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 4 5 6 6 6 6 6 6 7 7 7 8 8 8 8 2 9 10 10 10 10 10 12 12 13 14 14 14 14 14 15 15 15 15 15 16 16 16 16 16 17 17 17 17 18 18 18 18 19 20 20 20 8.3 8.4 20 20 21 21 21 21 21 22 24 24 24 24 27 28 29 29 29 12 30 31 31 31 31 3 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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