iET PRS-330 Operation Manual

♦ PRECISION INSTRUMENTS FOR TEST AND MEASUREMENT ♦

PRS-330 SERIES

Programmable

Decade Resistance Substituter

(IEEE-488.2, Ethernet and USB)

Operation Manual

IET LABS, INC.

TEL: [phone] • [phone] • FAX: [phone]

www.ietlabs.com

IET LABS, INC.

TEL: [phone] • [phone] • FAX: [phone]

www.ietlabs.com

♦ PRECISION INSTRUMENTS FOR TEST AND MEASUREMENT ♦

PRS-330 SERIES

Programmable

Decade Resistance Substituter

(IEEE-488.2, Ethernet and USB)

Operation Manual

PRS-330 IM / March 2019

IET LABS, INC.

Copyright © 2019 IET Labs, Inc.

TEL: [phone] • [phone] • FAX: [phone]

www.ietlabs.com

♦ PRECISION INSTRUMENTS FOR TEST AND MEASUREMENT ♦

IET LABS, INC.

TEL: [phone] • [phone] • FAX: [phone]

www.ietlabs.com

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 specifi cations. 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 specifi cations 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.

SAFETY PRECAUTIONS

The following general safety precautions must be observed during all phases of operation, service,
and repair of this instrument. Failure to comply with these precautions or with specifi c WARNINGS
elsewhere in this manual may impair the protection provided by the equipment. Such noncompliance
would also violate safety standards of design, manufacture, and intended use of the instrument.

IET Labs assumes no liability for the customer’s failure to comply with these precautions.

The PRS-330 complies with INSTALLATION CATEGORY I as well as POLLUTION DEGREE 2
in IEC61010-1.

If an instrument is marked CAT I (IEC Measurement Category I), or it is not marked with a
measurement category, its measurement terminals must not be connected to line-voltage mains.

The PRS-330 is an indoor use product.

DANGEROUS PROCEDURE WARNINGS
Comply with all WARNINGS - Procedures throughout in this manual and instructions on the
instrument prevent you from potential hazard. These instructions contained in the warnings must
be followed.

BEFORE APPLYING POWER
Verify that all safety precautions are taken. Make all connections to the instrument before applying
power. Note the instrument’s external markings described under “Safety Symbols”.

GROUND THE INSTRUMENT
This is a Safety Class I instrument. To minimize shock hazard, the instrument chassis and cabinet
must be connected to an electrical ground. The power terminal and the power cable must meet
International Electrotechnical Commission (IEC) safety standards.

SAFETY PRECAUTIONS CONTINUED

CAUTION

• DO NOT Operate in an Explosive Atmosphere

• Do not operate the instrument in the presence of infl ammable gasses or fumes

• Operation of any electrical instrument in such an environment clearly constitutes a safety hazard

• Use Caution around live circuits and whenever hazardous voltages > 45 V are present

• Operators must not remove instrument covers

• Component replacement and internal adjustments must be made by qualifi ed maintenance
personnel only

• DO NOT substitute parts or modify the instrument

• When working with high voltages; post warning signs, train personnel and keep unauthorized personnel
away.

Do not apply any voltage or currents to the terminals of the instrument in excess of the maximum limits
indicated in the specifi cations section of this manual.

To avoid the danger of introducing additional hazards, do not install substitute parts or perform unauthorized
modifi cations to the instrument.

Return the instrument to an IET Labs for service and repair to ensure that safety features are maintained
in operational condition.

Safety Symbols

General defi nitions of safety symbols used on the instrument or in manuals are listed below.

Caution symbol: the product is marked with this symbol when it is necessary for the user to
refer to the instruction manual.

Hazardous voltage symbol: the product is marked with this symbol when high voltage maybe
present on the product and an electrical shock hazard can exist.

Indicates the grounding protect terminal, which is used to prevent electric shock from the
leakage on chassis. The ground terminal must connect to earth before using the product

Direct current.

Alternating current.

Frame or chassis terminal. A connection to the frame (chassis) of the equipment which
normally includes all exposed metal structures.

On supply.

Off supply.

Hot surface. Avoid contact. Surfaces are hot and may cause personal injury if touched.

Disposal

Waste Electrical and Electronic Equipment (WEEE) Directive 2002/96/EC
This product complies with the WEEE Directive (2002/96/EC) marking requirements.
The affi xed label indicates that you must not discard this electrical/ electronic product in domestic
household waste.
Product Category: With reference to the equipment types in the WEEE directive Annex 1, this product
is classifi ed as a “Monitoring and Control instrumentation” product.

Do not dispose of electrical appliances as unsorted municipal waste, use separate collection facilities.

Contact your local government for information regarding the collection systems available. If electrical
appliances are disposed of in landfi lls or dumps, hazardous substances can leak into the groundwater
and get into the food chain, damaging your health and well-being.

When replacing old appliances with new one, the retailer is legally obligated to take back your old ap­pliances for disposal.

Proposition 65 Warning for California Residents

WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov.

This product may contain chemicals known to the State of California to cause cancer, birth defects, or
other reproductive harm

PRS-330 Series

CONTENTS

WARRANTY ........................................................................................................... i

WARNING .............................................................................................................ii

CAUTION ..............................................................................................................ii

CONTENTS .......................................................................................................... iii

Chapter 1: INTRODUCTION ................................................................................ 1

Chapter 2: SPECIFICATIONS .............................................................................. 3

2.1 Specifi cations .................................................................................................................3

2.2 General Specifi cations and Stability ..............................................................................4

2.2 Typical Label ..................................................................................................................5

Chapter 3: OPERATION ....................................................................................... 7

3.1 Initial inspection and setup ............................................................................................7

3.1.2 Purpose .................................................................................................................7

3.1.3 Storage ..................................................................................................................7

3.1.4 Bench and Rack Setup ..........................................................................................7

3.1.5 Front and Rear Panel ............................................................................................7

3.1.6 Power Connections ...............................................................................................8

3.1.7 Environmental ......................................................................................................8

3.1.8 Safety Considerations ...........................................................................................8

3.1.9 Cleaning ................................................................................................................9

3.2 Connection .....................................................................................................................9

3.2.1 General Considerations ........................................................................................9

3.2.2 Electrical Considerations ......................................................................................9

3.3 Condensed Operating Instructions ...............................................................................10

3.4 Menu Structure .............................................................................................................11

3.4.1 Home Screen ......................................................................................................15

3.4.2 Setting a Resistance Value ..................................................................................15

3.4.3 Menu Key ...........................................................................................................15

3.4.4 Resistance Settings Menu ...................................................................................15

3.4.5 Standard Values Menu ........................................................................................16

3.4.5.1 Set Values ..................................................................................................16

3.4.5.2 Standard Value ..........................................................................................17

3.4.5.3 Decade Value ............................................................................................17

3.4.5.4 Percent Value ............................................................................................17

3.4.6 RTD and Other Tables Menu ..............................................................................18

3.4.6.1 User Select RTD Menu .............................................................................19

3.4.7 Remote Communications Settings Menu ..........................................................19

3.4.7.1 IEEE Interface Menu .................................................................................20

3.4.7.2 Ethernet Interface Menu ............................................................................20

3.4.8 About Menu ........................................................................................................20

3.5 Thermal emf Considerations .................................................................................21

3.6 Environmental Conditions .....................................................................................21

iiTable of Contents

3.7 Remote Operation ..................................................................................................21

Chapter 4: USB Interface .................................................................................. 22

4.1 Introduction ..................................................................................................................22

4.2 Capabilities ..................................................................................................................22

4.3 USB Operation .............................................................................................................22

4.3.1 USB Interface Drivers ........................................................................................22

Chapter 5: ETHERNET INTERFACE .................................................................23

5.1 Ethernet Programming .................................................................................................23

5.2 Network Setup .............................................................................................................23

5.3 Ethernet Test Keyboard ................................................................................................23

5.4 Network Confi guration ................................................................................................24

5.5 Web Browser Confi guration .........................................................................................25

5.6 VXI Confi guration Utility ............................................................................................26

5.7 Resetting Default Network Settings .............................................................................28

PRS-330 Series

Chapter 6: IEEE INTERFACE ............................................................................. 29

6.1 Introduction ..................................................................................................................29

6.2 Capabilities ..................................................................................................................29

6.3 Address Switch and Communications Settings ............................................................29

6.4 IEEE Option Operation ................................................................................................29

Chapter 7: PROGRAMMING ................................................................... 31

7.1 Introduction ......................................................................................... 31

Chapter 8: MAINTENANCE .................................................................... 33

8.1 Verifi cation of Performance .................................................................... 33

8.1.1 Calibration Interval ........................................................................ 33

8.1.2 General Considerations .................................................................. 33

8.1.3 Calibration Procedure .................................................................... 33

8.1.4 Adjustment of Internal Resistors ..................................................... 34

8.1.5 Calibration Menu and Process ......................................................... 35

8.1.6 Full Calibration (adjustment) .......................................................... 35

8.1.7 Calibration History ........................................................................ 36

8.2 Replaceable Parts List ........................................................................... 35

Chapter 9: PRS-DMM Self Adjusting Software .................................... 39

9.1 PRS-DMM Self Adjusting Softtware ....................................................... 39

9.1.1 Overview ...................................................................................... 39

9.1.2 General Requirements .................................................................... 39

9.1.3 Software Installation ...................................................................... 39

9.1.4 Connection Between DMM and PRS-330 ........................................ 39

iii Table of Contents

PRS-330 Series

9.1.5 PC Connection Between DMM and PRS-330 ................................... 40

9.2 PRS-DMM Main Screen ........................................................................ 40

9.2.1 PRS-DMM Main Screen Operation ................................................. 40

9.3 PRS-DMM Settings ............................................................................... 40

9.3.1 PRS-DMM Settings Screen ............................................................ 40

9.3.2 PRS Settings ................................................................................. 40

9.3.3 Meter Settings ............................................................................... 41

9.3.4 Adjust PRS ................................................................................... 42

9.3.5 PRS-DMM Speed .......................................................................... 42

APPENDIX A: SCPI COMMAND REFERENCE ...................................... 44

APPENDIX B: IEEE.2 COMMON COMMANDS ...................................... 47

ivTable of Contents

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PRS-330 Series

Table of Contents

v

PRS-330 Series

Chapter 1

INTRODUCTION

The PRS-330 (Figure 1.1) is a high
precision manual and programmable decade
substituter. The PRS-330 series provide
direct resistance substitution as well as RTD
(Resistance Temperature Detector) simulation.

The PRS-330 substituter is a precision
resistance source with excellent characteristics
of stability, temperature coeffi cient, and power
coefficient. These features combined with
a low virtually constant “zero resistance”
make for very versatile instruments.

Operation is both local using convenient
touch screen, keypad and standard USB,
Ethernet, and IEEE-488.2 interfaces.

The PRS-330 employs very low resistance,
low thermal emf relays with gold-clad silver­alloy contacts. A special design keeps contact
resistance to a minimum. The gold plating keeps
the silver contacts from becoming tarnished
when unused, or when only low currents are
passed through them. This is most often the
case when only minute test currents are drawn
by digital multimeters and other test instruments.
Contact resistance remains low and repeatable.

maximum available resistance of 20 MΩ, the
PRS-330 may be used for exacting precision
measurement applications requiring high
accuracy, good stability, and low zero resistance.

The PRS-330 is suited for automatic and
manual calibration and testing, simulation
of RTD’s, programmable loads, and many
other laboratory and industrial applications.

The PRS Series may be rack mounted to serve as
components in measurement and control systems.

The PRS-330 (Figure 1.1) is part of the
PRS family of high precision manual and
programmable decade substituters. This
series offers a wide choice of ranges, power,
voltage, and accuracies for a wide variety
of design and production applications.

The PRS-330 uses a microcontroller design to
enhance the ease of use and calibration. It provides

High-quality gold-plated tellurium-copper
fi ve-way binding posts serve to minimize the
thermal emf effects, which would produce
errors in dc resistance measurements.

With a resolution as low as 1 μΩ and a

INTRODUCTION

Figure 1.1: High Precision Programmable Decade

Resistance Substituter

1

PRS-330 Series

direct resistance substitution as well as RTD
(Resistance Temperature Detector) simulation. It
allows for higher precision and tight tolerances.

The PRS-330 is a precision resistance source
with excellent characteristics of accuracy,
stability, temperature coeffi cient, and power
coeffi cient. It is direct reading without
the need to subtract “zero resistance.”

The PRS-330 offers the option of true
4-wire Kelvin measurement for calibration
applications and 2-wire mode for use
in series as a substitute resistor and for
RTD applications. The front panel display
indicates the mode selected: 2-wire or 4-wire.

There are 4 pre-programmed RTD
resistance tables, and others may be added
by the user. The controller allows for
other convenient programmed features.

Fluke 8508A or Keysight 3458A to automate
this adjustment process and eliminate the
need for a technician to manual enter the
resistance values manually into the PRS­330 See Chapter 9 for more information

The unique design makes adjustment of the
PRS-330 for calibration semiautomatic. An
internal calibration routine guides the user to
perform measurements using only a precision
ohmmeter and enter the measured values into
the PRS-330. No other standards are required.

IET Labs offers the PRS-DMM Self Adjusting
Software which works with the PRS-330 and

2

INTRODUCTION

PRS-330 Series

Chapter 2

SPECIFICATIONS

For convenience to the user, the pertinent
specifi cations are given in an OPERATING
GUIDE, shown typically in Figure 2.1, affi xed
to the case of the instrument.

2.1 Specifi cations

User interface:

Numeric keypad, softkeys and color capacitive touch
screen

Accuracy:

±(70 ppm + 1 m) 2 and 4 Terminal at 23°C ±5°C

Minimum setting: 0.100 000 
Resolution: 1  or 6 digits
Range: 0.1  - 20 M
Stability: ±50 ppm/year
Thermal emf: <15 V
Resistance difference front to rear binding

posts:

±(2 ppm + 20 )
Maximum load: 2 A, 200 V (peak), 0.5 W whichever

applies fi rst

Resistors: Precision wire-wound and metal foil
TC of resistors: <1 ppm/°C for 1.37  and above
Relays1: Silver Alloy contacts, expected life of 10

cycles

Switching time: <10ms second per change
RTD simulation:

9 RTD tables can be entered into memory to allow
user selection of temperature and the correct value
of resistance will automatically be programmed.

PT-100 and PT-1000 tables for both Fahrenheit and
Celsius are pre-programmed into memory locations
1 to 4.

Adjustment:

Automatic adjustment procedure utilizing a high pre­cision DMM eliminates the requirement for manual
trimming of resistors.

Terminals:

Front and rear connections each consisting of 4
low-emf, gold-plated, tellurium-cop per 5-way bind ing

posts are used for HI and LO ter mi nal pairs for CUR-
RENT and SENSE. GND bind ing post is con nect ed

to the case, to chassis ground.

ac frequency response:

Residual capacitance terminals to GND: < 850 pF

Resistance Typical ac/dc difference @ 1 kHz

0.1  -10 k <100 ppm

10 - 100 k <200 ppm

100 k - 1 M <1%

1 - 20 M <20%

Power requirements:

90 - 264 Vac , 47 - 63 Hz., 30 W. Max.

Fuse: T 0.8 A, 250 V, 5 x 20 mm

Environmental conditions:

Operating: 10°C to 40°C;

<80% RH non-condensing

Storage: -40°C to 70°C ; <90% RH

non-condensing

Remote control:

USB: USB Type B connector standard on rear

panel; uses standard MCP2200 chip set

GPIB:

8

GPIB standard 24 pin connector, conforms to IEEE-

488.2; SCPI 1994.0 command set; Hardware or
software confi gurable addressing range of 1 to 30.

Ethernet:

IEEE 802.3 compliant, Speeds 10 BaseT
(10 Mb/s) and 100 BaseT (100 Mb/s), IP Address
Static or DHCP, Factory setting 192.168.0.254
static

Dimensions:

Bench model: 43 cm W x 8.9 cm H x 33 cm D
(17” x 3.5” x 13”) in front of panel: 3.8 cm (1.5”)
Rack Mount: 47 cm W x 8.9 cm H x 33 cm D
(19” x 3.5” x 13”) in front of panel: 3.8 cm (1.5”)

Weight:

Bench model: 5.5 kg (12 lb) nominal

1

Note: Warranty covers relays up to expected life

SPECIFICATIONS

3

PRS-330 Series

2.2 General Specifi cations and Stability

Warm-up:

This unit utilizes custom designed low thermal
emf relays for high stability and low-level signal
applications. This thermal voltage is nominally
less than 15 μV under laboratory conditions.
Please note that a change in this thermal emf will
give a false drift in resistance as measured by a
dc ohmmeter, since the ohmmeter will interpret
this emf as an effective resistance. The worst
case such effective drift after warm-up is less than
±25 ppm, primarily due to stabilization of this
emf at the relay contacts as settings are changed.

Unit should be allowed to stabilize for
one hour. For maximum stability, allow
unit to warm-up over two hours.

Recommended Calibration Interval:

Typical calibration interval 12 months.
Adjustment can easily and automatically be
accomplished using IET’s PRS-DMM software
Adjusting the PRS-330 can improve accuracy
associated with the drift of the resistors.

Short-term Stability:

The PRS-330 was tested for extended periods
of time. Based upon this testing the following
stability information was determined. These
specifications apply for the PRS-330 in 4
terminal mode with shorting links removed
and without switching to another value.

Typical short-term stability without
switching:

< ±(4 ppm + 100 μΩ) / 10 minutes

Typical 24 hr. Accuracy after Adjustment:

After performing an adjustment per 8.1.4
of this manual using a Fluke 8508A and
then performing a calibration verifi cation per

8.1.3 within 24 hours the typical accuracy is:

±(30 ppm + 300 μΩ) for values <1 MΩ
±60 ppm for values > 1 MΩ

See graph below for actual performance,
shown in blue, with 6 digit resolution
across resistance range. The red lines
represent tolerance of ±(30 ppm + 300 μΩ).

Environmental:

This product complies with the
WEEE Directive (2002/96/EC)
marking requirements. The affixed
label indicates that you must not
discard this electrical/electronic
product in domestic household waste.

Product Category: With reference to the
equipment types in the WEEE Directive Annex
I, this product is classed as a “Monitoring
and Control instrumentation” product.

Effects of Humidity:

Exposure to humidity >60% for a periods of weeks
can cause the resistors to drift some of that is
reversible. It is recommended that the PRS-330 be
stored at humidities less than 50% to minimize this.

Figure 2-1 Error versus Resistance up to 1 MΩ

4

SPECIFICATIONS

PRS-330 Series

PRS-330 PROGRAMMABLE DECADE RESISTANCE SUBSTITUTER

CONSULT INSTRUCTION MANUAL FOR PROPER INSTRUMENT OPERATION

Accuracy: ±(0.007% + 1 m) 2 and 4 Terminal at 23°C ±5°C
Minimum setting: 0.100 000 
Resolution: 1  or 6 digits
Stability: ±50 ppm/year
Range: 0.1  - 20 M
Thermal emf: <15 V
Maximum Load: 2 A, 200 V (peak), 0.5 W whichever applies fi rst
Resistors: Precision wire-wound and metal foil
RTD Tables:

PT-100 and PT-1000 tables for both Fahrenheit and Celsius are programmed
into memory locations.

9 RTD tables can be entered into memory to allow user selection of temperature
and the correct value of resistance will automatically be programmed.

Adjustment:

Automatic adjustment procedure utilizing a high precision DMM eliminates the
requirement for manual trimming of resistors.

1

Relays

: Silver Alloy contacts, expected life of 10

Observe all safety rules when working with high voltages or line voltages. Connect the (GND) terminal to earth 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: a) Use maximum insulation and minimize the use

IET LABS, INC.

CAGE CODE: 62015

of bare conductors. b) Remove power when adjusting switches. c) Post warning signs and keep personnel safely away.

8

cycles

• Long Island, New York

• Tel: [phone] • Email: [email protected]

Terminals:
Four low-emf, gold-plated, tellurium-cop per 5-way bind ing posts are used for HI

and LO ter mi nal pairs for CUR RENT and SENSE. GND bind ing post is con nect ed
to the case, to the chassis ground and to the earth ground.

Switching time: <1 second per change
Power requirements:

90 - 264 Vac , 47 - 63 Hz. 30 W. Max.

Remote Control:
USB: Standard USB Type B connector on rear panel, uses MCP2200 driver

Remote Control Options:
IEEE: GPIB standard 24 pin connector, conforms to IEEE-488.2; SCPI 1994.0

command set; Hardware or software confi gurable addressing range of 1 to 30.
Ethernet: IEEE 802.3 compliant, Speeds 10 BaseT

(10 Mb/s) and 100 BaseT (100 Mb/s), IP Address Static or DHCP, Factory setting

192.168.0.254 static

1

Note: Warranty covers relays up to expected life

MODEL: PRS-330 SN: B2-18431158

WARNING

www.ietlabs.com

PRS-330 Nov. 2018

SPECIFICATIONS

FIGURE 2.1 Typical OPERATING GUIDE Affi xed to Unit

(Please see label affi xed to your unit)

5

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PRS-330 Series

6

SPECIFICATIONS

PRS-330 Series

Chapter 3

OPERATION

3.1 Initial inspection and setup

This instrument was tested and carefully
inspected before shipment. 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
specifi cations.

3.1.2 Purpose

The purpose of the PRS-330 is to source
resistance in the range of 0.1 Ω to 20 MΩ for
calibration of DMMs, meters and use as an RTD
Simulator.

3.1.3 Storage

Mount the unit in a standard 19” rack if the rack
mount option is specifi ed.

3.1.5 Front and Rear Panel

The front panel has a capacitive touchscreen,
front binding posts, softkeys, numeric keypad
and power switch.

3

1

2

Front Panel

4

5

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 specifi ca-
tions. Extended exposure to such temperatures
can result in an irreversible change in resistance,
and require recalibration.

3.1.4 Bench and Rack Setup

The PRS-330 should be placed on a stable fl at
work surface. A front bail is provide to make
viewing easier.

OPERATION

Model Ref. Description
1 Front Binding Posts
2 Capacitive Touchscreen
3 Softkeys
4 Numeric Keypad
5 Power Switch

7

The rear panel has an IEC inlet module for con­nection to mains power, GPIB, USB and Ethernet
interfaces and rear binding posts.

1

2

3

PRS-330 Series

Power requirements:

90 - 264 Vac , 47 - 63 Hz., 30 W. Max.

Fuse

Only replace fuse with the same type and rat­ing.

UL/CSA type, T 0.8 A,250 V, 5 x 20 mm

3.1.7 Environmental

Do not operate the instrument in the presence
of fl ammable gasses or fumes.

Rear Panel

Model

Description

Ref.
1 IET Inlet Module
2 GPIB, USB and LAN Interfaces
3 Rear Binding Posts

3.1.6 Power Connections

Power connection to the rear panel is through
an ac inlet module comprised of an ac connector
and fuse drawer.

Always use an power cord and outlet that has a
properly connected protection ground to avoid
shock. The PRS-330 is provided with a 3-prong
power cord with ground.

The PRS-330 is for indoor use only.

To ensure that the safety requirements, the speci­fi cations, and the measurement accuracy of the
PRS-330 are met, you must maintain the environ­mental temperature to within the specifi ed range
by providing an appropriate cooling clearance
around the PRS-330 or, for the rack-mounted
type, by forcefully air-cooling inside the rack
housing, if necessary.

Temperature and Humidity

Operating: 10°C to 40°C; <80% RH

non-condensing
Storage: -40°C to 70°C ; <90% RH
non-condensing

Altitude

Operating: 0 - 2000 m; storage: 0 - 4600 m

Plug the supplied IEC power cord into the instru­ment into a power receptacle that has a ground.
The power cord may of course be selected to
match the available receptacle.

Confi rm that the power supplied to the PRS-
330 meets the following requirements

8

3.1.8 Safety Considerations

Refer to the Safety Summary page at the begin­ning of this guide for general safety informa­tion. Before installation or operation, review
this guide for safety warnings and instructions.
Safety warnings for specifi c procedures are
located at appropriate places throughout this

OPERATION

PRS-330 Series

guide.

There are no user serviceable parts inside the
PRS-330. Servicing should be referred to qual­ifi ed personnel.

3.1.9 Cleaning

To prevent shock unplug the PRS-330 from mains
prior to cleaning.

Use a dry cloth or a cloth slightly dampened with
water to clean the external case parts.

Do not use detergents or chemical solvents.

Do not attempt to clean internally.

Denatured alcohol can be used to clean insula-

tors around binding posts.

binding posts of the PRS-330 when set to 2 Wire.
See section 3.4.4 for more information

The GND terminal on all models is connected to
the case and to earth and chassis grounds. This
may be used as a shield terminal.

3.2.2 Electrical Considerations

The performance of the PRS-330 is directly
affected by the quality of the connection to
the system under test. This is particularly true
with the precision series models having higher­accuracy and/or lower-impedance decades.

For optimum performance, contact resistance
should be kept to a minimum by using the most
substantial mating connection possible, and by
assuring that the connection is well secured to
the binding posts.

3.2 Connection

3.2.1 General Considerations

The PRS-330 Programmable Decade Resistance
Substituter utilizes a 5-terminal connection. The
binding posts are standard laboratory type and
readily accept banana plugs, spade lugs, alligator
clips, and bare wire. Binding posts are located on
the front panel and rear panel of the instrument.

The Kelvin terminals consisting of a CURRENT
and a SENSE pair, each labeled HI and LO.
These minimize contact resistance.
4 Wire connection
The gold shorting links must be removed on the
binding posts of the PRS-330 when set to 4 Wire.

2 Wire connection

The gold shorting links must be used on the

Condensed Operating Instructions

3.3

1. Turn on the PRS-330 ON using POWER
SWITCH

2. From the Home screen, select a desired
resistance value in one of the following ways:

a) Enter a value using the number keys, then
press ENTER.
b) Press the resistance value shown on the
touch screen and then enter the resistance
value using the touch screen or keypad.

3. The source resistance will be output to the
front or rear binding posts and is indicated at on
the bottom half of the Home screen. Front and
rear binding posts can be selected by going to
Main Menu>Resistance Settings.

4. 2-Wire or 4-Wire connection mode is shown
at the top of the Home screen. This can be
changed by going to Main Menu>Resistance
Settings.

OPERATION

9

PRS-330 Series

3.4 Menu Structure

The tables on the next few pages shows the menu
structure of the PRS-330.
Menu items with a “:” allow selection of a value
or feature when ENTER pressed. Menu items
without “:” have a submenu with more than 1
item.
Press MENU to display Main Menu and press
the Back key to return to Home screen.

Below is the basic menu structure of the PRS-

330.

3.2 Connection

3.2.1 General Considerations

The PRS-330 Programmable Decade Resistance
Substituter utilizes a 5-terminal connection. The
binding posts are standard laboratory type and
readily accept banana plugs, spade lugs, alligator
clips, and bare wire. Binding posts are located on
the front panel and rear panel of the instrument.

The Kelvin terminals consisting of a CURRENT
and a SENSE pair, each labeled HI and LO.
These minimize contact resistance.

4 Wire connection
The gold shorting links must be removed on the
binding posts of the PRS-330 when set to 4 Wire.

2 Wire connection

The gold shorting links must be used on the
binding posts of the PRS-330 when set to 2 Wire.
See section 3.4.4 for more information

3.2.2 Electrical Considerations

The performance of the PRS-330 is directly
affected by the quality of the connection to
the system under test. This is particularly true
with the precision series models having higher­accuracy and/or lower-impedance decades.

For optimum performance, contact resistance
should be kept to a minimum by using the most
substantial mating connection possible, and by
assuring that the connection is well secured to
the binding posts.

3.3

Condensed Operating Instructions

1. Turn on the PRS-330 ON using POWER
SWITCH

2. From the Home screen, select a desired
resistance value in one of the following ways:

a) Enter a value using the number keys, then
press ENTER.
b) Press the resistance value shown on the
touch screen and then enter the resistance
value using the touch screen or keypad.

3. The source resistance will be output to the
front or rear binding posts and is indicated at on
the bottom half of the Home screen. Front and
rear binding posts can be selected by going to
Main Menu>Resistance Settings.

4. 2-Wire or 4-Wire connection mode is shown
at the top of the Home screen. This can be
changed by going to Main Menu>Resistance
Settings.

The GND terminal on all models is connected to
the case and to earth and chassis grounds. This
may be used as a shield terminal.

10

OPERATION

PRS-330 Series

3.4 Menu Structure

The tables on the next few pages shows the menu
structure of the PRS-330.
Menu items with a “:” allow selection of a value
or feature when ENTER pressed. Menu items
without “:” have a submenu with more than 1
item.
Press MENU to display Main Menu and press
the Back key to return to Home screen.

Below is the basic menu structure of the PRS-

330.

OPERATION

11

PRS-330

PRS-330 Series

Main

Menu

Resistance Settings
Remote Communication Settings

Instrument Calibration (only shown when Cal Enable pressed)

About

Main

Menu

Main

Menu

Main

Menu

Resistance

Settings

Connection Mode: 4-Wire or 2 Wire
Terminal Selection: Front or Rear

Standard Values
RTD and Other Tables Settings

Switch Mode: Fast or Slow

Resistance

Settings

Resistance

Settings

Standard

Values

*Set Value: 0.1 ȍ
Standard Value:1%
Decade Value: 0.1 ȍ
Percent Value: 0.001%

Table

Settings

Main

Menu

12

*Probe Type: None, PT-100 °C, PT-100 °F, PT-1000
°C, PT-1000 °F, or Default

User Selected RTD

Resistance

Settings

Table

Settings

User Function: Default
Units: °F, °C, K

Main Menu>Resistance Settings

User

Selected

OPERATION

PRS-330 Series

PRS-330

Resistance Settings
Remote Communication Settings

Instrument Calibration (only shown when Cal Enable pressed)

About

Main

Menu

Main

Menu

Main

Menu

Main

Menu

Remote

Communication

Settings

IEEE
Ethernet

Remote

Communication

Settings

Remote

Communication

Settings

IEEE

IEEE Address: 1 - 30

Ethernet

IP Address: 192.168.100.101
Network Gateway: 192.168.100.1
Network Mask: 255.255.255.0
Mac Address: 00:00:00:00:00:00

OPERATION

Main Menu>Remote Settings

13

PRS-330 Series

Main

Menu

Main

Menu

Instrument
Calibration

Full Calibration <Enter Password>
Trace Calibration <Enter Password>
Calibration History

Instrument
Calibration

Calibration

History

Calibrated Resistor: <R1 – R43>

Main Menu>Calibration

PRS-330

Main

Menu

Resistance Settings
Remote Communication Settings

Instrument Calibration (only shown when Cal Enable pressed)

About

Main

Menu

About

IET Labs, Inc.
PRS-330
SN: XX-XXXXXXXX
FW: 1.15
HW: 1.00
Reset to Default <Yes or No>
Factory Reset <Yes or No>

Main Menu>About

14

OPERATION

PRS-330 Series

3.4.1 Home Screen

The home screen shows the resistance value in
ohms or temperature if RTD tables are used.
The main display also shows if the unit is
confi gured for 4-wire mode or 2-wire mode in the
upper left corner of the display after Resistance.

Figure 3-1 Home screen showing 2-Wire

See section 3.2.1 for more information on 2-wire
and 4-wire connections.

of the value via the touch screen. During entry
you can use softkeys to select Ω, kΩ or MΩ.

3.4.3 Menu Key

Pressing the MENU key will show the MAIN
menu screen See Figure 3-2

Figure 3-2 Menu Screen

Use the key to move UP and the to move
DOWN within the items shown on screen.

Pressing MENU will display the main menu
Pressing INC or DEC will increment or
decrement the resistance value based upon
Resistance Settings>Standard Values. This
allows increasing or decrement the resistance
value by a percentage, value in Ωs decade value
or EIA preferred values.

Pressing the LOCAL key will switch from
Remote control to local control.

The bottom part of the home screen shows
relevant setup information. These settings can be
changed in the Resistance Settings menu.

3.4.2 Setting a Resistance Value

To set a resistance value use the numeric keypad
to enter the value followed by the ENTER key.
Pressing the resistance or temperature value
shown on the Home screen will also allow entry

Press the ENTER key to change the item’s value
or go to the next menu.

Press the BACK key to return to previous MENU
or home screen at anytime.

3.4.4 Resistance Settings Menu

Using the UP and DOWN arrow keys
RESISTANCE SETTINGS can be highlighted
in yellow, press the ENTER key to go to the
RESISTANCE SETTINGS menu.

Breadcrumb navigation shown at the top of the
screen shows exactly where you are in the menu
system.

OPERATION

15

Figure 3-3 Resistance Settings Menu

There are 5 selections available in the
RESISTANCE SETTINGS menu.

Highlight the selection and press ENTER to
change the selection.

Connection Mode: allows the user to change
between 2-Wire and 4-Wire connections.

In 2-Wire the shorting links should be connected
between the two LO terminals, and between the
two HI terminals.

In 2-Wire mode the internal trace resistance
inside the PRS-330 is automatically compensated
for, so no zero subtraction is required.

PRS-330 Series

between previous value and the new value will
either be a SHORT, OPEN or undetermined in
default switching case.

Standard Values and RTD and Other Tables
Settings have separate menus which are

described in the sections below.

3.4.5 Standard Values Menu

There are 4 selections available in the STANDARD
VALUES menu. The STANDARD VALUES

menu is only applicable to resistance values and
not RTD or Tables.

The selection of the standard values controls how
the INC and DEC softkeys work on the Home
screen see Figure 3-1.

When a value is entered into one of the 4
selections such as Percent Value: shown in Figure
3-4 the INC and DEC keys will then in this
example increment or decrement the resistance
value by 10% each time the key is pressed.
An * before the selection indicates which is
active. The last selection to which a value was
entered becomes the active selection.

In 4-Wire mode shorting links should be removed
from the binding posts. This mode was designed
to be used with DMMs, other meters with 4
terminal (Kelvin connections) and temperature
controllers and indicator using 4 terminal RTDs.

Terminal Selection: allows selection of either
rear binding posts or front binding posts to be
connected to the source resistance.

There is no signifi cant difference in accuracy

Switch Mode: Allows selection of Default,
Open or Short modes. When the resistance or
temperature value is changed via the front panel
or when a SOURCE:DATA command is sent
via the remote interfaces, the intermediate value

16

3.4.5.1 Set Values

The Set Value: selection allows the resistance
value to be changed by a specifi c value in Ωs each
time the INC, increment, and DEC, decrement,
key is pressed.

Highlight Set Value: and press ENTER to
change the set value.

When a Set Value: is selected on the PRS-
330 pressing the INC and DEC softkeys will
increment the resistance value to the next
resistance value plus or minus the Set Value.

3.4.5.2 Standard Value

OPERATION

PRS-330 Series

The Standard Value: allows the PRS-330 to be
used as an automated resistance carousel with
built-in EIA “preferred value” resistance tables
of 1% (E96), 5% (E24), 10% (E12) increments
or RATIOMETRIC user specifi ed increment.

Figure 3-4 Standard Values Menu

Resistors are available in a number of standard
ranges, often called ‘preferred values’ These
ranges, or series, are set out by the Electronic
Industries Association (EIA), and common
values are E12, E24, E48, and E96. The number
after the ‘E’ denotes the number of resistance
values the series contains per decade.

0.8% but can be set to the required value in %.

The series are logarithmic and are derived from
the resistor tolerance; resistors with a tighter
tolerance can have more values in the series
that won’t overlap one another. The series are
sometimes referred to by the tolerance, the two
being related as follows:

E12: 10% tolerance
E24: 5% tolerance
E48: 2% tolerance
E96: 1% tolerance

When a Standard Value: is selected on the
PRS-330 pressing the INC and DEC softkeys
will increment the resistance value to the next
“preferred” resistance value.

RATIOMETRIC allows a custom tolerance value
to be entered by the user. The default value is

OPERATION

17

PRS-330 Series

3.4.5.3 Decade Value

The Decade Value: selection allows the resistance
value to increment by a decade value in Ωs each
time the INC and DEC key is pressed.

Highlight Decade Value: and then press the
ENTER key to show the pull-down menu
where decade values from 0.1 Ω to 10 MΩ can
be selected.

When a Decade Value: is selected on the PRS-
330 pressing the INC and DEC softkeys will
increment the resistance value to the next decade
resistance value.

3.4.5.4 Percent Value

The Percentage Value: selection allows the
resistance value to increment or decrement by a
specifi c percentage from 0.0001% to 10% each
time the INC and DEC key is pressed.

Highlight Percentage Value: and press ENTER
to change the set value.

When a Percentage Value: is selected on the
PRS-330 pressing the INC and DEC softkeys
will change the resistance value to the resistance
value plus the resistance value multipled by the

Percentage Value:.

3.4.6 RTD and Other Tables Menu

to change between the various RTD tables.

Select None for no RTD table and resistance in
Ωs will be displayed.

Selecting other tables the units will change to °C
, °F , °K depending upon the table being selected.

DEFAULT is a user defined table and is
confi gured as outlined in section 3.4.5.1.

Figure 3-4 No RTD or Table

Press the ENTER key and then use the

key to

move UP and the to move DOWN within the
items shown on screen, see Figure 3-5., to select
the desired |RTD table to be used. For example

pressing the ENTER key and using the

key to

move UP and the to move DOWN to highligh
PT-100 °C and then pressing the ENTER key
will select use of the PT-100 °C table as shown
in Figure 3-5

Selecting the RTD and Other Tables menu
allows use of tables.

There are 9 tables that can be selected. The fi rst
4 tables, are defi ned as PT-100 °C, PT-100 °F,
PT-1000 °C and PT-1000 °F where C is degrees
Celsius and F is degrees Fahrenheit.

Press ENTER when Probe Type: is highlighted

18

Figure 3-5 Select RTD

OPERATION

PRS-330 Series

Once the table is selected the home screen will
change for example to temperature on the display
see Figure 3-6.

Figure 3-6 PT-100 °C set to 100 °C

3.4.6.1 User Select RTD Menu

Figure 3-8 Select Table Name

Pressing ADD key opens an entry screen so that
a name of the table can be entered.
If there are tables which need to be deleted then
highlight the table and press DEL.
Once the table name is entered, the table can be
selected in User Functions: and then a value of
Units of Ω, F, C or K can be entered.

Custom tables and other RTD tables can be
confi gured by highlighting User Select RTD and
pressing ENTER.

The User Functions menu will be shown which
allows the user to add tables and specify a name
for the table. See Figure 3-7

Figure 3-7 User Functions Menu

Highlight User Functions: Default and pressing
ENTER opens the Select Name menu.
Select DEFAULT From this menu you can press
ADD or DEL to add or delete additional table

names. See Figure 3-8.

Use the

key to move UP and the to move
DOWN between User Functions:, Units: and
the Table.

The table shown in the bottom of Figure 3-7
can then be fi lled out highlighting the Table and
pressing ENTER. This will allow you to ADD
or EDIT the table.

When ADD is selected fi rst enter the Value for
the RTD, press ENTER and a prompt will be
displayed for the desired resistance in Ωs. This
can be done for as many points as required. The
procedure within the fi rmware will do linear
interpolation in between points so not all possible
values need to be entered into the table.

3.4.7 Remote Communications Settings Menu

Highlight remote settings and press ENTER key
to access remote settings. See Figure 3-8

OPERATION

19

PRS-330 Series

Figure 3-8 Remote Communications Settings

There are two selections IEEE and Ethernet.
Highlight the interface and press ENTER to see
the settings for the interface.

3.4.7.1 IEEE Interface Menu

Highlighting and pressing ENTER on IEEE will
show the menu in Figure 3-9.

Figure 3-9 IEEE Menu

Figure 3-10 Ethernet Interface Menu

There are 3 selections: IP Address:, Network
Gateway:, Network Mask:, which can be
highlighted and then press ENTER to change the
value of each. Mac Address is set at the factory
and only be changed via remote commands.

NOTE: After changing any Ethernet
confi gurations, wait 3 seconds for the settings
to save. Power-start the PRS and wait 10 seconds
for the remote control interface to load, then on
the browser attempt to load the welcome page at
the IP address.

3.4.8 About Menu

The About menu shows manufacturer, Model,
Serial number, Firmware (FW), Hardware (HW),
and Reset to Default.

There is only one selection which is IEEE
Address:. Pressing ENTER allows the IEEE
address to be set from 1 to 30.

3.4.7.2 Ethernet Interface Menu

Highlighting and pressing ENTER on Ethernet
will show the Ethernet menu in Figure 3-10.

20

Figure 3-9 About Menu

OPERATION

PRS-330 Series

The only item that can be highlighted and
changed is Reset to Defaults. Pressing ENTER
will allow the user to select YES or NO to reset
all parameters back to default. The only item this
reset does not affect is Calibration data.

3.5 Thermal emf Considerations

The PRS Series uses high-quality, low-emf
components. Thermal emf is primarily attributable
to the temperature difference between the leads
of the relay and the contacts when temperature
is applied to the coil. This emf is of the order of
5 μV per relay, but is not usually additive. The
typical worst case is <15 μV.
If the effect of tens of microvolts is signifi cant
to your application, connect to the instrument
with low-thermal-emf materials only. Copper
wire and copper alloys are recommended; brass
and steel should be avoided. Tinned copper and
solder are acceptable.

3.6 Environmental Conditions

The PRS is built, calibrated and intended for
use in a laboratory environment with a nominal

o

ambient temperature near 23

C. The accuracy
of the unit may be affected when operated in
non-laboratory environments. Always allow the
instrument to stabilize at room temperature after
unpacking or relocating the instrument. Humidity
should be maintained at laboratory conditions and
typically < 50% RH non-condensing to minimize
shifts in resistance.

3.7 Remote Operation

When the PRS is in REMOTE with front panel
locked out an REMOTE indication will be shown
in bottom half of the HOME screen. Pressing
the LOCAL key will switch the PRS-330 back
to local mode.

This emf will not be refl ected if an ac measurement

instrument is employed, and can be eliminated
by using a meter with “True Ohm” capability. In
other cases, the emf may represent a very small
component of a dc resistance measurement.

OPERATION

21

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PRS-330 Series

22

OPERATION

PRS-330 Series

Chapter 4

USB INTERFACE

4.1 Introduction

The USB connection is via a standard USB B
female connector located on the rear panel. This
can be connected to a PC via a standard USB 2.0
A Male to B Male Cable, which is included.

Figure 4-1 USB 2.0 A Male to B Male Cable

The SCPI standard provides a tree like series
of standard commands for programmable
instruments so that similar instruments by
different manufacturers can be controlled by the
same program.

4.2 Capabilities

The USB interface provides remote control over
all functions except POWER.

4.3.1 USB Interface Drivers

Normally when the PRS-330 is connected to a
computer using the USB port, Windows 7 and
higher will search for the correct driver and as
long as the computer is connected to the internet
the driver should automatically be installed.

The USB driver provides USB control through a
virtual COM Port using the Microsoft’s standard
driver for Virtual COM Ports.

Data rates and formats are below;

Baud rate: 9600 baud
Data bits: 8
Parity: none
Stop bits: 1

If the driver cannot be found the USB interface
uses a standard MCP2200 Driver. Drivers can
be found at the link below if the drivers are not
automatically installed.
http://www.ietlabs.com/Drivers/MCP2200.zip
or http://www.ietlabs.com/prs-300-ieee-ethernet.
html

4.3 USB Operation

The USB uses the command set outlined in
Appendix B. Data should be terminated with
LF line feed.

USB INTERFACE

23

Page left intensionally blank

PRS-330 Series

24

USB INTERFACE

Chapter 5

ETHERNET INTERFACE

PRS-330 Series

5.1 Ethernet Programming

The PRS-330 comes with Ethernet remote
programming capability accessed through the
RJ45 LAN connector. The connector is a RJ45
industry-standard connector found on the rear
panel. The PRS’s Ethernet connection is based
upon the ICS Ethernet/GPIB/USB to Serial
Interface Card. More information can be found
at www.icselect.com on the 9006 Ethernet/GPIB/
USB to Serial Interface Card.

Ethernet Protocols

The PRS-330 supports Raw Socket and the VXI­11 protocol which makes it easy to control from
a PC or over the company network.
Raw socket lets you telnet to it and is best
used with direct PC to instrument applications.
VXI-11 operates over Sun RPC and is a more
secure protocol that mimics GPIB control of an
instrument and provides secure communication
over a company network or over the Internet.

Raw Socket Operation

The PRS-330 is always ready for a telnet
connection. When connected, the PRS outputs
its IDN message to confi rm the connection.
All raw socket messages are terminated with
a linefeed. Carriage returns and ignored. A
backspace character causes the prior character
to be deleted. Communication timeout is two
minutes and it is recommended that the client
issue a Space-BS sequence on an occasional
basis, less than the timeout, to reset the timeout

counter.

VXI-11 Background

VXI-11 is a communication standard developed
in conjunction with the VISA Specifi cation. The
specifi cation defi nes a VXI-11.3 interface like the
PRS as an instrument which can be controlled in
Windows systems by programs that make VISA
or SICL library calls and in UNIX/LINUX or
similar operating system with RPC calls. The
VXI-11 specifi cation provides an RPCL (Remote
Procedure Call Library) that can be used by
virtually any operating system to control the
PRS. Microsoft’s RPC is not ONC compliant
and cannot be used with a VXI-11.3 device like
the PRS. An VXI-11.3 interface like the PRS will
operate in an LXl system and it supports LXI’s
‘VXI Discovery Method’.

5.2 Network Setup

The PRS-330 includes an internal WebServer
with HTML web pages that can be accessed by a
web browser from any computer. The web pages
let the user quickly change the PRS network
settings. The default IP address is 192.168.1.253
static.

5.3 Ethernet Test Keyboard

To assist the user in setup and communication
the VXI-11kybd program can be used which
includes defi ned RPC calls to change the PRS

ETHERNET INTERFACE OPTION

25

PRS-330 Series

network settings.

VXI-11 Keyboard Control Program provides
interactive control of VXI-11 instruments from
the computer keyboard without having to write a
program. The VXI-11 Keyboard program is the
ideal utility program for confi guring and testing
the PRS or any VXI-11 compatible instrument.
Use the VXI-11kybd program to exercise the
interface or to try out commands before using
them in a program. The VXI-11kybd program
can be found on the PRS product page at www.
ietlabs.com

Versatile Programming

The PRS-330 can be easily controlled by several
programming techniques and languages because
it is a VXI-11.3 instrument. If you program
with LabVIEW, National Instruments’ VISA
supports VXI-11.3 instruments like the PRS. NI’s
Measurement and Automation Explorer treats
the PRS as a TCP/IP compliant device. Agilent’s
VISA library supports VXI-11.3 instruments and
the Agilent Connection Manager sees the PRS as
a TCP/IP instrument.

If you are a Visual Basic, VB.Net or C/C++
programmer, you can write your program to
call Agilent’s or National Instruments’ VISA
or Agilent’s SICL library in the Windows
environment.

If you program with Java then you can write a
PRS control program that can be easily moved
to many different operating systems.

The Java jGpibEnet project on SourceForge was
developed using an ICS 8065 Controller similar
to the PRS Controller.

5.4 Network Confi guration

This paragraph confi gures the 9006 card in the
PRS for operation on your network. The board’s
digital interface is confi gured later by sending
commands as outlined in Appendix A.

When shipped, the boards are confi gured with
default settings outlined in Table 4-1 Default
Settings.

Command Function Factory Setting

IP Mode Static or DHCP

Mode

IP Address 0.0.0.0 to

255.255.255.255.0

Net Mask 0.0.0.0 to

255.255.255.255.0

COMM Timeout Sets socket timeout 120 sec.

Auto Disconnect Aborts socket if link

count goes to 0

Static

192.168.1.254

255.255.255.0

Off

If you use LINUX or any other fl avor of UNIX
like SunOS, IBM-AIX, HP-UX, or Apple’s OS X,
you can communicate with the PRS through RPC
over TCP/IP. RPC (or Remote Procedure Calls)

provides an invisible communication medium for
the developer. The VXI-11 specifi cation provides
an RPCL (Remote Procedure Call Library) that
can be used by virtually any operating system to
control the PRS.

26

Table 4-1 Default Settings

Review the Table with your network administrator
and decide on which settings, if any, that need
to be changed. Table 4-1 provides detailed
information about each network setting to help
you with your decisions. The minimum change
is to set a static IP address so your PC can
communicate with the board.

NOTE: After changing any Ethernet

ETHERNET INTERFACE OPTION

confi gurations, wait 3 seconds for the settings
to save. Power-start the PRS and wait 10 seconds
for the remote control interface to load, then on
the browser attempt to load the welcome page at
the IP address.

The network confi guration can be changed and
the board’s MAC Address can be read with a web
browser, by running ICS’s VXI-11 Confi guration
Utility on a WIN32 or WIN98 PC. ,

5.5 Web Browser Confi guration Method

This method uses a standard browser such as
Firefox, Internet Explorer or Safari to view and
change the current network settings.

1. Temporarily disconnect the computer from
the company network. Connect the PRS and
computer running the browser using a standard
Ethernet Cables to a hub or switch. Temporarily
disconnect the local network connection to avoid
network confl icts until the board is confi gured.

PRS-330 Series

Figure 4-2 9006 Connected to the local hub

2. Apply power to the PRS. Set the Remote local
switch to Remote.

3. Check your computer’s network settings to
be sure its IP address is in the 192.168.1.xxx
range so it can communicate with the PRS
Ethernet board’s default IP address. If it is not,
it must be set before proceeding. Use the values
shown below. For Windows PCs, right-click on
My Network Places and click on Properties.
Right-click on Local Area Connection and click
Properties. Highlight Internet Protocol (TCP/IP)
and click Properties. If your PC’s IP address is in
a different range, record the current settings and
temporarily set the following network values:

Figure 4-1 9006 Connected to the local hub

An alternate connection is to use an Ethernet
Crossover Cable to connect the computer directly
to the PRS for initial confi guration. This will
eliminate any potential network confl icts while
confi guring the PRS.

ETHERNET INTERFACE OPTION

Check ‘Use the following IP Address’
IP Address 192.168.1.254
Subnet mask 255.255.255.0

4. Open the browser and enter the default IP
address of 192.168.1.254 for new units (or your
last set address for older units) in the browser
address window.

5. A Welcome Page similar to the one shown
Figure 4-3 should appear in your browser.

6. If you want to change any of the settings, press
the ‘Update Confi guration’ key. A Confi guration
Page similar to the one shown in Figure 4-4

27

PRS-330 Series

should appear in your browser.

Figure 4-3 9006 Welcome Page

Flash’ key when done. A Confi rmation Page
similar to the one shown in Figure 4-5 will appear
in your browser.

Figure 4-5 9006 Confi rmation Page

Figure 4-4 9006 Confi guration Page

7. Enter the new settings as desired. If you select
DHCP for the TCP/IP Mode, the page blanks out
the IP, Net and Gateway addresses as they will
be supplied by your DHCP server. Check the
entered values carefully as the unit’s webserver
does minimal error checking. Press the ‘Update

8. Your new settings have been saved in the
board’s fl ash memory. You have to reboot the unit
or power cycle it for the changes to take affect.
Press the ‘Reboot’ key to reboot the unit now
or the ‘Return to the Confi guration Page’ key to
revisit the new settings.

5.6 VXI-11 Confi guration Utility Method

The VXI-11 Configuration Utility program
is called ‘VXI11_confi g.exe’ and runs in any
WIN32 PC with Windows 98, Me, 2K, XP,
Vista, 7 and Server 2003 operating systems. The
VXI11_confi g.exe program can be found on the
PRS product page at www.ietlabs.com.

The VXI11_confi g program can be run from the
CD or can be installed onto your hard disk and
run from the installation directory.

VXI11_confi g.exe is a Visual Basic program and
requires that either Microsoft’s Visual Studio 6
or VBruntime6 be installed on your PC to run.

28

ETHERNET INTERFACE OPTION

PRS-330 Series

gg

1. Connect the board directly to the WIN32 PC
that will be running the Confi guration Utility.
Disconnect the PC from the company network
and use the supplied Ethernet Crossover Cable to
connect the PC to the board as shown in Figure
4-6. This will eliminate any potential network
confl icts while confi guring the board.

Figure 4-6 9006 Connected to PC with a
Crossover Cable

Alternately, use a standard Ethernet patch cable
to connect the 9006 to the same hub or switch
that the PC running the Confi guration Utility is
connected to as shown in Figure 4-7. Temporarily
disconnect the local network connection to avoid
network confl icts until the board is confi gured.

Places and click on Properties. Right-click on
Local Area Connection and click Properties.
Highlight Internet Protocol (TCP/IP) and click
Properties. If your PC’s IP address is in a different
range, record the current settings and temporarily
set the following network values:

Check ‘Use the following IP Address’
IP Address 192.168.1.254
Subnet mask 255.255.255.0

4. Run the VXI11_config program. The
Confi guration Utility opens a window as shown
in Figure 4-8. Initially only the Find Server, Help
and Exit keys are enabled on the program
window. The other keys will be enabled as you
advance through the program.

5. Click on the Find Server key. The program
scans for all VXI-11 Services connected to the
local LAN or to your PC. (The 9006 is an RPC
server which provide a VXI-11 Service) The
results are displayed in the Results box.

6. When the servers(s) have been found, use the
pulldown arrow in the Found Servers box to view
the Found Server addresses. The board’s
default address is 192.168.1.254. Highlight the
board’s IP address and click the Create Link key.
If the server is not found, you can enter the default
IP address (192.168.1.254) in the Found Servers
box. Click the Create Link key.

Figure 4-7 9006 Connected to the local hub

2. Apply power to the board

3. Check your PC’s network settings to be sure
its IP address is in the 192.168.1.xxx range so
it can communicate with the board’s default IP
address. To check, right-click on My Network

ETHERNET INTERFACE OPTION

29

Figure 4-8 VXI-11 Confi guration Utility

(Showing all configuration choices with no
changes)

7. When the link has been created, device model
number(s) will appear in the ‘Select Device to
be Confi gured’ box. Highlight the desired model
number and click the Confi gure key to start the
confi guration process.

8. The Confi guration Choices box displays only
one line with the fi rst parameter to be changed
and its current setting. If you like the current
setting, click Enter to advance to the next
parameter. If you want to change the setting, type
a new value in the New Value box and click Enter.
The program will send your setting to the board
and read back the new setting. Repeat as needed
to make another change or click Enter again to
advance to the next parameter.

PRS-330 Series

10. When done, the Save Confi guration key is
enabled if you changed any settings. Click the
Save Confi guration key to save the values in the
board’s fl ash memory. If you did not make any
changes you can just exit the program.

11. The board has to be power cycled or rebooted
before the confi guration changes take affect.
Click the Reboot key to reboot the board and use
the new settings.

12. Press the Exit key to quit the VXI11_confi
g program.

13. If the IP address was changed to an address
outside the 192.168.1.xxx range in step 3, your
PC’s network settings will have to be changed to
communicate with the board. Exit the VXI11_
confi g program and restore the PC’s network
settings.

5.7 Resetting Default Network

Settings

The board can be reset to the default network
settings listed in Table 4-2 at any time by holding
the LAN Reset Key in for 5 seconds while
applying power to the board. Access to this key
is on the rear panel of the PRS-330.

9. Repeat step 8 for each confi guration parameter.
Figure 4-8 shows the VXI-11 Configuration
Utility after all parameters have been entered for
a Model 9006. Click the Redo From Start key if
you need to start over or if you want to change
any of the prior settings

30

ETHERNET INTERFACE OPTION

The Digital I/O confi guration values are not
affected by the LAN Reset operation.

Command Function Factory Setting

IP Mode Static or DHCP

Mode

IP Address 0.0.0.0 to

255.255.255.255.0

Net Mask 0.0.0.0 to

255.255.255.255.0

COMM Timeout Sets socket timeout 120 sec.

Auto Disconnect Aborts socket if link

count goes to 0

Static

192.168.0.2

255.255.255.0

Off

Table 4-2 Default Settings

5.8 PRS Programming

A PRS SCPI command reference is in­cluded in Appendix A. This gives a complete
set of commands.

PRS-330 Series

An example of commands to be sent to
place the PRS in remote, this must be done
fi rst otherwise the will be no remote control of
output impedance, and then confi gure the unit
for a specifi c impedance value.

Where the command string is constructed
as described in Appendix A and Appendix B.

A command string might be, for example:

SOURce:DATA 1000000.1

ETHERNET INTERFACE OPTION

31

PRS-330 Series

32

ETHERNET INTERFACE OPTION

PRS-330 Series

Chapter 6

IEEE INTERFACE

6.1 Introduction

The PRS-330 is a IEEE-488.2-1987 and SCPI

1994.0 compatible instrument. The PRS-330
IEEE-488 interface is based upon the ICS
Ethernet/GPIB/USB to Serial Interface Card.
More information can be found at www.icselect.
com on the 9006 Ethernet/GPIB/USB to Serial
Interface Card.

The IEEE STD 488.2 covers the electrical and
mechanical bus specifi cations, and state diagrams
for each GPIB bus function. It also establishes
data formats, common commands for each 488.2
device and controller protocols. The standard is
available on-line at http://www.ieee.org.

The SCPI standard provides a tree like series
of standard commands for programmable
instruments so that similar instruments by
different manufacturers can be controlled by the
same program. SCPI information and a command
reference are located in Appendix A.

Other tutorials are available on-line; consult IET
for additional information. A software GPIB
“keyboard” can be found at www.ietlabs.com

6.2 Capabilities

The IEEE option provides remote control over
all functions except POWER. The IEEE option
responds to all Basic Commands in Appendix
B and all IEEE.2 Mandated common commands
in Appendix A.

6.3 Address Switch and Communications
Settings

The default GPIB address is 4. This address can
be changed remotely by sending the command
SYSTem:ADDR <n> where n is 0 - 30.

6.4 GPIB Test Keyboard

To aid the user in operating the PRS, a GPIB
“Keyboard” Controller program - the easiest
way to control GPIB devices without writing
a program - is available from IET. This GPIB
Keyboard program automatically finds your
device at start-up and it lets you enter just the data
that you want to send to the device. This program
works with ICS, Measurement Computing and
National Instruments controllers.

IEEE INTERFACE OPTION

To implement, request a download of ICS_
GPIBkybd_Install.zip from IET Labs Tech

Support.

33

Unzip the fi le and follow instructions to install.

Open the application. You may use the Find
Listeners key to confi rm that the PRS unit is
recognized. Other instruments may also be
recognized at this time.

PRS-330 Series

IEEE INTERFACE OPTION34

PRS-330 Series

Chapter 7

PROGRAMMING

7.1 Program Commands

The USB, Ethernet and IEEE interface can be
programmed via any of the commands listed in
Appendix A and B.

For USB <lf>, <cr> or <crlf>, can be used as
terminator. The device returns in this case <crlf>.

The device performs all commands previously
sent after it receives a terminator.

PROGRAMMING

35

Page left intensionally blank

PRS-330 Series

36

PROGRAMMING

Chapter 8

MAINTENANCE

PRS-330 Series

8.1 Verifi cation of Performance

8.1.1 Calibration Interval

The PRS Series instruments should be verifi ed
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.

8.1.2 General Considerations

It is important, whenever testing the PRS Series
Decade units, to be very aware of the capabilities
and limitations of the test instruments used. Such
instruments have to be signifi cantly more accurate
than the specifi ed accuracy for all applicable
ranges in order to perform this task, allowing for
a band of uncertainty of the instrument itself, the
test setup and the environment; consult IET Labs
for information.

It is important to allow both the testing instrument
and the PRS-330 to stabilize for a number of
hours at the nominal operating temperature
of 23oC, and at nominal laboratory conditions
of humidity. There should be no temperature
gradients across the unit under test.

In the case of the PRS-330 a Kelvin type 4-wire
test terminals should be used to obtain accurate

low-resistance readings.

Steps should be taken to minimize thermal-emf
effects, by maintaining an even temperature and
by using only low-emf connectors. Use of meters
with a “True Ohm” function is recommended.

Proper metrology practices should be followed
in performing this verifi cation.

8.1.3 Calibration Procedure

Equipment Required:

Keysight 3458A, Fluke 8508A or equivalent
KK-100, TL-600 Kelvin Cable or equvalent.

Procedure:

Fluke 8508A or Keysight 3458A using 7 ½ digits
of resolution or better is connected to the binding
posts of the PRS-330 using a 4 terminal Kelvin
connection.
The gold shorting links must be removed on the
binding posts of the PRS-330.

The PRS-330 consists 43 internal resistors
which are combined in either series or parallel
to achieve the programmed resistance. The gold
shorting links must be removed on the binding
posts of the PRS-330.

These resistors require periodic measurement to
keep the PRS-330 within published specifi cations.
The resistors are measured using a DMM. The
measured value is then stored in a table within

MAINTENANCE

37

the memory of the PRS-330. The measured
values of the resistors are used in an algorithm
to determine which resistors are used to create
the programmed resistance value.

In addition to the 43 resistors the residual
internal lead resistance is also measured at time
of manufacture and entered into memory. The
internal lead resistance does not need to be
measured again unless repair has been performed
to the PRS-330.

Below is a list of the 43 resistors and their
nominal resistance value. These resistors should
be within ±1% of the nominal value for R1 to R5
and ±0.1% of the nominal value for R6 and higher
to ensure proper operation of the PRS-330. If the
measured value of the resistor is outside of these
specifi cations service is required.

Resistance

Number

Nominal Resistance

Value

R1 0.17 Ω
R2 0.35 Ω
R3 0.7 Ω
R4 1.37 Ω
R5 2.66 Ω
R6 5.15 Ω
R7 10.2 Ω
R8 20.0 Ω
R9 38.8 Ω
R10 75.6 Ω
R11 148.0 Ω
R12 287.0 Ω
R13 570.0 Ω
R14 1.13 kΩ
R15 2.23 kΩ
R16 4.4 kΩ
R17 8.7 kΩ
R18 17.0 kΩ
R19 33.3 kΩ
R20 66.0 kΩ
R21 130.0 kΩ
R22 258.0 kΩ
R23 506.0 kΩ
R24 1.0 MΩ
R25 2.0 MΩ
R26 3.99 MΩ
R27 7.8 MΩ
R28 15.0 MΩ
R29 30.0 MΩ
R30 60.0 MΩ
R31 120.0 MΩ
R32 3.55 kΩ
R33 7.39 kΩ
R34 16.4 kΩ
R35 33.8 kΩ

PRS-330 Series

38

MAINTENANCE

PRS-330 Series

R36 72.2 kΩ
R37 147.0 kΩ
R38 300.0 kΩ
R39 600.0 kΩ
R40 1.23 MΩ
R41 2.48 MΩ
R42 5.0 MΩ
R43 10.0 MΩ

During the adjustment process the fi rmware
cycles through each resistor and the technician
can enter the measured resistance value in
ohms. This should be done with a minimum
of 7 ½ digits of resolution. The accuracy of
measurement should be significantly more
accurate than the ±(70 ppm + 1 mΩ) for all
resistance values.

8.1.5 Calibration Menu and Process

To enter into the calibration process, press the
MENU key, push in the CAL ENABLE key
and keep pressed, and then select Instrument

Calibrate.

ENTER. The menu in Figure 8-2 will be shown.

Once this menu is displayed the CAL. ENABLE
key can be released.

Figure 8-2 Instrument Calibration Menu

Full Calibration allows calibration of 1 or all 43
resistors.

Trace Calibration is only required if the PRS-330
requires service which involves changing of the
relay board, or internal wiring between binding
post and the relay board. This compensates for
the buss wire resistance between the main board
and binding posts.

Calibration History allows the history of each
resistor to be reviewed showing resistance at
each calibration date.

Figure 8-1 Main Menu with CAL ENABLE
pressed

Only when the CAL. ENABLE key is pressed
does the Instrument Calibration selection
become available.

Select Instrument Calibration and press

MAINTENANCE

8.1.6 Full Calibration (adjustment)

Full Calibration can be performed by selecting
Full Calibration and pressing the ENTER key.
A password is required as shown in Figure 8-3.

Figure 8-4 shows entry of the password which is
IET. note tapping twice on the alpha keys will
select the second letter.

At the end of the process select all calibration
values will be saved into memory.
At anytime pressing the MENU key will exit
calibration without making any changes.

39

Figure 8-3 Password entry screen

PRS-330 Series

a DMM using a 4 terminal Kelvin connection,
making sure the shorting links are not on the
binding post.

IET Labs uses the Fluke 8508A, set to 7 ½ digits
of resolution, during the adjustment process to
ensure the PRS-330 meets specifi cations.

IET Labs offers the PRS-DMM software which
works with the PRS-330 and Fluke 8508A or
Keysight 3458A to automate this adjustment
process. See Chapter 9.

Once the resistance is measured the resistance
value can be manually entered in ohms using
the keypad.

Figure 8-4 Entry of IET as password

Once the password IET has been input via touch
screen press the ENTER key. This will open the
Calibration screen as shown in Figure 8-5.

Figure 8-5 Resistor 1 Calibration Screen

The process is to measure the resistance with

Once the resistance has been entered the NEXT
key can be pressed to move to the next resistor
value R2. The PREV key can be used to go back
to the previous resistance value if required. There
are 43 resistors which require calibration.

At anytime during the process the CNCL key
can be pressed to cancel the calibration process.
Cancelling the calibration process will not save
any calibration data taken and the previous
calibration data is used.

Pressing the EXIT key will save the current
calibration data into memory. You will be
prompted to enter the calibration date. and then
the data is saved into memory. This data can be
reviewed in the Calibration History menu.

8.1.7 Calibration History

The Calibration History menu is in the Calibration
menu. This allows the use to view the resistance
and date the adjustment procedure as perform in
Section 8.1.4.

This information can be used to look at the drift
of each of the 43 internal resistors. This data can

40

MAINTENANCE

be viewed in this menu. If exporting this data
is required see Appendix B remote commands
which allow this data to be transferred to a PC.

Figure 8-6 Calibration History Menu

PRS-330 Series

From the Instrument Calibration menu select
Calibration History and press ENTER.The menu
in Figure 8-6 will be shown.

Each time an internal adjustment of the resistors
is performed and saved per Section 8.1.4, a new
line is added in the table.

Use the

key to move UP and the to move
DOWN which will show the resistors R1 to R43
and the calibration history of each resistor.

Press CNCL to return to the previous Instrument
Calibration menu.

MAINTENANCE

41

8.2 Replaceable Parts List

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

Not Shown PRS-330-Bail-Feet kit 4 x feet and bale kit

Not Shown PRS-330 Relay Board Relay Board Complete

Not Shown PRS-330 CPU Board CPU Board Complete

Not Shown PRS-330 Remote Interface USB,IEEE,Ethernet Interface Card

4 PRS-330 Touch Screen Touch Screen

Not Shown PRS-330 BP Board Front Binding Post Board Front

Not Shown PRS-330 BP Board Rear Binding Post Board Rear

5 PRS-330 FP Front Panel with Overlay and Bezel

6 PRS-330 Keypad Keypad and Keypad board

7 PRS-330 Power Switch Power Switch Illuminated

PRS-330 Series

5

4

6

7

2

3

1

42

MAINTENANCE

Chapter 9

PRS-DMM Self Adjusting Software

PRS-330 Series

9.1 PRS-DMM Self Adjusting Software

9.1.1 Overview

The PRS-DMM Self Adjusting Software is a
Windows based software package using LabVIEW
2013 RTE.

The software is designed to be used with the PRS­330 Programmable Resistance Substituter and the
Keysight 3458A or Fluke 8508A DMMs.

The DMM is used to measure the resistance of the
PRS-330, and then the software adjusts the output
resistance of the PRS-330 to achieve the closest
possible resistance value to the target resistance
value.

This can improve the accuracy of the PRS-330
from ±(70 ppm + 1 mΩ) to better than ±10 ppm
short-term without switching.

9.1.2 General Requirements

• Kelvin cables between PRS-330 and
Fluke 8508A

• GPIB cables as necessary

9.1.3 Software Installation

Install the PRS-DMM Self Adjusting Software
using the supplied USB stick. This will install
the PRS-DMM software as well as the LabVIEW
2013 RTE. This software is also available at
http://www.ietlabs.com/prs-dmm.html

If using the PRS-330 with standard USB
interface, MCP2200 driver should be installed.

9.1.4 Connection between DMM and PRS­330

Connect the PRS-330 to the DMM using good
quality low thermal EMF cables using a 4
terminal kelvin connection.

If the end use of the PRS-330 will be 2 Wire then
keep shorting links installed. In the menu of the
PRS-330 it should be confi gured for “2W” Mode.

The PRS-DMM Self Adjusting Software does
require:

• Windows 8 or Windows 10 PC

• National Instruments GPIB-USB-HS or
equivalent GPIB interface

• Fluke 8508A DMM or Keysight 3458A
DMM

• PRS-330 Programmable Resistance
Substituter

PRS-DMM SOFTWARE

If the end use of the PRS-330 will be 4 wire then
remove shorting links. In the menu of the PRS­330 it should be confi gured for “4W” mode.

See section 3.4.10 for more information on
2-wire and 4-wire connections.

43

PRS-330 Series

9.1.5 Connections of PRS and .DMM

Connect the 3458A or 8508A DMM to the PC via
GPIB. Connect the PRS-330 to the PC via GPIB
or USB. Make sure the addresses are different
on DMM and PRS-330.

9.2 PRS-DMM Main Screen

The main screen of the PRS-DMM software is
shown below.

Clicking on the Calibrate key starts the process
of of adjusting. The DMM Measures and adjusts
the PRS-330 to achieve the closest value possible
to the entered target value. The accuracy depends
upon the MEASUREMENT SPEED . See
section 9.3.5.

9.3 PRS-DMM Settings

9.3.1 PRS-DMM Settings Screen

The Settings screen is shown in Figure 9.2. This
menu should be confi gured fi rst to set address of
the PRS-330 and DMM.

This menu also allows for adjustment of the PRS­330 which automates the adjustment process of
the PRS-330 as described in section 8.4.1.

Figure 9.1 PRS-DMM Main Screen

There are 4 keys; Main, Settings, About Us and
Exit.

9.2.1 PRS-DMM Main Screen Operation

The main screen of the PRS-DMM allows the
user to select Resistance or RTD tables, and it
also allows to be entered the target resistance
value or temperature.

Assuming that the PRS-330 is connected to the
PC and turned on, any value entered as a target
value will automatically switch the PRS-330 to
that resistance or resistance equivalent to the
entered temperature value.

Figure 9.2 PRS-DMM Settings Screen

9.3.2 PRS Settings

PRS Setting screen allows the operator to select
the COM port or GPIB address of the PRS-330.
Make sure the PRS-330 and DMM are turned on
and connected to the PC.

If the address or COM port of the PRS-330 or
DMM is not shown in the I/O box then click on
refresh. Select the GPIB address or COM port
and then click the Initialize key. The IDN string

44

PRS-DMM SOFTWARE

will be shown in the white box along with a
Success indication.

Click Exit key to return to Setting Screen once
PRS has been detected.

PRS-330 Series

Select the GPIB address and then click the
Initialize key. The IDN string will be shown in
the white box along with a Success indication.
The PRS-DMM software will configure the
DMM for resistance measurements, appropriate
resolution 7 ½ digits for slow, 6 ½ digits for
medium and fast, 4 wire measurements and
autorange ON.

The 8508A will also be configured for Low
Current, Fast AD Integration OFF, and Analog
Filter OFF.

If additional commands need to be sent to the
DMM, click on the Confi gure Key and enter the
commands in the text box.

Figure 9.3 PRS Settings Screen

9.3.3 Meter Settings

Meter Setting screen allows the operator to select
which DMM will be used either the Fluke 8508A
or the Keysight 3458A. The GPIB address of the
DMM can also be set in this menu. Make sure
the DMM is turned on and connected to the PC.

Once the commands have been entered press the
Confi gure key. Any commands will be send to
the DMM during initialization of the DMM.

Figure 9.5 Meter Confi gure Screen

Click Exit key to return to Setting Screen once
DMM has been detected.

Figure 9.4 Meter Screen

PRS-DMM SOFTWARE

45

PRS-330 Series

9.3.4 Adjust PRS

Clicking on the Adjust PRS key will step the
operator through the PRS-330 adjustment
procedure. The procedure consists of measuring
all 43 internal resistors using the DMM and
storing the actual resistance values into a table.
These resistance values are used in the algorithm
to create the programmed resistance value. See
section 8.1.4 for more information.

9.3.5 PRS-DMM Speed

There are three selections for PRS-DMM Speed.
These selection affect the accuracy from the
target value and time to make the measurements.
Slow measurements are made with 7 ½ digits of
resolution, and measurements and adjustments
are made until the accuracy is better than ±20
ppm.

Medium measurements are made with 6 ½ digits
of resolution and measurements and adjustments
are made until the accuracy is better than 40 ppm.

Fast measurements are made with 6 ½ digits
of resolution. There are no adjustments made
in fast mode. The value from the DMM is just
displayed.

The uncertainty of the measurement is also
displayed. The uncertainty is based upon the
specifi cations given in the manual for the Fluke
8508A or Agilent 3458A. The uncertainty is
based upon either 6 ½ or 7 ½ digits of resolution,
absolute uncertainty for 365 days and a 95%
confi dence level.

46

PRS-DMM SOFTWARE

Appendix A

SCPI COMMAND REFERENCE

PRS-330 Series

SCPI is an acronym for “Standard Commands for
Programmable Instruments”. For additional in­formation or an on-line copy of this standard, see:

http://www.scpiconsortium.org.

The IEEE 488.2 Standard was established in
1987 to standardize message protocols and
status reporting and to defi ne a set of common
commands for use on the IEEE 488 bus. IEEE

488.2 devices are supposed to receive messages
in a more fl exible manner than they send. A
message sent from GPIB controller to GPIB
device is called: PROGRAM MESSAGE.
A message sent from device to controller is
called: RESPONSE MESSAGE. As part of the
protocol standardization the following rules were
generated:

(;) Semicolons separate messages.
(:) Colons separate command words.
(,) Commas separate data fi elds.
<nl> Line feed and/or EOI as last character
terminates a ‘program message’.
Line feed (ASCII 10) and EOI
terminates a RESPONSE MESSAGE.
(*) Asterisk defi nes a IEEE 488.2 common
command.
(?) Ends a query where a reply is expected.

SCPI builds on the programming syntax of IEEE-

488.2 to give the programmer the capability of
handling a wide variety of instrument functions

in a common manner. This gives all instruments
a common “look and feel”. SCPI commands are
not case-sensitive.

The portion of commands shown in capitals
denotes the abbreviated form of the keyword.
Either the abbreviated or whole keyword may
be used when entering a complete command.
There must be a space between the command
and a parameter or channel list. Multiple SCPI
commands may be concatenated together as a
compound command by using semicolons as
command separators.

Keywords shown inside braces [ ] are
defaults, and are optional when constructing a
PROGRAM MESSAGE.

Commands not recognized have no effect
on the unit’s operation and will set the
corresponding bits in the Standard Event
Status Register. SCPI commands that end with
a question mark ‘?’ are queries. All queries
should be followed by reading their response to
avoid data loss.

Semicolon ‘;’ is used to separate more
commands written on one line.

Terminators: For GPIB interface each
command line must end with line feed <lf>.
Response from the device also returns line feed
<lf>.

APPENDIX A 47

PRS-330 Series

IEEE-488.2 Common Commands

*IDN?
Returns instrument identifi cation “IET
Labs,PRS-330,<Serial Number>,<software
version>”
*ESR?
Returns the read of the event status register.
*STB?
Returns the read of the status byte register.
*ESE?
Returns the read of the event status enable
register.
*SRE?
Returns the read of the service request enable
register.
*ESE
Set the event status enable register value

*SRE
Set the service request enable register value
*RST
Reset the buffer
*TST?
Self test query
*CLS
Clear standard event status register
*OPC
Operation complete
*OPC?
Operation complete query
*WAIT
Wait until operation is complete before execut­ing next command(No Function in PRS)

*PCS
Power-on Status Clear

Note: Remote command can start with or without
* symbol for compatibility.

APPENDIX A48

PRS-330 Series

Appendix B

PRS-330 COMMON COMMANDS

COMMON Commands:

*IDN? Returns instrument identifi cation “IET Labs Inc.,PRS-330,<Serial

number>,<software version>”

Serial number in the form “Ax-xxxxxxxx” x = 0 to 9. A = Alpha can be A to Z.

*TST? Self-Test Returns ASCII 0 or 1, 0 = bad or 1 = good

*RST Returns PRS-330 to default “power on” condition

*SAV <number> Saves current resistance value into memory location 0 to 9
Number is 0 to 9

*RCL< number> Recalls resistance value from memory location 0 to 9
Number is 0 to 9

SYSTEM Commands

SYSTem:SERIal <Ax-xxxxxxxx> Sets the serial number in non-volatile memory < serial num-

ber>

Serial number in the form “Ax-xxxxxxxx” x = 0 to 9. A = Alpha can be A to Z.

SYSTem:SERIal? Returns Serial number

SYSTem:CONTrast <number> Sets system contrast specifi c number from 0 to 15

SYSTem:KEY <number> Same as pressing key on front panel of PRS-330
<Number> is 0 to 24
keys 0-9 0 – 9
OPEN 14
MENU 15
TABLE 16
Decimal Point 21
BACK 23
ENTER 24
Short 17
Open 18

SYSTem:LOCal: This command places device in the LOCAL mode and unlocks all keys

APPENDIX B

49

PRS-330 Series

on front panel of the device. The Command is valid only for RS232, and USB interfaces.

SYSTem:REMote This command places device in the REMOTE mode and locks all

keys. The Command is valid only for RS232, and USB interfaces.

SYSTem:MODEl? Returns model number PRS-330 or PRS-370

SYSTem:SVERsion? Reads system version as a string <n.nn> where n = 1 to 9

SYSTem:HVERsion? Reads hardware version as a string <n.nn> where n = 1 to 9

CALIBRATION Commands

CALIbrate:RESistance Goes into calibration mode starting at resistor 1 and then progressing
to resistor 43. Each time the command CALI:RES:SET is used the resistor number is automatically
incremented by 1.

CALIbrate:RESistance? Returns resistance number to be calibrated.

Numbers 1 to 43

CALIbrate:RESistance:SET <number> Sets calibrated value of resistance in ohms into mem­ory. <number> is a fl oating point number representing the resistance value in ohms for the internal
resistor being measured. Each time the command CALI:RES:SET is used the resistor number is
automatically increments by 1.

CALIbrate:RESistance:SET? Returns the calibrated value of resistance in ohms

CALIbrate:DATE <mmddyyyy> Sets calibration date into memory

CALIbrate:DATE? Returns calibration date in format mmddyyyy

CALIBrate:HISTory:DATe <MMDDYYYY> Selects calibration date to retrieve data from

CALIBrate:HISTory:RES<number> ? Returns the resistance value based history date and
resistance <number> 1 to 43

APPENDIX B50

PRS-330 Series

SOURCE Commands

SOURce:DATA <display value> Sets output resistance of the PRS-330 if table is set to

None or the resistance value corresponding to the display value for the table selected.

Display value in form of number and decimal point representing desired display value.

example SOURce:DATA 1.000002 would set resistance value to 1.000002 Ω if Table is set to

None.

SOURce:DATA? Returns display value currently shown in the PRS display

SOURce:RESistance <display value> Sets output resistance of the PRS-330 if table is set to

None or the resistance value corresponding to the display value for the table selected.

Display value is in the form of number and decimal point representing desired display value.

This is the same as SOURce:DATA command.

example SOURce:RES 0 would set display value to 0 and if Table is set to PT-100 or PT-1000 this
would represent the resistance value depending upon how the table is confi gured. If in Celsius and PT-
100 then resistance of 100 Ω would be set at output of PRS-330.

APPENDIX B

51

PRS-330 Series

CONFIGURE Commands General

CONFigure:SELect <2 or 4> Sets PRS-330 for 2 wire or 4 wire mode.

CONFigure:SELect ? Returns number corresponding to 2 wire or 4 wire mode.
2 = 2 wire and 4 = 4 wire

CONFigure:TERMinal <FRONT, REAR> Selects front or rear binding posts

CONFigure:TERMinal? Returns FRONT or REAR

CONFigure:SWITching <FAST, OPEN,SHORT>

CONFigure:SWITching? Returns FAST, OPEN, SHORT

CONFIGURE DMM Mode (PRS-370 Only)

CONFigure:PRSDMM:ACCUracy <SLOW, FAST> Sets resolution of DMM 7 ½ or 6 ½

respectively

CONFigure:PRSDMM:ACCUracy? Returns <SLOW, FAST>

CONFigure:PRSDMM:METEr <8508A, 3458A> Sets which DMM is used

CONFigure:PRSDMM:METEr? Returns string corresponding to selected DMM 8508A, 3458A

CONFigure:PRSDMM:ADDRess <1 - 30> corresponding to IEEE address 1 to 30 of DMM

CONFigure:PRSDMM:ADDRess? Returns IEEE address of for DMM <1 - 30>

APPENDIX B52

PRS-330 Series

CONFIGURE IEEE/Ethernet

CONFigure:IEEEAddress <number> Range 1 to 30

CONFigure:IEEEAddress? Returns <number> corresponding to IEEE address 1 to 30

CONFigure:ETHErnet:IP <string> with format of ###.###.###.### where # is 0 to 9

CONFigure:ETHErnet:IP? Returns IP address as a string ###.###.###.###

CONFigure:ETHErnet:GATE <string> with format of ###.###.###.### where # is 0 to 9

CONFigure:ETHErnet:GATE? Returns network gateway address as a string ###.###.###.###

CONFigure:ETHErnet:MASK <string> with format of ###.###.###.### where # is 0 to 9

CONFigure:ETHErnet:MASK? Returns network mask address as a string ###.###.###.###

CONFigure:ETHErnet:MAC? Returns MAC address as a string

CONFIGURE Standard Values

CONFigure:STDValue <SET, STANard, DECade, RADiometric>

CONFigure:STDValue? Returns SET, STANard, DECade, RADiometric

CONFigure:STDValue:SET <number> 0.1 - 10M

CONFigure:STDValue:SET? Returns <number> 0.1 - 10M

CONFigure:STDValue:STD <1, 5, 10> EIA resistor %

CONFigure:STDValue:STD? Returns 1, 5, or 10 corresponding to EIA Resistor %

CONFigure:STDValue:DECade <number> 0.1 - 10M

CONFigure:STDValue:DECade? Returns <number> 0.1 - 10M

CONFigure:STDValue:RADiometric <number> 0.001 - 10 where number is in %

CONFigure:STDValue:RADiometric? Returns <number> 0.001% - 10%

APPENDIX B

53

PRS-330 Series

CONFIGURE Tables

CONFigure:RTD <P100C, P100F, P1000C,P1000F>

CONFigure:RTD? Returns which RTD table is selected P100C, P100F, P1000C, or P1000F

CONFigure:TABLe:SELect <number> Selects Table to be used, <number> is 0 to 9. 0 is no

table with display shown in ohms and 1 , 2, 3 and 4 are predefi ned and 5 to 9 are user defi ned tables

CONFigure:TABLe:SELect? Returns table number that is selected

CONFigure:TABLe:NAME <name> Sets Table name, <name> is ASCII up to 20 characters

such as “PT100”

CONFigure:TABLe:NAME? Returns the number, 1 to 4 ,of currently selected table

CONFigure:TABLe:ERASE Erases all rows in the table

CONFigure:TABLe:ADD <user_value,resistance_value> Adds a row to the end of table show-

ing user value and resistance value in ohms.

example CONF:TABL:ADD 20, 95 means that if the table is selected and the operator enters 20

from the front panel the output will be set to 90 Ω.

CONFigure:TABLe:ADD? Returns the last entry in the table

CONFigure:TABLe:DISPlay? Returns all data in the table

Example of information returned
PT100
20, 95

CONFigure:TABLe:UNIT <Unit> Set units for tables up to 8 ASCII characters
As an example “C” could be send for Celsius or “F” for Fahrenheit

CONFigure:TABLe:UNIT? Returns ASCII string representing the units

APPENDIX B54

PRS-330 Series

APPENDIX B

55