Valhalla 4176 User manual

Operation Manual
Model 4176
Programmable Micro-Ohmmeter
VALHALLA
SCIENTIFIC
Need Help? Call 800-548-9806.
www.valhallascientific.com
©2015 Valhalla Scientific, Inc. All Rights Reserved.

VALHALLA SCIENTIFIC INC. CERTIFICATION
VALHALLA SCIENTIFIC INC. WARRANTY STATEMENT
Valhalla Scientific Inc. certifies that this instrument was thoroughly tested, inspected, and found to
meet published specifications when shipped from the factory. Valhalla Scientific, Inc. further certifies
that its calibration measurements are traceable to the National Institute of Standards and Technology to
extent allowed by N.I.S.T.’s calibration facility.
Due to continuing product refinement and due to possible parts manufacturer change, Valhalla
Scientific, Inc. reserves the rights to change any or all specifications without notice.
The warranty period for this instrument is stated on your invoice and packing list. Please refer to these
to determine appropriate warranty dates.
Valhalla Scientific, Inc. will repair the instrument during the warranty period provided it is return to
our repair and calibration facility freight prepaid. No other warranty is expressed or implied.
Valhalla Scientific, Inc. is not liable for consequential damages.
Permission and a Return Material Authorization number (RMA) must be obtained directly from the
factory for warranty repairs. No liability will be accepted if returned without such permission.
4176 Programmable µ-Ohmmeter User & Maintenance
Manual
Edition 1
Copyright © 2004-2005 Valhalla Scientific, Inc. All rights
reserved

Edition 1 …………………………………………………………………….….November, 2004
All Editions and Updates of this manual and their creation date are listed below. The first edition of
the manual is 1. The edition number increases by 1 whenever the manual is revised. Updates, which
are issued between editions, contain replacement pages to correct or add additional information to the
current Edition of the manual. Whenever a new Edition is created, it will contain all of the update
information for the previous Edition. Each new Edition or Update also includes a revised copy of this
documentation history page.
D OCUMENTATION HISTORY

WARNING, RISK OF
ELECTRICAL SHOCK.
Frame or chassis ground terminal
--- typically connects to the
equipment’s metal frame.
Indicates the field wiring terminal
that must be connected to ground
before operation the equipment ---
protects against electrical shock in
case of fault.………………………
Alternating current (AC)
Direct current (DC)
Calls attention to a procedure,
practice, or condition that could
possibly cause damage to
equipment or permanent loss of
data.……………………………….
WARNING
Calls attention to a procedure,
practice, or condition that could
cause bodily injury or death.
Instruction manual symbol affixed
to product. Indicates that the user
must refer to the user manual for
specific WARNING or CAUTION
information to avoid personal
injury or damage to the product.
SAFETY SYMBOLS
CAUTION

The following general safety precautions must be observed during all phases of operation, service, and
repair of this product. Failure to comply with these precautions or with specific warnings elsewhere in this
manual violates safety standards of design, manufacture, and intended use of the product. Valhalla
Scientific assumes no liability for the customer’s failure to comply with these requirements.
Ground the equipment: For Safety class 1 equipment (equipment having a protective earth terminal), an
interrupted safety earth ground must be provided from the main power source to the product input wiring
terminals or supplied power cable.
DO NOT operate the product in an explosive atmosphere or in presence of flammable gases or fumes.
For continued protection, replace the line fuse(s) only with fuse(s) of the same voltage and current rating
and type. DO NOT use repaired fuses or short-circuited fuse holders.
Keep away from live circuits: Operating personnel must not remove equipment covers or shields.
Procedures involving the removal of covers or shields are for the use of service-trained personnel only. Under
certain conditions, dangerous voltage may exist even with the equipment switched off. To avoid dangerous
electrical shock, DO NOT perform procedures involving cover or shield removal unless you are qualified
to do so.
DO NOT operate damaged equipment: Whenever it is possible that the safety protection features built
into this product have been impaired, either through physical damage, excessive moisture, or any other reason,
REMOVE POWER and do not use the product until safe operation can be verified by service-trained
personnel. If necessary, return the product to Valhalla Scientific for service and repair to ensure that safety
features are maintained.
DO NOT service or adjust alone: Do not attempt internal service or adjustment unless another person,
capable of rendering first aid and resuscitation, is present.
DO NOT substitute parts or modify equipment: Because of the danger of introducing additional
hazards, do not install substitute parts or perform any unauthorized modification to the product. Return the
product to Valhalla Scientific for service and repair to ensure that safety features are maintained.
Measuring high voltage is always hazardous: ALL multimeters input terminals (both front and rear)
must be considered hazardous whenever inputs greater than 42V (dc or peak) are connected to ANY input
terminal.
Permanent wiring of hazardous voltage or sources capable of delivering grater than 150VA should be
labeled, fused, or in some other way protected against accidental bridging or equipment failure.
DO NOT leave measurement terminals energized when not in use.
W ARNINGS

P REFACE
This manual contains installation, operating and programming, and configuration information for the
Valhalla Scientific, Inc. Model 4176 Programmable µ-Ohmmeter.
The manual consists of the following chapters:
C HAPTER 1 I NSPECTION AND I NSTALLATION
This chapter contains information on initial inspection, bench use and rack mounting instructions. It also
contains the initial adjustments necessary to start operations.
C
HAPTER 2 S PECIFICATIONS
This Chapter lists all the specification applicable to this model.
C
HAPTER 3 G ETTING S TARTED
This chapter covers the fundamentals of ohmmeter operation. It shows you how to use the ohmmeter's
front & rear panel, how to make connections, and describes the display sections and messages.
C
HAPTER 4 M EASUREMENT M ODES & F UNCTIONS
This chapter explains how to setup the instrument for all standard measurements, temperature
compensated measurements and hi-lo comparison. Also contains information and procedures on how
to configure the settings.
C
HAPTER 5 O PTIONAL F EATURES AND A CCESSORIES
This chapter lists and describes all the optional equipment and accessories available for this model.
C
HAPTER 6 R EMOTE I NTERFACE
This chapter illustrates the remote capabilities and explains how to send commands to the ohmmeter
from remote, and how to retrieve data from remote.
C
HAPTER 7 BCD I NTERFACE
This chapter illustrates the remote capabilities and explains how to send commands to the ohmmeter
from remote, and how to retrieve data from remote.
C
HAPTER 8 R OUTINE M AINTENANCE
This chapter illustrates how to perform routine maintenance to the ohmmeter. It covers the calibration
procedures and fuse replacement.
C
HAPTER 9 S PECIAL P ROCEDURES
This chapter contains a number of useful tips that should be noted when working with inductive loads.
C
HAPTER 10 T HEORY OF O PERATION
This chapter describes the theory of operation of the ohmmeter and its features. It gives a detailed
circuit description and troubleshooting information.
C
HAPTER 11 A DDENDUMS
This chapter lists updates and addendums for this manual.
C HAPTER 12 P ARTS L IST
This chapter lists all the parts and components used in the manufacturing of the ohmmeter.
C
HAPTER 13 D RAWINGS AND S CHEMATICS
This chapter contains all the assembly drawings and schematics for the ohmmeter.

1
. TABLE OF CONTENTS
CHAPTER 1 INSPECTION AND INSTALLATION.......................................................................... 4
1.1 I NTRODUCTION ............................................................................................................................. 4
1.2 I NSPECTION .................................................................................................................................. 4
1.3 L INE V OLTAGE /F USE S ELECTION ................................................................................................. 4
1.4 B ENCH U SE .................................................................................................................................. 5
1.5 R ACK M OUNTING ......................................................................................................................... 5
1.6 S AFETY P RECAUTIONS ................................................................................................................. 6
CHAPTER 2 SPECIFICATIONS ......................................................................................................... 7
2.1 S TANDARD M EASUREMENT M ODE S PECIFICATIONS .................................................................... 7
2.2 T EMPERATURE C OMPENSATOR M ODE S PECIFICATIONS ............................................................... 8
2.3 G ENERAL S PECIFICATIONS ........................................................................................................... 9
2.4 E NVIRONMENTAL AND P OWER R EQUIREMENTS ........................................................................... 9
2.5 P HYSICAL S PECIFICATIONS .......................................................................................................... 9
CHAPTER 3 GETTING STARTED................................................................................................... 10
3.1 I NTRODUCTION ........................................................................................................................... 10
3.2 F RONT P ANEL ............................................................................................................................ 10
3.2.1 Power Switch ........................................................................................................................ 10
3.2.2 Display.................................................................................................................................. 11
3.2.3 Range Selection Keys............................................................................................................11
3.2.4 Function/Numerical Keys ..................................................................................................... 12
3.2.5 TCM Receptacle and LEDs .................................................................................................. 13
3.2.6 HLC LEDs ............................................................................................................................ 14
3.2.7 Remote LED.......................................................................................................................... 14
3.2.8 Source and Sense Binding Post ............................................................................................ 14
3.3 R EAR P ANEL .............................................................................................................................. 15
3.3.1 Line Voltage Switch .............................................................................................................. 15
3.3.2 Fuse Holder .......................................................................................................................... 16
3.3.3 Power Connector.................................................................................................................. 16
3.3.4 HLC Relay Terminal............................................................................................................. 16
3.3.5 RS-232 Connector................................................................................................................. 17
3.4 A PPLYING P OWER ...................................................................................................................... 18
3.4.1 Power-On Default Settings................................................................................................... 18
3.5 C ONNECTING A L OAD TO THE 4176............................................................................................ 19
3.6 R ANGE S ELECTION ..................................................................................................................... 21
3.7 O VERLOAD AND S AFE M ODE ..................................................................................................... 21
CHAPTER 4 MEASUREMENTS MODES AND FUNCTIONS...................................................... 22
4.1 S TANDARD M EASUREMENT M ODE ............................................................................................. 22
4.2 “TCM” - T EMPERATURE C OMPENSATED M EASUREMENT M ODE ............................................... 23
4.2.1 Omni Compensator............................................................................................................... 24
4.2.2 TCM ON ............................................................................................................................... 24
4.2.3 TCS – Temperature Compensator Setup .............................................................................. 24
4.2.4 TCC – Temperature Compensator Calibration .................................................................... 27
4.3 “HLC” - H I -L O C OMPARATOR M ODE ........................................................................................ 28
4.3.1 HLC Relay Terminal............................................................................................................. 28
4.3.2 Setting the Limits .................................................................................................................. 29
4.3.3 HLC ON................................................................................................................................ 30
4.4 U PDATE F UNCTION .................................................................................................................... 31

2
4.4.1 Setting the Display Update Rate and Intensity ..................................................................... 31
4.5 R UN /H OLD F UNCTION ................................................................................................................ 32
4.5.1 Configuring the Run/Hold Function..................................................................................... 33
4.6 P RINT /L OG F UNCTION ................................................................................................................ 34
4.6.1 Configuring the Print/Log Function..................................................................................... 35
4.7 V IEW F UNCTION ......................................................................................................................... 36
4.7.1 Using the View function........................................................................................................ 36
CHAPTER 5 OPTIONAL FEATURES AND ACCESSORIES ....................................................... 39
5.1 O PTIONS ..................................................................................................................................... 39
5.1.1 BCD: Data Output................................................................................................................ 39
5.1.2 GPIB..................................................................................................................................... 39
5.1.3 USB....................................................................................................................................... 39
5.2 A CCESSORIES ............................................................................................................................. 40
5.2.1 Omni Compensator............................................................................................................... 40
5.2.2 Option R: Rack Mount Adapter ........................................................................................... 40
5.3 T EST L EADS ............................................................................................................................... 41
5.3.1 Alligator Clip Type Leads..................................................................................................... 41
5.3.2 Needle Type Probes.............................................................................................................. 42
5.3.3 Surface Probes...................................................................................................................... 43
5.3.4 Other Lead Sets .................................................................................................................... 44
CHAPTER 6 REMOTE INTERFACE ............................................................................................... 45
6.1 INTRODUCTION..................................................................................................................... 45
6.2 CONNECTING THE 4176 VIA GPIB INTERFACE ............................................................... 45
6.2.1 The GPIB interface capabilities:.......................................................................................... 45
6.2.2 Notes for GPIB installation .................................................................................................. 46
6.2.3 Computer’s Connection........................................................................................................ 46
6.2.4 The GPIB connection testing................................................................................................ 46
6.3 CONNECTING THE 4176 VIA RS232 INTERFACE.............................................................. 47
6.3.1 The RS232 interface capabilities:......................................................................................... 47
6.3.2 Notes for RS232 installation................................................................................................. 47
6.3.3 Connecting to a Computer.................................................................................................... 49
6.3.4 Checking Connections .......................................................................................................... 49
6.4 INPUT AND OUTPUT QUEUE............................................................................................... 50
6.5 COMMANDS AND SYNTAX ................................................................................................. 50
6.5.1 RS232 message terminators.................................................................................................. 50
6.5.2 Entering Commands ............................................................................................................. 50
6.5.3 Command Characters........................................................................................................... 50
6.5.4 Combining Commands ......................................................................................................... 50
6.5.5 Synopsis of Commands ......................................................................................................... 51
6.6 DETAILS OF COMMAND REFERENCE............................................................................... 51
6.6.1 Command Index.................................................................................................................... 51
CHAPTER 7 BCD INTERFACE ........................................................................................................ 66
7.1 G ENERAL ................................................................................................................................... 66
7.2 BCD P IN A SSIGNMENTS ............................................................................................................. 66
CHAPTER 8 ROUTINE MAINTENANCE ....................................................................................... 69
8.1 G ENERAL ................................................................................................................................... 69
8.2 R EQUIRED T EST E QUIPMENT ...................................................................................................... 69
8.3 P RE -C ALIBRATION P ROCEDURE ................................................................................................. 69
8.4 4176 C ALIBRATION P ROCEDURE ................................................................................................ 70
8.4.1 Standard Calibration............................................................................................................ 70
8.4.2 Periodic Maintenance........................................................................................................... 75

3
CHAPTER 9 SPECIAL PROCEDURES............................................................................................ 76
9.1 N OISY R EADINGS ....................................................................................................................... 76
9.2 I NDUCTIVE L OADS ..................................................................................................................... 76
CHAPTER 10 THEORY OF OPERATION.................................................................................... 77
10.1 L OCALIZING THE P ROBLEM ........................................................................................................ 77
10.2 C OMPONENT R EPLACEMENT ...................................................................................................... 77
10.3 G ENERAL C IRCUIT D ESCRIPTIONS .............................................................................................. 78
10.4 T ROUBLESHOOTING ................................................................................................................... 79
10.5 C URRENT S OURCE D ETAILED C IRCUIT D ESCRIPTIONS ............................................................... 80
10.5.1 Power Supplies ................................................................................................................ 80
10.5.2 Constant-Current Source................................................................................................. 81
10.6 M ICRO -C ONTROLLER B OARD D ETAILED C IRCUIT D ESCRIPTIONS .............................................. 82
10.6.1 Micro-Controller ............................................................................................................. 82
10.6.2 Over-Voltage Protection.................................................................................................. 82
10.6.3 TCM................................................................................................................................. 83
10.6.4 Reset................................................................................................................................. 83
10.6.5 2.5V Reference................................................................................................................. 83
10.6.6 Download/Normal Switch................................................................................................ 83
10.6.7 RS-232/Display Switch and RS 232 Driver/Receiver....................................................... 83
CHAPTER 11 ADDENDUMS........................................................................................................... 84
CHAPTER 12 PARTS LIST ............................................................................................................. 85
CHAPTER 13 DRAWINGS AND SCHEMATICS......................................................................... 94

4
Chapter 1 . INSPECTION AND INSTALLATION
1.1 Introduction
Welcome to the world of low resistance measurement! The precision instrument you have
just purchased offers super-stable measurement capability for hard-to-test items such as
transformers, coils, shunts, and even the resistance of wire itself. Other features include
temperature compensation, hi-lo comparison and several interface options.
Please read this manual thoroughly and all accompanying addendums before attempting to
operate this ohmmeter.
1.2 Inspection
If the shipping carton is damaged, request that the carrier's agent be present when the unit is
unpacked. If the instrument appears damaged, the carrier's agent should authorize repairs
before the unit is returned to the factory. Even if the instrument appears undamaged, it may
have suffered internal damage in transit that may not be evident until the unit is operated or
tested to verify conformance with its specifications. If the unit fails to operate or fails to
meet the performance specifications of chapter 2, notify the carrier's agent and the nearest
Valhalla Sales Office. Retain the shipping carton for the carrier's inspection. DO NOT
return equipment to Valhalla Scientific, Inc. or any of its sales offices prior to obtaining
authorization to do so.
1.3 Line Voltage/Fuse Selection
The only adjustments required before placing the unit in operation are:
1. Verify that the instrument has been set for the proper local AC line voltage.
The AC line voltage is selected via a sliding switch mounted on the rear
panel of the ohmmeter.
Table 1 – Line Voltage Limits
Nominal Value (RMS) Allowable Limits (RMS)
115V 105Vac to 125Vac
230 210Vac to 250Vac