to the PT100. The change of PT100 resistance depends on the
change of temperature at the PT100. A change of temperature
also causes a change of the resistance of the connecting cables
RL. As the measuring voltage is directly taken from the PT100
and applied to SENSE 24 , and because the input resistance of
the input amplifier is very high, a neglegible current will flow in
the SENSE cables (Imeas appr. 0). Hence the voltage drop across
the SENSE cables caused by the current in them does not (or
only to a neglegible extent) influence the measurement. Also
any change of resistance RL in the SENSE cables has hardly any
influence. As the measuring voltage is taken from the PT100
at the ends of the SOURCE cables, only the resistance of the
PT100 is measured. Any change of resistance of the SOURCE
cables has no influence on the measurement.
FUSE
1A
F250V
max. INPUT
600V rms / 1A rms
V
7.4NiCr-Ni thermocouple (K-Type)
The application range of a NiCr – Ni thermocouple of the K type
is from –270 °C bis +1,300 °C.
As the name implies, the themocouple delivers a voltage. This
temperature-dependent voltage is generated at the contact
junction of two dissimilar metals. It is called contact or thermal
voltage. Due to the steady thermal movement of the electrons
in the metal’s lattice; some electrons at the surface can leave
the lattice. This requires energy to break loose from the lattice
and surmount the bonding forces. If now two metals are joined
which have different bonding forces, electrons will leave the
metal with the lower bonding forces and flow to the one with
the higher bonding forces. If two such junctions are arranged
in a circuit, and if both junctions are at different temperatures,
a current will flow.
Temperature measurement with the NiCr – Ni thernocouple:
– The NiCr wire and the Ni wire are connected by junctions
at both ends.
– The junction 1 (KS1) , in our case, is assumed to have the
higher temperature with respect to junction 2 (KS2).
– Due to thermal movement at junction 1, electrons will break
loose in the NiCr wire from the metal lattice.
– The electrons will flow to the Ni wire and constitute the drift
current I1drift.
– The drift current I1drift flows through the junction 2 (KS2)
and there constitutes the diffusion current Idiffusion.
– At the junction 2 (KS2), due to the thermal movement, also
a drift current I2drift is generated.
–I2drift opposes the drift current I1drift at junction 1 (KS1).
–I2drift also causes a diffusion current at junction 1 (KS1).
– The total current Itherm follows from the addition of the
currents, observing their polarities: Itherm = I1drift + I2drift
– If the temperature at junction 1 (KS1) is lower than that
at junction 2 (KS2), the direction of current flow Itherm will
reverse.
Contact junction KS1
Temperature TKS2 >TKS1
Elektrons in
the metal’s
lattice
Idrift
Wire Ni
–1,9 mV/100K
RL
A
SENSE
HI
max. max.
850 850
Vpk Vpk
dependence of the cables, thermoelectric voltages and the
voltage drop across the cable resistances influence the PT100
measurement.
,
max.
250Vrms
LO
Measurement voltage
UPT100
PT100
Itherm
I1drift
I2drift
CAT II
RL
If utmost accuracy is not required, a 2-wire measurement setup may suffice. Due to the fact that the measurement point
with the PT100 and the measuring instrument are mostly at
different temperatures, a temperature change of the cables to
the PT100 causes a change of resistance RL. This temperature
Idiffusion
KS2
Contact junction KS2
Temperature TKS2 <TKS1
Subject to change without notice
49
T e m p e r a t u r e m e a s u r e m e n t – If the temperatures at both junctions are identical, the
currents I1drift and I2drift will cancel.
7.5Reference
junction
In order to characterize the various metals and
their thermoelectric properties, the temperature
dependence of the metals with respect to platinum was determined and recorded in the thermoelectric voltage table, which gives the voltage
in mV/100 K relative to platinum and for the cold
HINT junction at 0 °C.
The measurement
junction 1 is connected to the measurement system by
socalled extension
wires which are
made of the same
materials that form
junction 1. As a rule,
the signal has to be sent over quite a distance, therefore the
extension wires have to be contacted to regular copper wires.
These contacts form a pair of junctions which constitute junction 2. In order to guarantee a decent accuracy, those contact
terminals are mounted on a socalled isothermal metal block
with a temperature sensor; a standard regulation circuit keeps
the block on 0 °C.
Thermoelectric voltage table
Cold junction reference temperature 0 °C
Measuring temperature 100 °C, in [mV/100 K]
PlatinumNickel
(Pt) (Ni)
0,0
-1,2 ...-1, 94
Copper Iron
Ni-Cr
(Cu)(Fe)(CrNi)
+0,75
+1,88
+2,2
Sensing element
Copper cable
NiCr wire
Temperature
TMeas
Vtherm
Ni wire
Copper cable
TRef = const
Isothermal block
Reference junction KS2
TRef = const
Mesurement
location
KS1
If the junction 2 (KS2) is considered as the reference and kept on
a constant temperature, the other junction 1 (KS1) may be used
for temperature measurement. The thermal voltage is proportional to the temperature difference between both junctions:
Itherm proportional to ΔT = TKS1 – TKS2
(Seebeck effect)
50
Subject to change without notice
An early auxiliary method used melting ice to keep the block
temperature constant; this works quite well, with a deviation
of < 1 mK, until all the ice is gone. In practice, this is quite
cumbersome. Who would like to carry a bowl of water and an
ice block around? And this only to just check the temperature
of an oven in the production line. In order to save the customer
from pushing a cart with all the utensils necessary for creating
a reference junction including a refrigerator, most measuring
instruments feature an internal reference junction. All that is
needed is the thermocouple and the appropriate measuring
instrument – the HM8112-3. Thermocouples are less expensive than platinum sensors; in industrial applications there
are often hundreds which are connected to the measuring
instrument via a scanner.
I n t r o d u c t i o n t o t h e o p e r a t i o n o f t h e H M 8 1 1 2 - 3
8Concept of the HM8112-3
8.1Reference
The integrated AD converter has to be connected to a reference.
The characteristics of this reference determine the long term
stability of the instrument. The reference of HM8112-3 is therefore a high precision reference device.
8.2Integrated AD converters
Converters applying the multi slope method are used for AD
conversion.
8.3Moving average
be calculated from the frequency. This combined measurement
of the number of zero points and of the period of a signal allows
the measurement of very small as well as very high frequencies
within a reasonable time. Applying of a DC voltage results in a
frequency displayed of 0 Hz.
As the period is calculated from the measured frequency division by zero will be made. Therefore the instrument will display
„INF“ if the period of a DC voltage is measured („INF“ = infinity).
RMS rectifier
The AC voltage is measured by a high precision RMS rectifier
device. This device gauges a DC voltage proportional to the
applied AC voltage. This DC voltage is equivalent to the true
RMS value of the AC voltage.
Measurement of the crest factor
For crest factors exceeding 7 an AC voltage or current measurement will be incorrect due to the true RMS converter.
9Introduction to the operation of the HM8112-3
Especially before the first operation please pay attention to the
following points:
– The line voltage, indicated on the rear panel of the instrument must correspond to the line voltage used.
– Operation is only allowed from 3 terminal connectors with
a safety ground connection or via isolation transformers of
class 2.
– No visible damage to the instrument.
– No damage to the line power cord.
– No loose parts in the instrument.
Factory settings
The value determined by the AD converter could be displayed
without prior computations, also the average calculated from
n – values could be shown. First of all 1 to n values will be
logged. Averaging over these values will be done, and subsequently this average will be displayed. After 120 values the
next value n+1 will be quantified by the AD converter. The primary measured value 1 will be abolished and a new average
will be calculated from the remaining values ( 2 to n) and from
the new value n+1. This has the advantage that peaks and interferences will be smoothed.
The following values are set by default:
– The measurement range is
– The sampling rate amounts to – The function „1:Filter“ is
– The temperature is displayed in
– The selected temperature sensor is
– The data logger is
– The RS-232 interface is
10 VDC
100 ms
OFF
°C
PT100
OFF
OFF
8.4Measurement of alternating values
Frequency, period
Frequency and period are both measured by a pulse-counting
circuit. Time base is 1 second. The first falling edge triggers
the measurement and starts the counter. For one second
every falling edge will trigger a counting pulse. After expiry of
this term the measurement circuit will wait for the next zero
point. Hence the signal’s period is measured. The time will be
measured until the next zero point occurs. The measurement
result determines the frequency of the signal and the period will
Subject to change without notice
51
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 2
3 4
5
27
1
6
7
8
9
10 11
12 13
14 15
16 17
10Control elements and displays
10.1General functions
1 Display
16 digit display for displaying measurement results, menu
selection and menu items.
2 POWER
Button for activating standby-function. The controls and the
display are turned off. The instrument itself stays turned on
as long as it is connected to the supply voltage. This has the
advantage that the instrument is immediately functional after
turn-on. Also the reference voltage source will remain energized, so any drift after turn-on will be eliminated, also its long
term drift will be substantially improved.
To switch-off the instrument completely, the line switch on the
back panel has to be operated.
3 HOLD
“Freezing“ of the displayed measured value.
By pressing one of the function selection buttons 6 to 15 or
MENU 18 the HOLD function is left.
4 ZERO
Zero for DC voltage, DC current, 4-wire-resistance and 2-wireresistance measurements. The ZERO function is not provided
for AC voltage and AC current measurements. Both cables
have to be shorted and the ZERO button has to be pressed.
This results in elimination of the resistances of the measurement cables, resistances and thermal voltages at the junction
of different metals.
Compensation values remain, even after turn-off the instrument. They have to be redetermined if necessary.
The ZERO button is deactivated in the measuring
functions δPT for PT sensors or δTH for thermocouples.
Zero adjustment with temperature measurement
1. With regard to the type of temperature sensor one the following measurement ranges must be chosen:
PT100Ω 2 wire / Ω 4 wire
1 kΩ range
PT1000Ω 2 wire / Ω 4 wire
10 kΩ range
Thermocouple VDC
100 mV range
52
Subject to change without notice
19 20
18 21
22 23
24
25
26
Whether 2-wire- or 4-wire-measurement has to be selected
depends on the PT temperature sensor used.
2. Short the temperature sensor.
3. The ZERO button 4 is to be pressed to compensate for
influences within the measurement circuit.
4. After compensation jump to the adequate temperature
measurement function by pressing ZERO 4
Some measurement instruments offer an „automatic zero function“. This function regularly interrupts the measurement and shorts the input. Then
a partial 0-adjustment is made.
The HM8112-3 has no auto zero function, because the zero adjustment of the complete measurement circuit is very important.
5 LOCAL
By sending a command via interface to the HM8112-3 the instrument is set to the remote mode. Remote control is switched off
by pressing button LOCAL. The instrument returns to manual
mode and can be operated from the front panel.
10.2 Buttons for the various measurement functions
If the measurement function is changed, the HM8112-3 assumes
the sampling rate selected, unless a sampling rate between 10 s
and 60 s is chosen. Then changing the measuring function will
set the sampling rate automatically to 1 s.
The buttons offering more functions are illuminated. Naturally, other measuring functions can be called up by pressing
unlighted buttons.
The terminals are illuminated, too, and indicate the terminals
to be used with the corresponding functions.
Voltage Measurement
6 VDC
FUSE
1A
F250V
max. INPUT
600V rms / 1A rms
V
A
SENSE
+
Direct or
alternating voltage
–
HI
max. max.
850 850
Vpk Vpk
Ω, ϑ
max.
250V rms
LO
CAT II
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.
Frequency and period
FUSE
1A
F250V
max. INPUT
600V rms / 1A rms
V
8 VAC
A
SENSE
Alternating voltage measurement up to 600 V, true RMS without the DC component. 100mV range is not possible. In AC a
capacitor is inserted. The input impedance of the HM8112-3 is
Ri = 10 MΩ.
+
HI
Direct or
alternating voltage
max. max.
850 850
Vpk Vpk
–
Ω, ϑ
LO
max.
250V rms
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 VDC. The
input impedance of the HM8112-3 is 10 GΩ in 100 mV range,
10 MΩ in the other ranges.
Current measurement
Direct current
measurement.
Auto range function up to and
including
the range 1 A
V
A
SENSE
+
HI
max. max.
850 850
Vpk Vpk
Direct or alternating current
Ω, ϑ
–
LO
max.
250V rms
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 VAC measurement is taken. Is necessary to
measure the alternating voltage in VAC first and
afterwards call up the FREQ./PERIOD function.
FUSE
1A
F250V
max. INPUT
600V rms / 1A rms
7 ADC
CAT II
CAT II
9 AAC+DC
Alternating current measurement, true RMS with DC component. 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 .
Temperature measurement
Switching between 2-wire and 4-wire measurement by repeatedly pressing δPT-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 measurements 100 mΩ is stored
by default. This value can be changed via interface.
For exact measurements it is necessary to calibrate 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 measurement (see ZERO 4 ).
13 δPT with 4-wire-temperature measurement
FUSE
1A
F250V
max. INPUT
600V rms / 1A rms
11 Ω 2-wire
resistance
measurement
For compensation
of the wiring resistance with 2-wire
measurements
100 m Ω is stored by
default. This value
can be changed via
the interface.
V
FUSE
1A
F250V
max. INPUT
600V rms / 1A rms
V
+
A
SENSE
resistance
measurement
+
HI
max. max.
850 850
Vpk Vpk
Ω, ϑ
(Sense)
–
max. max.
850 850
Vpk Vpk
HI
+
LO
–
(Source)
CAT II
–
LO
Power
input
Ω, ϑ
max.
250V rms
2-wire
max.
250V rms
A
SENSE
Voltage
measurement
4-wire-temperature measurement with PT100
CAT II
Measuring method:
4 wire resistance measurement with linearisation according to EN60751 for PT100 and PT1000.
11 Ω 4-wire resistance
measurement
FUSE
1A
F250V
max. INPUT
600V rms / 1A rms
V
Voltage
measurement
A
SENSE
+
(Sense)
–
Resistance measurement
4-wire
Power
input
HI
max. max.
850 850
Vpk Vpk
Temperature sensor:
PT100, PT1000 resistance sensors
(Source)
Ω, ϑ
max.
250V rms
+
LO
CAT II
–
Display range:
Celsius:
Fahrenheit:
Test current:
Test voltage
(open circuit):
Display scaleResolution
–200 °C to +800 °C
0.01 °C
–328 °F to +1472 °F 0.01 °F
PT100
1 mA
PT1000
100 µA
2.5 V
Subject to change without notice
53
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:
Delay:
Calibration:
Linearisation:
100 ms to 60 s
100 ms (after change of function or range)
with resistance measurement standard
PT100 1 kΩ range
PT1000
10 kΩ range
according to EN60751
10.3Continuity test
14
Continuity and diode test
FUSE
1A
F250V
max. INPUT
600V rms / 1A rms
V
A
SENSE
13 δPT with 2-wire-temperature measurement
Limited accuracy of measured values for 2-wire-temperature
measurement with platinum temperature sensors PT100 or
PT1000.
max. max.
850 850
Vpk Vpk
V
A
Power
input
+
HI
max. max.
850 850
Vpk Vpk
Ω, ϑ
(Source)
–
LO
max.
250V rms
CAT II
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
FUSE
1A
F250V
max. INPUT
600V rms / 1A rms
V
A
SENSE
+
thermocouples
–
HI
max. max.
850 850
Vpk Vpk
Ω, ϑ
max.
250V rms
LO
CAT II
Measuring method: Voltage measurement in 100 mV range with linearisation according to EN60584.
Display range:
Thermocouples
Range up to °C
J- Type (Fe-CuNi)
–210 to +1200
K – Type (NiCr-Ni)
–270 to +1372
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
LO
–
Continuity
test
CAT II
FUSE
1A
F250V
SENSE
+
Ω, ϑ
max.
250V rms
max. INPUT
600V rms / 1A rms
HI
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 VDC“ is displayed.
The test unit must be at zero potential during continuity test.
10.4Max / 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.
10.5Range selection
Manual range selection
The range can be selected manually by pressing
20 and
23 .
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“.
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
The autorange function is to be used with care.
For measurements on high impedance source and
measurement voltages in the range (90%) of full
scale 1 V, changing to a higher range is possible
with activated AUTO function. The HM8112-3 has
an input impedance of 10MΩ in the 10 V range
instead of 1 GΩ in the 1 V range. By loading a high
impedance source of several 100 MΩ with by input
impedance of 10 MΩ the measurement result will
HINT be errouneous.
10.6Menu structure / Menu prompting
value of 100 ms will be preset. Removal of the line voltage will
not save a selected value.
If the measurement function is changed, the HM8112-3 assumes
the default sampling rate, unless a sampling rate between 10 s
and 60 s is chosen. Then changing the measuring function sets
the sampling rate automatically to 1 s.
Example: The sampling rate for VDC is set to 60 s. Then the function ADC is selected. The instrument will reduce the sampling
rate automatically to 1 s. The new sampling rate applies to all
functions. If a sampling rate greater than 1 s is needed, it has
to be selected after every change of function.
From every measurement function the menu can be entered by
pressing MENU 18 . Within the menu, every button which can be
used is illuminated. The menu can be always left by pressing
ESC 19 without acceptance of entered values.
A sampling rate of 60 s means:
The HM8112-3 integrates the input voltage and the
the reference voltage over a period of 60 s. After
expiry of this time the value calculated will be
displayed by 6½ digits.
Call of the menu by MENU 18 .
20 and
23 . The menu item is
Choice of menu item with
opened with MENU or branch to the next menu level. Selection
of parameters shown with and . Acceptance of parameters
changed with MENU . If the menu is left, the instrument will
return to the last measurement function.
1:Filter
Selection of the number of values taken for averaging. In case
of selection of a number greater than 1, the selected number
will be taken for averaging. By calculating a new averaged value,
the first measured value will be discarded and the mean value
will be computed.
19 ESC
Leaving the menu. Return to the last measuring function without
acceptance of the value entered.
OFF
2
4
8
16
20
Rotating menu prompting. Jump to the next menu item with
every key operation. On reaching the last menu item the display
continues with the first menu item.
23
Rotating menu prompting. Jump to the previous menu item with
every key operation. On reaching the first menu item the display
will roll over and continue with the last menu item.
22 ENTER
Use this button only in the logger menu „6:Logger.“ Switching
to the next buffered value by every key operation or acceptance
of an input.
If the scanner card (HO112) is activated, the individual measuring points will select with a push on
the ENTER button.
10.7Menu structure and function
The menu will be accessed by pressing MENU 18 . It branches
to the submenues described below.
0:Time
The time intervals between the measurements are adjustable
from 0.01 s to 60 s. That means, a reading is taken every 0.01 s
or only every 60 s.
The sampling rate can assume the following values:
10 ms
(only via interface)
50 ms
(only via interface)
100 ms
(default setting after switch-on)
500 ms
1s
10 s
60 s
That means, for example, that every 500 ms a measurement is
taken and the value is updated in the display. After switch-on a
(default setting after switch-on)
2:Temp
In this menu item the dimension for the temperature measurement is selected.
° C
Degrees Celsius
° F
Degrees Fahrenheit
The dimensions selected last will be saved even if the mains
will be turned off.
3: Sensor
Here the temperature sensor used is selected.
After switch on of the HM8112-3 and selection of the menu item
“3:Sensor“, if a measurement function other than temperature
measurement was set, PT 100 as temperature sensor is selected by default. If the thermocouple is chosen the HM8112-3 is
in measurement function δTH 15 .
Also the instrument will return to the measurement function
δPT 13 after selection of the PT-sensor. The sensor type selected last will be stored in the instrument even if the main voltage
is turned off.
– K–type: thermocouples NiCr-Ni (default setting after switchon)
– J–type: thermocouples Fe-CuNi
– PT1000: platinum resistance sensor with R0 = 1000 Ω
– PT100: platinum resistance sensor with R0 = 100 Ω (default
setting after switch-on)
Comp
For measurements with thermocouples a reference with a known
temperature must be defined. This reference temperature is
provided to the HM8112-3. Therfore three methods are possible:
1st: Comp Ext/Ice
An external temperature test point acts as a reference, e.g. an
ice bath or another reference thermocouple with a temperature
Subject to change without notice
55
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 Overview of menu structure – part 1
Call of the menu by:
Special function in the
Logger-Menu
ENTE
see next page
Selection of menu with:
MENU
MENU
Opening menu with:
Choose parameter:
Assuming parameter
and closing the menu:
MENU
Selection of sampling rate
default
0: Time
60s
10s
1s
500ms
100ms
MENU
MENU
default
Filter: Number of values for averaging
1: Filter
16
8
4
2
Off
MENU
MENU
default
Temperature: Selection of dimension
2: Temp
MENU
MENU
last setting
Choice temperature sensor
: Sensor
T100
T100
Fe
CuNi
NiCr
Ni
MENU
MENU
1000
100
m
Fi
default
ing the reference for the thermocouple
Comp
e
Comp
ifi
MENU
ati
n
f an e
te
T Front
sing a
sens
measu ement
nal i
e
at
sens
ν
MENU
f
efe en e
2
int
ele ti n
4
2
T
f
i e measu ement
as
m
mefe en
m
2
t
e
nt
e
MENU
MENU
f
e tan e f t e dis la ed
efe en e
alue
eneral information
ele
:
56
nfo
MENU
Subject to change without notice
ti
n
e si n
al ate
e
MENU
la
e si n 0 0404
al
ate 1 0504
e
0000 104
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
Overview of menu structure – part 2
Math-Menu
5: Math
➡
➡
MENU
Off
Lo Limit
Hi Limit
Offset
➡
MENU
default
Starting / Stopping the data logger, dumping the test series
6: LOGGER
➡
MENU
➡
➡
Start
Stop
Dump
Dump
➡
MENU
➡
00000
➡
ENTER
Dumping the test series
ENTER
ENTER
ENTER
y
MENU
➡
MENU
default
➡
➡
Wert1 00001
➡
➡
or
Wert2 00002
Storage
ESC
nd
lea ing menu
Interface: selecting the baud rate
7: Com
➡
MENU
➡
Rs19200
Rs9600
Off
➡
MENU
last setting
Calibration
8: Cal
This area is protected b
pass ord
Scanner, choice of the channel
9: Mux
➡
MENU
➡
empty
Chanal 1
....
Chanal 8
of 0° C, connected with the closed end to the measuring point,
and the reference put into the ice bath. The closed end of the
thermocouples can be connected with standard measurement
cables to the terminals of the HM8112-3.
2nd: Comp PT-Front
The temperature measured with a platinum sensor is the reference for the measurement used with the thermocouples. If
several thermocouples will be attached to the HM8112-3 via a
scanner, the use of the ice bath would be necessary for each
thermocouple. To overcome this, the ambient temperature or
even a source with a constant temperature is taken as the reference (e.g. ice bath, heated reference). If “PT-Front“ is seleced
by pressing MENU 18 the function δPT will be activated. Now
2- or 4-wire measurement can be chosen. Then the reference
temperature is measured with a platinum sensor and assumed
by confirmation with button MENU 18 . In case of 2-wire measurement the PT-sensor can stay connected to the thermocouple.
➡
MENU
default
For 4-wire measurement it has to be disconnected and replaced
by the connection of the thermocouple.
3rd: Comp 23° C/ °F
A temperature of 23° C is specified as reference. For measurements of high temperatures the resulting measurement error
can be neglected, unless the open end of the thermocouple
is on the level of the ambient temperature. The ambient temperature should be about 23° C.
4:Info
In this menu item all instrument information is available:
Version:
Display of revision number of the software
Ser-Nr:
Display of the intrument’s serial number
Cal date:
Display of the date of the last calibration.
5: Mathematics
Analysis of different characteristics of the measured values
Subject to change without notice
57
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 OFF The menu item 5:Math is off.
Lo Limit Lower limit.
If the measured value is smaller than the Lo Limit value an acoustic warning sounds and
“Lo limit is displayed.
Hi Limit Higher limit.
If the measured value is greater than Hi Limit value an acoustic warning occurs and „Hi limit“ is displayed.
Offset An offset value can be set for all measurement functions 6 to 15
a) Apply the offset value to the terminals.
b) Choose menu item 5:Math.
23 .
c) Select submenu „Offset“ by pressing
d) Open the submenu with MENU 18 , the offset value applied will be displayed.
e) Accept the offset by pressing MENU 18 .
f) Return to measurement function, the display shows 0,00…., , the dimension and „Os“.
g) Now you can connect the value to be measured. It is compared the calibrated value and the deviation is displayed.
In order to delete the stored offset:
a) Choose menu item 5:Math.
23 .
b) Select submenu „Off“ by pressing
c) Accept by pressing MENU 18 , return to measurement function, the measured value is displayed without offset.
or d) select another measurement function.
The offset value will not be stored when the measurement function is changed.
6:Logger
Analysis of different characteristics of the measured values
Start
Stop
Dump
The test series is started. According to the selected sampling rate in „0:Time“ every xx second a reading is taken and stored.
The test series is stopped.
The test series is shown on the display. Each time
button ENTER 22 is pressed the next value of the
stored test series is displayed.
7:COM
In this menu the baud rate can be chosen. Either 9600 baud or
19200 baud are available. The remaining interface parameters
cannot be changed.
Interface parameters (adjustable)
Rs Off
The interface is switched off
Rs19200
19,200 baud
Rs9600
9,600 baud
Interface parameters (not selectable)
N
no parity bit
8
8 data bits
1
1 stop bit
Xon-XoffXon-Xoff
Every transmission of a character takes 1 ms. Selecting a sampling rate of 0.01 sec requires a baud
rate of 19 200.
8:Cal
This menu is saved by password. In order to guarantee exact
measurements the HM8112-3 is calibrated. Calibration may only
be done with adequate precision reference sources. For this
purpose the password can be orderd at HAMEG GmbH (Phone.:
(+49) 06182-800-500 or via E-Mail: [email protected]).
58
Subject to change without notice
Attention:
After receiving the password any warranty claims of HAMEG
GmbH concerning the compliance with the technical specifications of the instrument become void.
9:Mux
For the future implementation of a scanner/test point switch.
10.8Measurement inputs
24
25
26
27
For connection measurement signals the HM8112-3 features 4
safety connectors on the front panel. Depending on the measurement function chosen, the active terminals will be illuminated.
The terminals on the front panel are safety connec-tors and the regulations have to be observed.
If connecting dangerous voltages to the input terminals 24 and 26 all relevant safety regulations are to
be observed.
DC voltage must be floating!
AC voltage must be floating by use of a safety isolating transformer.
Attention!
Voltages exceeding one of the following values are
regarded potentially dangerous or even lethal:
1st
30 Vrms
2nd
42.4 Vpeak
3rd
60 VDC
Connecting higher voltages is only allowed by skilled
personnel who are familiar with the dangers incurred. The relevant safety regulations are to be strictly
observed!
24 V/SENSE (4mm safety sockets)
Connection of measuring cables for:
– voltage measurement
– frequency measurement
– 4 wire resistance measurement (SENSE)
– continuity test
– temperature measurement by a thermocouple
– 4 wire temperature measurement by a P-temperature
sensor (SENSE)
The maximum voltage between HI and LO case
(ground) must not exceed 850 V-peak or 600 VDC.
The maximum voltage between LO and case
(ground) may not exceed 250 Vrms!
S c a n n e r C a r d H O 1 1 2
26 A/SOURCE (4mm safety socket)
Connection of measuring cables for:
– current measurement, max. 1 ampere
– 2 wire resistance measurement
– 4 wire resistance measurement (SOURCE)
– 4 wire temperature measurement by a PT-temperature
sensor (SOURCE)
– continuity test up to 10 Ω
The maximum current may amount to 1 Aeff!
25 LOW (4mm safety connectors)
Ground connection for inputs 24 and 26 . Both connectors are
high-impedance DC-isolated.
27 Fuse in the current measuring circuit
The shunt is fuse-protected. The fuse (FF) is located in a fuse
holder. The measuring circuit is designed for a maximum allowable measurement current of 1 ampere.
Replacement of the fuse is only allowed, after the
instrument was disconnected from the mains!
A repair of a defective fuse or bypassing the fuse is
very dangerous and absolutely prohibited!
11Scanner Card HO112 (option)
Miscellaneous:
With built-in Scanner Card HO112 voltage measurements are only
possible up to 100 V. That means that the 600 V range of the voltage
measurement functions is automatically inactive.
Pin 1 is the ground connection. Channel BP is used to supply the
other channels with current, e.g. for suppling sensors, LEDs etc.
Commands:
03A0 all channels are off
03A1 channel 1 active
03A2 channel 2 active
03A3 channel 3 active
03A4 channel 4 active
03A5 channel 5 active
03A6 channel 6 active
03A7 channel 7 active
03A8 channel 8 active
03A9 front channel
active
Pin assignment:
AHI
VHI
AHI
VHI
AHI
VHI
AHI
VHI
AHI
VHI
AHI
VHI
AHI
VHI
AHI
VHI
AHI
VHI
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
19
10.9Replacement of the measuring circuit fuse
37
ALO
The measuring circuit fuse 27 is accessible from the front panel.
A replacement of the fuse is only allowed, if no voltage is applied
to the measuring connectors! Therefore all terminals V/SENSE
24 , ground 25 and A/SOURCE 26 should be disconnected. The
cover of the fuse holder has to be turned ccw with a screw driver
having a suitable blade. As the cover can be turned it has to be
pushed by the srew driver into the fuse holder. The cover with
the fuse can then be easily taken out. Replace the defective fuse
by a new fuse of the same type having the same trip current. A
repair of a damaged fuse or the use of other means for bypassing
the fuse is very dangerous and absolutely prohibited! Damages
incurred will void the warranty.
10.10Rear Panel
28 Power receptacle with power switch
Power receptacle for connecting the line cord with according
to DIN49457.
36
VLO
BP
35
ALO
34
VLO
33
ALO
CH1
32
VLO
CH2
31
ALO
30
VLO
29
ALO
CH3
28
VLO
CH4
27
ALO
26
VLO
CH5
25
ALO
24
VLO
CH6
23
ALO
22
VLO
21
ALO
CH7
20
VLO
CH8
Specifications
Channels:
8 (4-wire)
Switching:
bistable, floating relais
Thermal voltage:
typ. 500 nV, max. 1µV*)
Max. voltage between 2 contacts: 125 Vpk
Max. measuring voltage: 125 Vpk - also V/Ω-input Volt-Hertz-Product:
≤ 1 x 106 V · Hz
Max. switching current:
1 Aeff
Max.contact resistance: approx. 1 Ω (each wire)
Life time:
2 x 108 switches (0.1 A; 10 VDC)
Insulating resistance:
3 GΩ **)
Capacity:
>100 pF, between contacts
Switching delay:
20 ms
Measurement delay:
between 50 ms and 300 ms
*) max. 1µV after a warm-up of 1.5 h
**) at rel. humidity < 60 %
29 Interface
The USB/RS-232 interface is located at the rear panel of the
HM8112-3. The interface of HM8112-3 can receive data (commands) from an external device (PC) or send data (measurement
values and parameters). The following option is available: HO880
IEEE-488 (GPIB). In order to avoid the warranty seal broken we
recommend the installation ex factory.
30 Voltage selector
Choice of mains voltage (115 V / 230 V).
29
28
30
Subject to change without notice
59
R e m o t e O p e r a t i o n 12Remote Operation
The Dual Interface USB/RS-232 HO820 and the GPIB interface
HO880 are electrically isolated from the measuring circuit.
The instrument is programmable by a PC. Functions and ranges
can be selected and measurement values stored in the instrument can be read out. The respective drivers are available on
the enclosed Product CD or can be downloaded at http://www.
hameg.com.
Notes concerning some commands:
0000…0004 Measurement of DC voltage, ranges 100 mV to 600 V
0010…0014 True RMS with DC
0016…0019 True RMS without DC
02C3…02C5 This message is sent after a change of function or range
02F0…02F3 Request of the instrument’s data
HINT
The HM8112-3 is connected to another instrument
by a 1:1 interface cable. It is recommended to use a
9 to 25 pin standard adapter if a PC with a 25 pin
HINTCOM port is connected.
Interface parameters RS-232
Settings: No parity bit, 8 data bits, one stop bit, Xon-Xoff
Baudrate: The communication is carried out with 9600 baud.
USB interface
You do not have to change the configuration. If required, the
baud rate can be changed. Connect the HM8112-3 with your PC
using a USB cable and install the USB drivers like described in
the manual of the USB interface HO820.
GPIB interface
It is necessary to change the GPIB adress of the function generator to the desired value. The adress is changed at the interface
on the back panel. Connect the HM8112-3 with your PC using a
GPIB cable and set the baud rate to 9600 baud.
By pressing button „LOCAL“ the instrument returns to manual mode.
13.2Command reference
Group 0 controls all measurement functions. If a measurement
time > 1s was selected, it will be set to 1 s after any change of
function. A change of range will not affect the measurement time
selected. A change of function or range will, however, always
cause a fresh selection of filters.
Function 0 to 5:
This parameter selects the range, autoranging will be disabled.
Parameter 9 (no change) will retain the previous range selection.
Function 1:
Parameters 0 to 4 select DC coupling, 6 to 9 AC coupling.
Function 8:
FREQ VAC requires a valid parameter 1 or 2. During frequency
measurement the voltage measurement will be disabled, hence
also autoranging. The range previously selected in the function
VAC will be retained.
Function B:
Diode test with parameter 9.
13 Data communication
13.1Layout of commands
A command consists of 5 ASCII characters:
1.
2.
3.
4.
5.
Character: 0
Character: Command category (0, 1, 2 or E)
Character: Function between 0 and F
Character: Parameter between 0 and F
Character: Terminator, either CR or LF
– all commands end with CR or LF
– the character set includes figures 0 – 9, characters A – F
and CR, LF
– the characters can be entered as upper case or lower case
letters
– Figures 2, 3 and 4 received after 0 are interpreted as a
control command. After a command has been transmitted
a delay of at least 35 ms must be observed, then the next
command can be sent.
– A transmission of invalid commands is answered with 02D0
in case of wrong length of the command or void command
category, with 02D1 for group 1, with 02D2 for group 2 and
with 02DE for group E. This helps debugging the controller
program. The error message is transmitted immediately
after occurrence.
60
Subject to change without notice
Function C:
Continuity test with parameter 6 (Rthreshold = 10 Ω).
Functions D and E:
2- or 4-wire-temperature measurements require parameter
3 for PT100 or 5 for PT1000.
Function F:
Temperature measurement with thermocouple, requires parameter 1 for type J or 2 for type K.
Group 1 controls the measurement functions of the instrument.
Function 0 (Autorange):
– Parameter 0 turns autoranging off.
– Parameter 1 turns autoranging on.
– Parameter 8 selects the next higher range until the highest
is reached.
– Parameter 9 selects the next lower range until the lowest
is reached.
Function 1 (Meas – Time):
– Parameter 1 to 7 select the measurement time from 10
ms to 60 s. The measurement results are available at the
interface with the measurement time chosen.
– Parameter 8 selects the next higher measurement time
until the longest is reached.
– Parameter 9 selets the next lower measurement time until
the shortest is reached.
D a t a C o m m u n i c a t i o n
Function 4 (Math Program):
– Parameter 0 turns the math function off. Autoranging is
disabled. If desired autoranging must be turned on by the
command 0101. If the Min/Max function is turned off on the
keyboard autoranging will be automatically chosen.
– Parameters 1 to 3 select one of the math functions OFFSET,
HIGH LIMIT, LOW LIMIT; the last result sent will be automatically taken as the reference value. If the HIGh LIMIT or
LOW LIMIT is reached a continuous beep will be sounded,
the interface will transmit 999999.9.
– Parameters 7 and 8 turns the Min/Max function on, autoranging will be disabled.
– Parameter 0 turns the buffer off.
– Parameter 1 turns the buffer on.
– Parameter 2 will cause transmission of all results in the
buffer.After the last result was sent the message 01A6
(buffer empty) will be transmitted.
– Parameter 3 issues the oldest result in the buffer memory. After transmission of the last result the message 01A6
(buffer empty) will be transmitted.
– Parameter 4 erases the buffer. This is necessary after any
change of function or range as it is no longer possible to
identify function or/and range of each result. The same holds
for other changes of parameters like measurement time,
filter etc.
– Parameter 5 will erase the buffer automatically after any
command of group 0 and the commands 0108 or 0109. The
command 01A4 will disable this function.
– Paraneter 6 will inform that the buffer is empty.
Function 6 defines the trigger modes.
– Parameter 0 selects autotrigger. This means that each new
result will be automatically transmitted after the measurement time (011X) selected has elapsed.
– Parameter 1 selects single trigger. Each command 0161
triggers just one measurement. Buffer operation and storage of results will not be affected. Single trigger operation
will not cause any storage of results either in the buffer or
in the results memory.
Function B (record no.)
– Parameters 1 to F select a result memory which then may
be read by Storage Dump (0192) or Storage Single Dump
(0193). The function 01BX will send an information about
the header of the memory selected using the form 0XX for
function and range and 011X for the measurement time. In
case a memory selected is empty 0196 will be transmitted.
The instrument will automatically number the memories
starting with 1.
Function 7 (Zero) activates zero adjustment.
– Parameter 1 causes the next result to be taken as zero
reference and to be stored in the E2PROM non-volatile
memory.
Function C (Temp Comp) defines the reference compensation
method in case of temperature measurement with thermocouples.
– Parameter 0 compensates for the reference joint at 0 degrees C.
– Parameter 1 (23 degr. C) assumes a reference joint temperature of 23 degr. C.
– Parameter 2 (FRONT) takes the last temperature measurement result from a PT100 or PT1000 measurement
(2- or 4-wire) and uses it for compensation. When using a
2-wire-sensor a PT sensor and a thermocouple may be
connected simultaneously thus allowing switching back
and forth.
Function 2 (Filter length) inserts a continuously averaging filter.
– Parameter 0 turns the filter off.
– Parameter 1 to 4 select the number of measurement results
averaged (2,4,8,16).
Function 8 (Result) defines the format of the results.
– Parameters 4 and 5 alternate between degrees C and F in
the temperature measurement modes.
Function 9 (Storage) controls the results memory. Single
trigger (0161) or buffer (01A1) modes will not affect the
memory. The results memory may be written to and read
independently.
– Parameter 0 stops the storage of results.
– Parameter 1 starts the storage. Locations are used starting
from 1 always using the next free one up to a maximum of
15. The memory header contains the function, the range,
and the measurement time.
– Parameter 2 causes the transmission of all results contained in a memory which first must be selected by the
command 01BX. This transmission will not be interrupted
by any new results. If a memory shall be read several times
it has to be selected each time by the command 01BX.
– Parameter 3 will cause transmission of the next result
(starting with the first one) of a memory which first must
be selected by the command 01BX. This command allows
to control the speed of result transmission.
– Parameter 4 will erase the complete result memory.
– Parameters 5 to 7 are status informations. 0195 signals the
end of result transmission from a memory. 0196 signals
that a memory selected by 01BX is empty. 0197 signals that
either all 32,000 locations or all 15 records are occupied.
Function A (Buffer) controls the result buffer. Results will not
any more be transmitted automatically, instead they are
stored in a ring buffer which holds the last 15 results. Unless the results are fetched by the commands 01A2 or 01A3
the oldest result will be overwritten. In case the autostatus
function is selected the transmission of status information
will be inhibited, this information will be lost (see commands
02C4 and 02C5). Without a command from the controlling
unit the instrument will not transmit any information.
Function F (Test):
– Parameter 1 causes a RAM test which does not destroy any
data. The test result will be transmitted either with 01F4
(RAM GOOD) or 01F5 (RAM FAIL).
Group 2 selects the interface modes and diverse information.
Using a IEEE interface (HO880) the baud rate has to be set to
9600 baud.
Function 2 (Com) will be stored in the E2PROM (default value
9600).
– Parameter 0 turns transmission off.
– Parameter 3 selects 9600 Baud and turns the transmission
on.
– Parameter 4 selects 19200 Baud and turns the trans-mission on. This baud rate is mandatory for 10 ms measurement
time and transmission.
Function C (Message) delivers instrument status information.
– Parameter 2 will transmit the complete instrument status.
In turn information of groups 0 and 11 to 15 will be transmitted. The status informations 0197, 0198, and 01A6 will
be transmitted if they were activated. The command 02C2
will cause the transmission of the following informations:
Subject to change without notice
61
D a t a C o m m u n i c a t i o n Answers:
PARAMETER:
00XX Measurement functions
0-6, 9 Ranges and sensors
010X Autoranging
0,1
Off or On
011X Measurement time 1-7
10 ms to 60 s
012X Filter length
0-4
Off, 2 to 16
014X Math program
0-3, 7, 8Off, Offset, High Limit, Low Limit, Max, Min.
016X Trigger mode
0,1
single or auto
018X Temp. Selection 4,5
degree C or F
019X Results memory
0,1
Off or On
019X Results memory
7
Full
019X Results memory
8
Single result storage
01AX Results buffer
0,1
Off or On
01AX Results buffer
5
Autoclear selected
01CX Temp. compensation 0,1,2 External, 23 degr. C, PT temperature
measurement
– Parameter 3 disables the auto status function (02D4) and
the continuous status function (02D5).
– Parameter 4 turns the auto status function (02D4) on. The
continuous status function (02D5) will be disabled if active.
If commands are sent via the interface all commands of
groups 0 and 1 will be echoed immediately, asynchronously
to the measurements. If commands are received which are
not implemented 02DX will be sent (helpful when looking
for errors in the control program). The following informations will be issued immediately after any keyboard operation or in case of, e.g., result memory full, auto range:
00XX, 0100, 0101, 0111-7, 0140, 0147, 0148, 0182-5, 0190,
0191, 0198, 01C1, 01C2.
– Parameter 5 turns the continuous status function on. The
auto status function, if active, will be disabled. After each
result obtained the actual function and range will be transmitted in the format 00XX, followed by the transmission of
the measurement time in the format 011X. Any information
of group 1 caused by a status change of the instrument will
be stored and transmitted in place of the measurement
time synchronously with the next result. In case there will
be more than one group 1 information caused by a keyboard
operation or by the instrument’s control program (e.g. result
memory full, auto range) within the same measurement cycle those informations will overwrite each other. Only the last
information will be transmitted with the next result. Range
or function changes via the keyboard may cause several
group 1 informations. Hence only the status of the auto
range function will be transmitted, messages concerning
changes of the functions Max/Min or the result memory will
be suppressed. (this does not apply to commands received
via the interface). These status changes may be taken from
the following table:
Change of range
Change of function
Max/MinResult memory
restart
off
off
off
Full information about the instrument status may be received by the command 02C2.
The auto status function has this format:
+/-X.XXXXXX
Result with sign
0XX
Function and range
1XX
Group 1 information
The following group 1 informations are transmitted: 0100,
0101, 0111-7, 0120-4, 0140-4, 0140-143, 0147, 0148, 0184-5,
0190, 0191, 0198, 01C0-1C2.
62
Subject to change without notice
If buffer operation is active (01A1) the auto status function
will remain active, function, range, and group 1 information
will be be stored in the ring buffer together with the results.
The description of the auto status function remains valid in
full. Any commands of groups 0 and 1 will be echoed after
their execution. These echoes may be used for handshaking
obviating any waiting times.
Function F (data) provides instrument information.
– Parameter 0 issues the 6 digit software revision number
XXXXXX.
– Parameter 1 issues the last calibration date in the format
DDMMYY
- Parameter 2 issues the serial number.
- Parameter 3 issues the milliohms of the cable resistance
compensation in case of 2-wire PT100- (PT1000-) temperature measurements.
2nd
0
2
1
0
Character Group
1st
0,1mA
100Ohm
3 IAC
4 OHM 2WIRE
-
C Continuity
F Sensor TH
-
2 Com RS232
LENGTH
F Info - data read
-
OFF
C MESSAGE
-
EXT/ICE
C Sensor Comp
Subject to change without notice
LAST CAL
GROUP 1
-
-
RAM
23°C
1
ON
OFF
START
STOP
-
OFFSET
2
10ms
ON
J
-
-
-
-
FREQ
1kOhm
1kOhm
1mA
1mA
1V-DC
ZERO
-
F TEST
1
1V
-
A BUFFER
9 Storage
8 Temp
7 ZERO
OFF
AUTO
6 TRIGGER
CONT
4 Math
1 MEAS-Time
OFF
-
B Diode test
0 AUTO-RANGE
-
100Ohm
0,1mA
2 IDC
5 OHM 4WIRE
100mV-DC
1 VAC
0
100mV
0 VDC
Function
3rd Character
2
GROUP 2
-
-
FRONT
2
DUMP
DUMP
-
-
-
HIGH LIMIT
4
50ms
-
K
-
-
-
-
PERIOD
10kOhm
10kOhm
10mA
10mA
10V-DC
10V
-
9600
-
-
3
-
-
-
LOW LIMIT
8
100ms
-
-
Pt100
Pt100
-
-
-
100kOhm
100kOhm
100mA
100mA
100V-DC
100V
3
4
-
-
AUTO STATE
19200
-
4
CLEAR
CLEAR
°C
-
-
-
16
500ms
-
-
-
-
-
-
-
1MOhm
1MOhm
1A
1A
600V-DC
-
-
CONT STATE
-
RAM FAIL
-
5
AUTO CLEAR
°F
-
-
-
-
1s
-
-
Pt1000
Pt1000
-
-
-
10MOhm
10MOhm
-
-
-
-
5
PARAMETER
600V
4th Character
-
-
-
-
-
-
1V-AC
-
6
-
-
-
-
-
-
6
-
-
-
-
-
10s
-
-
-
-
10 Ohm
Survey of the commands for HM8112-3
-
-
-
-
-
-
8
-
-
-
-
MAX
-
60s
-
-
-
-
-
-
-
-
-
-
-
10V-AC
-
7
-
--> E
-
-
-
-
-->
-
-
-
-
-
MIN
-
UP
UP
-
-
-
-
-
-
-
-
-
-
100V-AC
-
8
9
-
-
-
-
-
F
-
-
-
-
-
-
-
DOWN
DOWN
-
-
-
-
No Change
-
No Change
No Change
No Change
No Change
600V-AC
No Change
LF
or
CR
Character
5th
The commands have to be transmitted as characters or a numeric string in ASCII format. Characters may be lower or upper key. Each command must use CR (Chr (13) corresponds 0x0D)
or LF (Chr (10) corresponds 0x0A) as its end.
14Listing of commands
L i s t i n g o f c o m m a n d s
63
Oscilloscopes
Spectrum Analyzer
authorized dealer
43-2030-2010
*43-2030-2010*
Programmable Instruments
Series 8100
www.hameg.com
Subject
to change without notice
Subjecttochangewithoutnotice
45-8112-0311
(11) 21102013
43-2030-2010(10)21092011
©
HAMEG Instruments GmbH
A©HAMEGInstrumentsGmbH
Rohde & Schwarz Company
ARohde&SchwarzCompany
DQS-Certification: DIN EN ISO 9001
DQS-Certification:DINENISO9001:2000
Reg.-Nr.:
071040 QM
Reg.-Nr.:071040QM
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