Fluke RUSKA 7050 User manual

PN 3952343
November 2010
© 2010 Fluke Corporation. All rights reserved. Printed in USA. Specifications are subject to change without notice.
All product names are trademarks of their respective companies.
RUSKA 7050, 7050i &
7050LP
Precision Pressure Indicator
Users Manual

LIMITED WARRANTY AND LIMITATION OF LIABILITY
Each Fluke product is warranted to be free from defects in material and workmanship under normal use and
service. The warranty period is one year and begins on the date of shipment. Parts, product repairs, and
services are warranted for 90 days. This warranty extends only to the original buyer or end-user customer of
a Fluke authorized reseller, and does not apply to fuses, disposable batteries, or to any product which, in
Fluke's opinion, has been misused, altered, neglected, contaminated, or damaged by accident or abnormal
conditions of operation or handling. Fluke warrants that software will operate substantially in accordance
with its functional specifications for 90 days and that it has been properly recorded on non-defective media.
Fluke does not warrant that software will be error free or operate without interruption.
Fluke authorized resellers shall extend this warranty on new and unused products to end-user customers
only but have no authority to extend a greater or different warranty on behalf of Fluke. Warranty support is
available only if product is purchased through a Fluke authorized sales outlet or Buyer has paid the
applicable international price. Fluke reserves the right to invoice Buyer for importation costs of
repair/replacement parts when product purchased in one country is submitted for repair in another country.
Fluke's warranty obligation is limited, at Fluke's option, to refund of the purchase price, free of charge repair,
or replacement of a defective product which is returned to a Fluke authorized service center within the
warranty period.
To obtain warranty service, contact your nearest Fluke authorized service center to obtain return
authorization information, then send the product to that service center, with a description of the difficulty,
postage and insurance prepaid (FOB Destination). Fluke assumes no risk for damage in transit. Following
warranty repair, the product will be returned to Buyer, transportation prepaid (FOB Destination). If Fluke
determines that failure was caused by neglect, misuse, contamination, alteration, accident, or abnormal
condition of operation or handling, including overvoltage failures caused by use outside the product’s
specified rating, or normal wear and tear of mechanical components, Fluke will provide an estimate of repair
costs and obtain authorization before commencing the work. Following repair, the product will be returned to
the Buyer transportation prepaid and the Buyer will be billed for the repair and return transportation charges
(FOB Shipping Point).
THIS WARRANTY IS BUYER'S SOLE AND EXCLUSIVE REMEDY AND IS IN LIEU OF ALL OTHER
WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY IMPLIED WARRANTY
OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. FLUKE SHALL NOT BE LIABLE
FOR ANY SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES OR LOSSES,
INCLUDING LOSS OF DATA, ARISING FROM ANY CAUSE OR THEORY.
Since some countries or states do not allow limitation of the term of an implied warranty, or exclusion or
limitation of incidental or consequential damages, the limitations and exclusions of this warranty may not
apply to every buyer. If any provision of this Warranty is held invalid or unenforceable by a court or other
decision-maker of competent jurisdiction, such holding will not affect the validity or enforceability of any other
provision.
Fluke Corporation
P.O. Box 9090
Everett, WA 98206-9090
U.S.A.
Fluke Europe B.V.
P.O. Box 1186
5602 BD Eindhoven
The Netherlands
11/99
To register your product online, visit register.fluke.com

7050 – Change Language
Hold key for 5 seconds
mode
enter

i
Table of Contents
Chapter Title Page
1 General Information ............................................................................ 1-1
Introduction............................................................................................ 1-1
How to Contact Fluke ............................................................................ 1-1
Safety Information ................................................................................. 1-1
Safety Summary ................................................................................ 1-1
Keep Away from Live Circuits............................................................ 1-2
Do Not Service or Adjust Alone ......................................................... 1-2
Resuscitation ..................................................................................... 1-2
Electro Static Discharge Sensitive Parts ........................................... 1-2
Compressed Gas............................................................................... 1-2
Personal Protective Equipment ......................................................... 1-2
Inert Gases ........................................................................................ 1-2
Symbols Used in this Manual ................................................................ 1-2
General Information............................................................................... 1-3
Features ................................................................................................ 1-3
Fused-Quartz Bourdon Tube Technology ......................................... 1-3
Mercury-Free ..................................................................................... 1-3
NIST Traceability ............................................................................... 1-3
Universal Power Supply .................................................................... 1-3
Friendly Display ................................................................................. 1-4
Adjustable Pressure Display.............................................................. 1-4
Ease of Operation.............................................................................. 1-4
Modular Design ................................................................................. 1-4
Attractive Desktop Packaging............................................................ 1-4
Power-On Self Test ........................................................................... 1-4
Ease of Calibration ............................................................................ 1-4
Automatic Zero Adjust ....................................................................... 1-4
Automatic Head Correction ............................................................... 1-4
Choice of Medium.............................................................................. 1-4
Choice of Display Units ..................................................................... 1-4
Communications Interface................................................................. 1-5
Standard Equipment and Options ......................................................... 1-5
2 Theory of Operation ............................................................................ 2-1

RUSKA 7050, 7050i & 7050LP
Users Manual
ii
Introduction............................................................................................ 2-1
Power Supply ........................................................................................ 2-1
Electronics Module ................................................................................ 2-2
Back-Plane Board.............................................................................. 2-2
Microprocessor Board ....................................................................... 2-2
IEEE-488 Interface ............................................................................ 2-3
Front Panel ........................................................................................ 2-3
Pneumatics Module............................................................................... 2-3
Measure Mode Pneumatics............................................................... 2-5
Reference Port .............................................................................. 2-5
Test Port ........................................................................................ 2-5
Transducer Module ............................................................................... 2-6
Quartz Bourdon Tube Sensor............................................................ 2-6
Sensor Board..................................................................................... 2-7
Linearization Term............................................................................. 2-7
Auxiliary Sensors............................................................................... 2-7
Case Reference Vacuum Sensor ...................................................... 2-8
Software ................................................................................................ 2-8
Software Safety Controls................................................................... 2-8
Oven Control ..................................................................................... 2-8
Pressure Reading and Correction ..................................................... 2-9
Zero Coefficients ........................................................................... 2-9
Range Coefficients ........................................................................ 2-9
3 Installation ........................................................................................... 3-1
Introduction............................................................................................ 3-1
Unpacking the PPI................................................................................. 3-1
Cautions ................................................................................................ 3-2
Powering Up the PPI ............................................................................. 3-2
Observing the PPI’s Full Scale Rating................................................... 3-3
Pneumatic Connections ........................................................................ 3-3
Test Port ............................................................................................ 3-3
Reference Port .................................................................................. 3-3
4 Local Operation ................................................................................... 4-1
Introduction............................................................................................ 4-1
Numeric Keypad ................................................................................ 4-1
Function Keys.................................................................................... 4-1
Rotary Knob....................................................................................... 4-1
Cancel, Previous ............................................................................... 4-2
Tutorial .................................................................................................. 4-3
Selecting Language........................................................................... 4-4
Selecting Mode of Operation ............................................................. 4-4
Instruments with the Barometric Reference Option....................... 4-4
True Absolute with Vacuum Reference Option ............................. 4-5
Main Menu............................................................................................. 4-5
Menu ..................................................................................................... 4-5
Menu | Setup ..................................................................................... 4-6
Menu | Setup — Limits .................................................................. 4-6
Menu | Setup — User .................................................................... 4-7
Menu | Setup — Units.................................................................... 4-9
Menu | Setup — Remote ............................................................... 4-10
Menu | Setup — System................................................................ 4-10
Menu | Calibrate ................................................................................ 4-12

Contents (continued)
iii
Calibration Password..................................................................... 4-12
Zeroing .......................................................................................... 4-12
Menu | Test........................................................................................ 4-13
Menu | Test — Self Test................................................................ 4-13
Menu | Test — Remote Test.......................................................... 4-13
Menu | Test — Shop1.................................................................... 4-14
Menu | Display................................................................................... 4-14
Menu | Display — Blank .................................................................... 4-14
5 Remote Operation ............................................................................... 5-1
Capabilities............................................................................................ 5-1
IEEE-488 ........................................................................................... 5-1
RS-232 .............................................................................................. 5-2
Remote/Local Operation ....................................................................... 5-2
Configuration ......................................................................................... 5-2
Device Messages .................................................................................. 5-3
SCPI Command Format .................................................................... 5-3
SCPI Response Format..................................................................... 5-3
ANSI/IEEE 488.2-1987 Command Summary.................................... 5-4
SCPI Command Summary ................................................................ 5-4
Example SCPI Commands................................................................ 5-6
SCPI Status Registers....................................................................... 5-6
6005 Interface Panel Emulation ............................................................ 5-8
Serial Operation .................................................................................... 5-8
Druck DPI-510 Emulation Command Summary .................................... 5-8
Supported Commands....................................................................... 5-8
Response Formats ............................................................................ 5-9
Reset Conditions ............................................................................... 5-9
Keyboard Entry.................................................................................. 5-9
Notes ................................................................................................. 5-10
Format ........................................................................................... 5-10
Zeroing .......................................................................................... 5-10
Rate ............................................................................................... 5-10
Units .............................................................................................. 5-10
Sample Program ................................................................................... 5-11
6 Maintenance......................................................................................... 6-1
Introduction............................................................................................ 6-1
Observing the Software Version Number .............................................. 6-1
Preventive Maintenance........................................................................ 6-1
Initiating the PPI’s Self Test............................................................... 6-1
Removing the PPI’s Cover ................................................................ 6-2
Moisture Filter.................................................................................... 6-3
Particle Filters.................................................................................... 6-3
Vacuum Pumps ................................................................................. 6-3
Processor Battery .............................................................................. 6-3
Calibration ............................................................................................. 6-3
Calibration Instructions ...................................................................... 6-4
Preparation .................................................................................... 6-4
Storing the Coefficients ................................................................. 6-7
Vacuum (Negative Gauge) Calibrations ............................................ 6-7
RPT Calibration — Simulated Absolute............................................. 6-8
Editing the Calibration Coefficients.................................................... 6-9
Zeroing .............................................................................................. 6-10

RUSKA 7050, 7050i & 7050LP
Users Manual
iv
Gauge and Vacuum (Negative Gauge) Instruments ..................... 6-10
Absolute Instruments..................................................................... 6-11
RPT — Simulated Absolute Instruments ....................................... 6-12
Sensor Photocell Zeroing ...................................................................... 6-12
Fan Operation ....................................................................................... 6-15
System Software Update Procedure ..................................................... 6-16
Replacement Parts................................................................................ 6-16
7 Preparation for Storage & Shipment ................................................. 7-1
Introduction............................................................................................ 7-1
Disconnecting the PPI ........................................................................... 7-1
Packing Instructions .............................................................................. 7-1
Shipping Instructions ............................................................................. 7-3
Appendices
A Summary of Specifications .............................................................. A-1
B Summary of Error Messages........................................................... B-1

v
List of Tables
Table Title Page
1-1. Symbols..................................................................................................... 1-3
1-2. RUSKA 7050 PPI - Options List ................................................................ 1-5
2-1. Conversion Factors ................................................................................... 2-3
3-1. General Specifications and Parameters.................................................... 3-2
6-1. Electronics Self Test.................................................................................. 6-2
6-2. RUSKA 7050 PPI - Parts List .................................................................... 6-16

RUSKA 7050, 7050i & 7050LP
Users Manual
vi

vii
List of Figures
Figure Title Page
2-1. PPI Block Diagram .................................................................................... 2-1
2-2. RUSKA 7050 PPI Gauge Pneumatics Diagram 5 to 2500 psig
(34 kPa to 17.2 MPa) Full Scale Ranges .................................................. 2-4
2-3. RUSKA 7050 PPI Absolute Pneumatics Diagram to 50 PSIA
(340 kPa) FS ............................................................................................. 2-5
2-4. Shaft/Magnet Section ................................................................................ 2-6
2-5. Photocell/Light Spot .................................................................................. 2-7
2-6. Menu | Display-Menu ................................................................................ 2-9
3-1. RUSKA 7050 Back Panel.......................................................................... 3-3
4-1. RUSKA 7050 Front Panel ......................................................................... 4-1
4-2. Menu Tree ................................................................................................. 4-2
4-3. Main Menu................................................................................................. 4-3
4-4. Units Menu ................................................................................................ 4-3
4-5. Mode Menu ............................................................................................... 4-4
4-6. Main Menu Screen .................................................................................... 4-5
4-7. Menu Key - Functions ............................................................................... 4-5
4-8. Menu | Setup - Menu................................................................................. 4-6
4-9. Menu | Setup | Limits - Menu..................................................................... 4-6
4-10. Menu | Setup | User - Menu ...................................................................... 4-7
4-11. Menu | Setup | Units - Menu...................................................................... 4-9
4-12. Menu | Setup | Units | Edit Name - Menu .................................................. 4-9
4-13. Menu | Setup | Remote - Menu ................................................................. 4-10
4-14. Menu | Setup | System - Menu .................................................................. 4-11
4-15. Menu | Test - Menu ................................................................................... 4-13
4-16. Menu | Test | Remote - GPIB Menu & Serial1 Menu................................. 4-14
4-17. Menu l Display - Menu............................................................................... 4-14
6-1. Menu | Test | Self - Menu .......................................................................... 6-2
6-2. Menu | Calibration ..................................................................................... 6-4
6-3. Vacuum Calibration ................................................................................... 6-7
6-4. Zeroing Menu ............................................................................................ 6-10
6-5. Zero Set..................................................................................................... 6-11
6-7. Centering the Photocell ............................................................................. 6-13
6-8. Correct Adjustment of Photocell Centering Bar......................................... 6-13
6-9. Photocell Location ..................................................................................... 6-14
6-10. Menu | Test | Shop 1 - Menu..................................................................... 6-15

RUSKA 7050, 7050i & 7050LP
Users Manual
viii
7-1. Packing the PPI......................................................................................... 7-3

1-1
Chapter 1
General Information
Introduction
This manual contains operation and routine and preventive maintenance instructions for
the RUSKA 7050, RUSKA 7050i and RUSKA 7050LP Precision Pressure Indicator (PPI)
manufactured by Fluke. This section of the manual provides general information about
the PPI and presents its features and options.
How to Contact Fluke
To order accessories, receive operating assistance, or get the location of the nearest Fluke
distributor or Service Center, call:
•Technical Support USA: 1-800-99-FLUKE (1-800-993-5853)
•Calibration/Repair USA: 1-888-99-FLUKE (1-888-993-5853)
•Canada: 1-800-36-FLUKE (1-800-363-5853)
•Europe: [phone]
•China: [phone]
•Japan: [phone]
•Singapore: [phone]
•Anywhere in the world: [phone]
Or, visit Fluke's website at www.fluke.com.
To register your product, visit http://register.fluke.com.
To view, print, or download the latest manual supplement, visit
http://us.fluke.com/usen/support/manuals.
Safety Information
Safety Summary
The following are general safety precautions that are not related to any specific
procedures and do not appear elsewhere in this publication. These are recommended
precautions that personnel must understand and apply during equipment operation and
maintenance to ensure safety and health and protection of property.

RUSKA 7050, 7050i & 7050LP
Users Manual
1-2
Keep Away from Live Circuits
Operating personnel must at all times observe safety regulations. Do not replace
components or make adjustments inside the equipment with the voltage supply connected.
Under certain conditions, dangerous potentials may exist when the power control is in the
off position due to charges retained by capacitors. To avoid injuries, always remove
power from, discharge, and ground a circuit before touching it.
Do Not Service or Adjust Alone
Do not attempt internal service or adjustment unless another person capable of rendering
aid and resuscitation is present.
Resuscitation
Personnel working with or near dangerous voltages shall be familiar with modern
methods of resuscitation. Such information may be obtained from your local American
Medical Association.
Electro Static Discharge Sensitive Parts
WCaution
Electrostatic discharge sensitive (ESDS) is applied to low
power, solid-state parts which could be damaged or destroyed
when exposed to discharges of static electricity. Maintenance
personnel are often not aware that an ESDS part has been
damaged or destroyed because electrostatic discharges at
levels less than 4,000 volts cannot be seen, felt, or heard.
Compressed Gas
Use of compressed gas can create an environment of propelled foreign matter. Pressure
system safety precautions apply to all ranges of pressure. Care must be taken during
testing to ensure that all pneumatic connections are properly and tightly made prior to
applying pressure. Personnel must wear eye protection to prevent injury.
Personal Protective Equipment
Wear eye protection approved for the materials and tools being used.
Inert Gases
Operation of pressure equipment may be accompanied by the discharge of inert gases to
the atmosphere. The result is a reduction of oxygen concentration. Therefore, it is
strongly suggested that exhaust gases not be trapped in the work area.
Symbols Used in this Manual
In this manual, a Warning identifies conditions and actions that pose a hazard to the user.
A Caution identifies conditions and actions that may damage the Precision Pressure
Indicator (PPI).
Symbols used on the Precision Pressure Indicator (PPI) and in this manual are explained
in Table 1-1.

General Information
General Information 1
1-3
Table 1-1. Symbols
Symbol Description
JEarth Ground
WImportant Information: refer to manual
XShock Hazard
~Do not dispose of this product as unsorted
municipal waste. Go to Fluke’s website for
recycling information.
P
This equipment meets the requirements
of all relevant European safety directives.
The equipment carries the CE mark.
General Information
WWarning
If the equipment is used in a manner not specified by the
manufacturer, the protection provided by the equipment may be
impaired.
The AC main plug, switch and power cord shall remain readily
accessible for the operation.
The RUSKA 7050 Precision Pressure Indicator uses force-balanced, fused-quartz
Bourdon tube technology to provide the precise measurement of pressure.
In Measure mode, the PPI measures pressure. Typically, Measure mode applications are
found in research laboratories, wind tunnel testing, power plant testing, and bubbler tank
volume accountancy systems. It is also used to monitor barometric pressures, vacuum
systems, and differential pressure devices.
Features
The following features are available on all RUSKA 7050 PPIs.
Fused-Quartz Bourdon Tube Technology
(5 - 2500 psi full scale ranges), RUSKA’s force-balanced, fused-quartz Bourdon tube
sensor makes use of the stability, high elasticity, low hysteresis, and excellent fatigue
strength of fused quartz. This time-proven technology eliminates the need for gear trains,
bearings, shafts, and other moving parts that can wear out or introduce hysteresis or
deadband into the process.
Mercury-Free
All components in the PPI are mercury-free.
NIST Traceability
All PPIs are calibrated per ANSI/NCSL Z-540-1-1994 using RUSKA deadweight gauges
that are directly traceable to the National Institute of Standards and Technology (NIST).
Universal Power Supply
The PPI’s universal power supply accepts AC voltages between 100-120 VAC and
220-240 VAC. To “reconfigure” the PPI for use in another country, the user simply
changes the power cord.

RUSKA 7050, 7050i & 7050LP
Users Manual
1-4
Friendly Display
The PPI’s color active matrix TFT display combines a bright, low-glare readout with a
wide viewing angle. During normal operation, the measured pressure is easily visible
from a distance of 10 feet (3 meters).
Adjustable Pressure Display
The pressure display may be adjusted to show one decimal greater than or less than the
default resolution.
Ease of Operation
An intuitive, menu-driven interface makes the PPI easy to use. Frequently used selections
such as the units of measure are restored to memory each time the PPI powers up.
Modular Design
The sensing element, pneumatics, electronics, and user interface are separated into
modules, making maintenance faster and easier.
Attractive Desktop Packaging
A sturdy aluminum case houses all of the PPI’s pneumatics, electronics, and user controls.
With the optional rack mount kit, this standard 19" EIA chassis fits easily into a rack
mount system.
Power-On Self Test
Upon power-up, the PPI quickly tests its hardware and software. After the PPI completes
this test, the user can select more extensive self-tests for the pneumatics and electronics.
Ease of Calibration
Calibration may be performed either remotely or entirely from the front panel. No
disassembly is required, and there are no potentiometers to tune. On single sensor units,
only a three-point calibration is required to fully characterize the instrument. On
instruments that integrate multiple ranges such as the 7050i and 7050LP, additional
calibration points are required.
Automatic Zero Adjust
At the user’s request, the PPI’s software automatically performs the zero adjustment, with
no potentiometers to tune.
Automatic Head Correction
The PPI automatically corrects for head pressure between the PPI and the device under
test (DUT), taking into account the density of the test gas; e.g., air or nitrogen.
Choice of Medium
Although the PPI is not sensitive to the type of gas used within the system, the user can
select either instrumentation air or nitrogen, allowing the PPI to automatically make
pressure head corrections.
Choice of Display Units
Standard units include inHg at 0 °C and 60 °F, kiloPascals, bars, psi, inH2O at 4 °C,
20 °C, and 25 °C, kilograms per square centimeter, mmHg, cmHg at 0 °C, and cmH2O at
4 °C. Altitude and airspeed units include feet, meters, knots, and kilometers per hour. In
addition to these predefined units, four user-defined units are programmable.

General Information
Standard Equipment and Options 1
1-5
Communications Interface
The PPI includes standard RS-232 serial and IEEE-488 interfaces. The user’s computer
communicates with the PPI through the Standard Commands for Programmable
Instruments (SCPI) protocol. The 7050 shares the same protocol as the RUSKA 7010,
7215, 7215i and 7215xi, therefore, it can operate from software written for any of these
products. The PPI can also be configured to accept existing software written for the
RUSKA Series 6000 Digital Pressure Gauge/Controller or the Druck model 510.
NVLAP Accredited Calibrations
Fluke received formal accreditation from the National Voluntary Laboratory
Accreditation Program (NVLAP) which is administrated by the National Institute of
Standards and Technology (NIST). NVLAP has assigned Fluke laboratory code
200491-0 to indicate that our accredited calibration services are in compliance with all
relevant requirements of ISO/IEC 17025:2005. Accredited calibration certifications are
now provided standard by Fluke Calibration.
Standard Equipment and Options
A standard PPI includes this manual and a power cord. Although the standard PPI is fully
functional with just these items and the appropriate pressure and vacuum supplies, the
following options are also available.
Additional Power Cords: Additional power cords are available for most countries.
All options are summarized in 1-2. To order these items, please contact Fluke Calibration
Sales in the U.S. at [phone].
Table 1-2. RUSKA 7050 PPI - Options List
Option Part Number
LabView Driver (National Instruments) Downloadable from World Wide Web
Rack Mount Kit - Cabinets 18-24 inches deep 3879677
Vacuum Pump, 115/230 VAC 50/60 Hz 3917819
Power Cord, USA and Canada 284174
Power Cord, Central Europe 769422
Power Cord, India 782771
Power Cord, Japan 3898323
Power Cord, Australia/New Zealand 658641

RUSKA 7050, 7050i & 7050LP
Users Manual
1-6

2-1
Chapter 2
Theory of Operation
Introduction
The PPI’s power supply, electronics, pneumatics, and sensor combine to form a complete,
stand-alone, measure and control instrument. This section of the manual describes the
PPI’s component modules and provides a general discussion of each.
Primary Transducer Module
SENSOR SENSOR
BOARD
CASE
TUBE
Photo
Sensor
AC
POWER
FRONT
PANEL
POWER
SUPPLY
BACKPLANE
BOARD
MICROPROCESSOR
BOARD
IEEE
CARD
Electronic Module
RS -232
IEEE-488
glc02.eps
Figure 2-1. PPI Block Diagram
Power Supply
The PPI’s universal power supply accepts AC voltages from 100-120 VAC and 220-240
VAC at 50/60Hz. This quad–output supply produces +5 VDC, +/-12 VDC, and 24 VDC
which are distributed to the Control and Backplane Boards.

RUSKA 7050, 7050i & 7050LP
Users Manual
2-2
Electronics Module
Back-Plane Board
The Back-plane Board is used to interconnect all of the plug-in electronic boards and
distribute power. The Microprocessor Board, the Digital Control Board, and the
IEEE-488 Interface all plug into the Back-plane Board. The Front Panel communicates
with the Microprocessor Board via cables. The Sensor Board communicates with the
Microprocessor board through an internal RS-485 serial communication bus.
Microprocessor Board
All of the PPI’s software resides in nonvolatile, programmable, read-only memory (Flash
EPROM) on the Microprocessor Board, which plugs directly into the Back-plane Board.
This software contains all of the instructions that operate the PPI, as well as the
conversion factors that the PPI uses to translate the internal pressure unit-of-measure of
kPa into the units selected by the user. These factors are given in Table 2-1.
Data that is subject to change after the PPI leaves the factory are held in electrically
erasable, programmable, read-only memory (EEPROM). This includes the current units
of measure, the coefficients from the zeroing process, the current pressure medium,
calibration coefficients, and the conversion factors for the four user-defined units of
measure.
When the PPI powers up, its software is loaded into random access memory (RAM), also
on the Microprocessor Board. At the same time, the values stored in EEPROM Board are
restored to memory.
Another important component on the Microprocessor Board is the lithium battery. The
battery continuously updates the PPI’s date and time, even when the unit is powered
down. This battery has a varying life. If the instrument is left on 24 hours a day, it may
last 5 to 10 years. If the instrument is stored, it may only last one year.
The Microprocessor Board also supports the RS-232 serial interface that allows the user’s
computer to communicate with the PPI.