IET Labs HRRS SERIES Troubleshooting guide

PRECISION INSTRUMENTS FOR TEST AND MEASUREMENT 
IET LABS, INC.
HRRS SERIES
High Resistance
Decade Substituter
User and Service Manual
Copyright © 2017 IET Labs, Inc.
Visit www.ietlabs.com for manual revision updates
HRRS im/June 2017
www.GlobalTestSupply.com
Find Quality Products Online at: [e-mail]

PRECISION INSTRUMENTS FOR TEST AND MEASUREMENT 
IET LABS, INC.
www.GlobalTestSupply.com
Find Quality Products Online at: [e-mail]

i
HRRS Series
WARRANTY
We warrant that this product is free from defects in material and workmanship and, when properly used,
will perform in accordance with applicable IET specifications. If within one year after original shipment,
it is found not to meet this standard, it will be repaired or, at the option of IET, replaced at no charge when
returned to IET. Changes in this product not approved by IET or application of voltages or currents greater
than those allowed by the specifications shall void this warranty. IET shall not be liable for any indirect,
special, or consequential damages, even if notice has been given to the possibility of such damages.
THIS WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED OR IMPLIED,
INCLUDING BUT NOT LIMITED TO, ANY IMPLIED WARRANTY OF MERCHANTABILITY OR
FITNESS FOR ANY PARTICULAR PURPOSE.
www.GlobalTestSupply.com
Find Quality Products Online at: [e-mail]

ii
HRRS Series
WARNING
OBSERVE ALL SAFETY RULES
WHEN WORKING WITH HIGH VOLTAGES OR LINE VOLTAGES.
Dangerous voltages may be present inside this instrument. Do not open the case
Refer servicing to qualified personnel
HIGH VOLTAGES MAY BE PRESENTAT THE TERMINALS OFTHIS INSTRUMENT
WHENEVER HAZARDOUS VOLTAGES (> 45 V) ARE USED, TAKE ALL MEASURES TO
AVOID ACCIDENTAL CONTACT WITH ANY LIVE COMPONENTS.
USE MAXIMUM INSULATION AND MINIMIZE THE USE OF BARE
CONDUCTORS WHEN USING THIS INSTRUMENT.
Use extreme caution when working with bare conductors or bus bars.
WHEN WORKING WITH HIGH VOLTAGES, POST WARNING SIGNS AND
KEEP UNREQUIRED PERSONNEL SAFELY AWAY.
CAUTION
DO NOT APPLY ANY VOLTAGES OR CURRENTS TO THE TERMINALS OF THIS
INSTRUMENT IN EXCESS OF THE MAXIMUM LIMITS INDICATED ON
THE FRONT PANEL OR THE OPERATING GUIDE LABEL.
www.GlobalTestSupply.com
Find Quality Products Online at: [e-mail]

iii
HRRS Series
Table of Contents
Table of Contents
Chapter 1 Introduction
1.1 Introduction........................................................................................................... 1
Chapter 2 Specifications
2.1 Specifications ........................................................................................................ 2
2.2 Ordering Information ............................................................................................ 3
Chapter 3 Operation
3.1 Initial Inspection and Setup .................................................................................. 5
3.2 Dial Setting ........................................................................................................... 5
3.3 Environmental Conditions .................................................................................... 5
3.4 Storage .................................................................................................................. 5
Chapter 4 Maintenance
4.1 Maintainability and Reliability ............................................................................. 6
4.2 Preventive Maintenance........................................................................................ 6
4.3 Verification of Performance .................................................................................. 6
4.3.1 Calibration Interval..................................................................................... 6
4.3.2 General Considerations............................................................................... 6
4.3.3 Calibration Procedure ................................................................................. 7
4.4 Schematic.............................................................................................................. 7
4.5 Replaceable Parts .................................................................................................. 8
Figures and Tables
Figure 1-1: HRRS Series High Resistance Decade Substituter ...............1
Figure 2-1: HRRS sample label ................................................................4
Figure 4-1: HRRS Series Schematic Diagram.........................................7
Table 4-1: Replaceable Parts...................................................................8
Figure 4-2: Replaceable Parts.................................................................8
www.GlobalTestSupply.com
Find Quality Products Online at: [e-mail]

iv
HRRS Series
Table of Contents
This page is intentionally left blank.
www.GlobalTestSupply.com
Find Quality Products Online at: [e-mail]

1
HRRS Series
1Introduction
Chapter 1
INTRODUCTION
1.1 Introduction
The High Resistance Decade Substituter (HRRS
Series) is a family of instruments offering a broad
choice of high range, excellent performance resis-
tance sources (Figure 1.1). High-resistance design
is implemented with special resistors, switches,
binding posts, and construction-design to allow high
resistance performance without sacrificing other
electrical properties.
The HRRS Series employs state-of-the-art precision
resistors of various types for high accuracy, high sta-
bility, and low temperature and voltage coefficients.
The standard models offer a choice of one to seven
decades. For custom units, models up to 11 decades
are available . The panels are clearly labeled showing
the step size and maximum allowable applied input
for each decade. Higher voltage models up to >10 kV
are also available from IET Labs.
The binding posts are insulated with Kel-F high-
resistance, non-moisture-absorbing material ensure
low leakage.
With a resolution as low as 10 and a maximum
available resistance of over 1 T(= 1000 G;
= 1000 kM), the HRRS Series may be used for
exacting precision high-value resistance applications.
Steps up to 10 Tare also available from IET Labs,
Applications include calibration of meters and
megohmmeters, and checking of electrochemical
and biomedical sensors and instruments. These
instruments are useful wherever small currents and
high resistances are required, such as in testing high-
impedance amplifiers and the insulation of low-power
circuits.
The HRRS series complements the HARS series
which provides resistance steps as low as 1 m. The
units may be rack-mounted to serve as components
in measurement and control systems.
Figure 1-1: HRRS Series High Resistance
Decade Substituter
www.GlobalTestSupply.com
Find Quality Products Online at: [e-mail]

2
HRRS Series
2 Specifications
Chapter 2
SPECIFICATIONS
For convenience to the user, the pertinent specifications are given in an OPERATING GUIDE affixed to the
case of the instrument. Figure 2.1 shows a typical example.
2.1 Specifications
Resistance
per step
Total
decade
resistance
Accuracy
18-28°C; <50% RH Max voltage
per step
(V)
Maximum
voltage
(V)
Temperature
coefficient
(±ppm/°C)
Voltage
coefficient
(±ppm/V)
Stability
(±ppm/yr)
Resistor
type
Q B F
10 100 ±(0.01%+2 m) ±(0.03%+2 m) ±(0.10%+2 m) 2.5 25 15 - 10
Wirewound,
non-inductive
100 1 k±(0.01%+2 m±(0.03%+2 m) ±(0.10%+2 m) 8 80 5 - 10
1 k10 k±0.01% ±0.03% ±0.10% 23 230 5 - 10
10 k100 k±0.01% ±0.03% ±0.10% 70 700 5 - 10
100 k1 M±0.01% ±0.03% ±0.10% 230 2000 5 - 10
1 M10 M±0.01% ±0.03% ±0.10% 1000** 2000 15 <1 25
Metal-oxide
film
10 M100 M±0.03% ±0.10% ±1% 1000** 2000 15 <1 50
100 M1 G±0.10% ±0.20% ±1% 2000 2000 15 1 100
1 G10 G±0.20% ±0.50% ±1% 2000 2000 50 1 500 High-voltage
film
10 G100 G±0.50% ±1% ±1% 2000 2000 50 2 500
100 G1 T
See HRRS-5kV Series if these values are required.
1 T10 T
**To apply up to 2000 V for the first step, use the preceding decade at its “10” position. e.g. to obtain 1 MΩwith 2000 V max, set 100 kΩswitch to position “10.”
Zero resistance
<3 mper decade
Environmental conditions
Operating Conditions: 10°C to 40°C; <50% RH
Storage conditions: -40°C to 70°C
Terminals
Two five-way binding posts on 2 special, low-
leakage, Kel-F insulating sockets, and one metal
ground binding post electrically connected to the
case
Max voltage to case
2000 V peak
Mechanical:
Model Dimensions Weight
3 Decade 31.2 cm W x 8.9 cm H x 10.2 cm D
(12.3" x 3.5" x 4.0")
1.4 kg
(3.0 lb)
4-5 Decade 37.5 cm W x 8.9 cm H x 10.2 cm D
(14.8" x 3.5" x 4.0")
1.6 kg
(4.0 lb)
6-7 Decade 43.9 cm W x 8.9 cm H x 10.2 cm D
(17.3" x 3.5" x 4.0")
2 kg
(4.5 lb)
8-9 Decade 48.3 cm W x 17.8 cm H x 19.7 cm D
(19.0" x 7.0" x 7.8")
5.1 kg
(11 lb)
www.GlobalTestSupply.com
Find Quality Products Online at: [e-mail]

3
HRRS Series
3Specifications
Model Total resistance Number of
decades Resolution
HRRS-*-7-100 1.111 111 G7 100 
HRRS-*-7-1k 11.111 11 G7 1 k
HRRS-*-7-10k 111.111 1 G7 10 k
HRRS-*-8-10 1,111.111 1 M8 10 
HRRS-*-8-100 11.111 111 G8 100 
HRRS-*-8-1k 111.111 11 G8 1 k
HRRS-*-9-10 11,111.111 1 M9 10 
HRRS-*-9-100 111.111 111 G9 100 
To specify accuracy, replace * with “Q,” “B,” or “F” as required
Options
-RM: Rack mountable case for standard 19” rack
-K: Kelvin-type 4-terminal posts
-RO: Rear output
2.2 Ordering Information
Model Total resistance Number of
decades Resolution
HRRS-*-3-1M 1.11 G3 1 M
HRRS-*-3-10M 11.1 G3 10 M
HRRS-*-3-100M 111 G3 100 M
HRRS-*-4-100k 1.111 G4 100 k
HRRS-*-4-1M 11.11 G4 1 M
HRRS-*-4-10M 111.1 G4 10 M
HRRS-*-5-10k 1.111 1 G5 10 k
HRRS-*-5-100k 11.111 G5 100 k
HRRS-*-5-1M 111.11 G5 1 M
HRRS-*-6-1k 1.111 11 G6 1 k
HRRS-*-6-10k 11.111 1 G6 10 k
HRRS-*-6-100k 111.111 G6 100 k
www.GlobalTestSupply.com
Find Quality Products Online at: [e-mail]

4
HRRS Series
4 Specifications
Figure 2-1: HRRS sample label
IET LABS, INC. • Long Island, NY 11590 • Email: [e-mail] • Tel: [phone]
HRRS BLBL/01-16-2013
Observe all safety rules when working with high voltages or line voltages. Connect the (G) terminal to earth ground in order to maintain the case at a safe volt-
age. Whenever hazardous voltages (> 45 V) are used, take all measures to avoid accidental contact with any live components: a) Use maximum insulation and
minimize the use of bare conductors. b) Remove power when adjusting switches. c) Post warning signs and keep personnel safely away.
+5566(5,(6+,*+5(6,67$1&('(&$'(68%67,787(523(5$7,1**8,'(
CONSULT INSTRUCTION MANUAL FOR PROPER INSTRUMENT OPERATION
.HHSXQLWLQDVHDOHGHQYLURQPHQWZKHQQRWLQXVH 0DLQWDLQELQGLQJSRVWDUHDFOHDQIRUPLQLPXPHOHFWULFDOOHDNDJH
CAGE CODE: 62015 •www.ietlabs.com
5HVLVWDQFH
SHUVWHS
7RWDO
GHFDGH
UHVLVWDQFH
$FFXUDF\
&5+ 0D[YROWDJH
SHUVWHS
9
0D[
9ROWDJH
9
7&
SSP&
9&
SSP9
6WDELOLW\
SSP
\U
5HVLVWRU
7\SH
4% )
ȍ ȍ Pȍ Pȍ Pȍ     
:LUHZRXQG QRQLQGXFWLYH
ȍ Nȍ Pȍ Pȍ Pȍ      Nȍ Nȍ         Nȍ Nȍ         Nȍ 0ȍ         0ȍ 0ȍ         0ȍ 0ȍ         0HWDOR[LGH
¿OP
0ȍ *ȍ         *ȍ *ȍ         +LJKYROWDJH
¿OP
*ȍ *ȍ        
**To apply up to 2000 V for the first step, use the preceding decade at its "10" position. e.g. to obtain 1 M:with 2000 V max, set 100 k:switch to position "10."
=HURUHVLVWDQFH
PȍSHUGHFDGH
7HUPLQDOV
7ZR¿YHZD\ELQGLQJSRVWVRQVSHFLDOORZOHDNDJH .HO)LQVXODWLQJVRFNHWVDQGRQHPHWDOJURXQGELQGLQJ SRVWHOHFWULFDOO\FRQQHFWHGWRWKHFDVH
(QYLURQPHQWDOFRQGLWLRQV
2SHUDWLQJ&RQGLWLRQV&WR&5+ 6WRUDJHFRQGLWLRQV&WR&
0D[YROWDJHWRFDVH
9SHDN
WARNING
MODEL: HRRS-Q-2-100M
SN: B2-1306578
www.GlobalTestSupply.com
Find Quality Products Online at: [e-mail]

5
HRRS Series
5Operation
Chapter 3
OPERATION
and a setting of 10-10-10-l0-10.10 becomes:
10 1 0 0 0 0 0.0
10 1 0 0 0 0.0
10 1 0 0 0.0
10 1 0 0.0
10 1 0.0
.10 1.0
TOT 1 1 1 1 1 1.0
3.3 Environmental Conditions
For optimal accuracy, the decade box should be used
in an environment of 23°C. It should be allowed to
stabilize at that temperature after any significant
temperature variation.
Humidity should be maintained at <50% RH. This is
especially important if high resistances are involved.
3.4 Storage
If this instrument is to be stored for any lengthy period
of time, it should be sealed in plastic and stored in a
dry location. It should not be subjected to temperature
extremes beyond the specifications. Extended expo-
sure to such temperatures can result in an irreversible
change in resistance, and require recalibration.
3.1 Initial Inspection and Setup
This instrument was carefully inspected before ship-
ment. It should be in proper electrical and mechanical
order upon receipt.
An OPERATING GUIDE is attached to the case
of the instrument to provide ready reference to
specifications.
3.2 Dial Setting
Whenever the dials are used in positions 0-9, the
resulting resistance is read directly. Both the decimal
point and the steps are clearly marked on the panel.
For additional flexibility and range, each decade
provides a “10” position setting. This “10” position
on any one decade equals the “1” position on the next
higher decade. It adds about 11% to the nominal total
decade resistance.
To determine the resistance obtained when one or
more “10” settings are used, simply add “1” to the
next higher decade. For example, a setting of 3-6-
10-0-10 becomes:
3 3 0 0 0 0
6 6 0 0 0
10 1 0 0 0
0 0 0
10 1 0
TOT 3 7 0 1 0
www.GlobalTestSupply.com
Find Quality Products Online at: [e-mail]

6
HRRS Series
6 Maintenance
Chapter 4
MAINTENANCE
4.1 Maintainability and Reliability
It is possible to maintain Model HRRS indefinitely. It
is reliable due to its closed design and sealed switches
and resistors. The unit is resistant to electromagnetic
interference (EMI) because of its metal enclosure.
4.2 Preventive Maintenance
Keep the unit in a clean environment. This will help
prevent possible contamination.
The front panel should be periodically cleaned to
eliminate any leakage paths from near or around the
binding posts. To clean the front panel:
Wipe the front panel clean using alcohol and a
lint-free cloth
4.3 Verification of Performance
4.3.1 Calibration Interval
The HRRS Series instruments should be verified for
performance at a calibration interval of twelve (12)
months. This procedure may be carried out by the user
if a calibration capability is available, by IET Labs,
or by a certified calibration laboratory.
If the user should choose to perform this procedure,
then the considerations below should be observed.
4.3.2 General Considerations
It is important, whenever testing the HRRS Series
Decade Units, to be very aware of the capabilities and
limitations of the test instruments used. A resistance
bridge may be employed, and there are direct-reading
resistance meters or digital multimeters available
that can verify the accuracy of these units, especially
when used in conjunction with standards that can
serve to confirm or improve the accuracy of the test-
ing instrument
Such test instruments must have a 4:1 TUR capabil-
ity for each value calibrated. Note that the accuracy
varies for different decades.A number of commercial
bridges and meters exist that can perform this task;
consult IET Labs.
It is important to allow both the testing instrument
and the HRRS Substituter to stabilize for a number of
hours at the nominal operating temperature of 23°C,
and at nominal laboratory conditions of humidity.
There should be no temperature gradients across the
unit under test.
www.GlobalTestSupply.com
Find Quality Products Online at: [e-mail]

7
HRRS Series
7Maintenance
4.3.3 Calibration Procedure
To calibrate the HRRS unit, proceed as follows
1. Confirm that the leakage resistance between
either binding post and the case ground is
>1013.
If this is not obtained, clean the area
around the binding posts as described in
Section 4.2.
2. Confirm the zero resistance of the unit.
3. Determine the allowable upper and lower
limits for each resistance setting of each
decade based on the specified accuracy (See
Specifications on Page 2).
4. Confirm that the resistances fall within these
limits after subtraction of the zero resistance.
If any resistances fall outside thee limits,
the associated switch assembly may
require service or replacement.
WARNING
Connect the G (GND) terminal to
earth or other suitable ground in
order to maintain the case at a safe
voltage.
Whenever hazardous voltages
(>45 v) are used, take all measures to
avoid accidental contact with any live
components.
Use maximum insulation and
minimize the use of bare conductors.
REMOVE POWER WHEN ADJUSTING
SWITCHES.
Post warning signs and keep
personnel safely away.
4.4 Schematic
Refer to Figure 4-2 for a schematic of the HRRS unit.
Figure 4-1: Resistor Position on HRRS Switch
Figure 4-2: HRRS Schematic Single Decade
www.GlobalTestSupply.com
Find Quality Products Online at: [e-mail]

8
HRRS Series
8 Maintenance
4.5 Replaceable Parts
Model Ref IET Pt No Description
1 BP-1000-RD Binding Post, Red
2 BP-1000-BK Binding Post, Black
3 BP-1000-GN Binding Post, Green
4 HARS-X-4300-KNB Knob Assembly
Not Shown HARS-X-3100 Foot
Not Shown HRRS-*-SW-10 10 /step Decade Switch Assembly
Not Shown HRRS-*-SW-100 100 /step Decade Switch Assembly
Not Shown HRRS-*-SW-1k 1 k/step Decade Switch Assembly
Not Shown HRRS-*-SW-10k 10 k/step Decade Switch Assembly
Not Shown HRRS-*-SW-100k 100 k/step Decade Switch Assembly
Not Shown HRRS-*-SW-1M 1 M/step Decade Switch Assembly
Not Shown HRRS-*-SW-10M 10 M/step Decade Switch Assembly
Not Shown HRRS-*-SW-100M 100 M/step Decade Switch Assembly
Not Shown HRRS-*-SW-1G 1 G/step Decade Switch Assembly
Not Shown HRRS-*-SW-10G 10 G/step Decade Switch Assembly
To specify accuracy, replace * with “Q,” “B,” or “F” as required
Table 4-1: Replaceable Parts
Figure 4-2: Replaceable Parts
1
2
3
4
www.GlobalTestSupply.com
Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com
Find Quality Products Online at: [e-mail]