Omega PX2088 User manual

User’s Guide
Model PX2088 Pressure Transmitter
http://www.omega.com
e-mail: [email protected]
PX2088
Pressure Transmitter

OMEGAnet®On-Line Service Internet e-mail
http://www.omega.com [email protected]
Servicing North America:
USA: One Omega Drive, Box 4047
ISO 9001 Certified Stamford, CT 06907-0047
Tel: [phone] FAX: [phone]
e-mail: [email protected]
Canada: 976 Bergar
Laval (Quebec) H7L 5A1
Tel: [phone] FAX: [phone]
e-mail: [email protected]
For immediate technical or application assistance:
USA and Canada: Sales Service: 1-800-826-6342 / 1-800-TC-OMEGASM
Customer Service: 1-800-622-2378 / 1-800-622-BESTSM
Engineering Service: 1-800-872-9436 / 1-800-USA-WHENSM
TELEX: 996404 EASYLINK: 62968934 CABLE: OMEGA
Mexico and
Latin America: Tel: [phone] FAX: [phone]
En Espan˜ol: (95) 203-359-7803 e-mail: [email protected]
Servicing Europe:
Benelux: Postbus 8034, 1180 LA Amstelveen, The Netherlands
Tel: [phone] FAX: [phone]
Toll Free in Benelux: 0800 0993344
e-mail: [email protected]
Czech Republic: ul. Rude armady 1868, 733 01 Karvina-Hranice
Tel: [phone] FAX: [phone]
Toll Free: 0800-1-66342 e-mail: [email protected]
France: 9, rue Denis Papin, 78190 Trappes
Tel: [phone] FAX: [phone]
Toll Free in France: 0800-4-06342
e-mail: [email protected]
Germany/Austria: Daimlerstrasse 26, D-75392 Deckenpfronn, Germany
Tel: [phone] FAX: [phone]
Toll Free in Germany: 0130 11 21 66
e-mail: [email protected]
United Kingdom: One Omega Drive, River Bend Technology Centre
ISO 9002 Certified Northbank, Irlam, Manchester
M44 5EX, England
Tel: [phone] FAX: [phone]
Toll Free in the United Kingdom: 0800-488-488
e-mail: [email protected]
It is the policy of OMEGA to comply with all worldwide safety and EMC/EMI regulations that apply. OMEGA is constantly pursuing certification of
its products to the European New Approach Directives. OMEGA will add the CE mark to every appropriate device upon certification.
The information contained in this document is believed to be correct, but OMEGA Engineering, Inc. accepts
no liability for any errors it contains, and reserves the right to alter specifications without notice.
WARNING: These products are not designed for use in, and should not be used for, patient-connected applications.

Table of Contents
i
SECTION 1
Introduction
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Safety Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Safety Notice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Models Covered . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Using This Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
SECTION 2
Commissioning the Smart Transmitter
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Safety Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Commission: On the Bench or In the Loop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Set up the Transmitter and the Communicator . . . . . . . . . . . . . . . . . . . . . 2-2
Review Configuration Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Check Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Process Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Basic Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Tag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Output Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Rerange . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
Damping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Detailed Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Meter Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Burst Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Save, Recall, or Clone Configuration Data . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
Enable or Disable Local Span and Zero Buttons . . . . . . . . . . . . . . . . . . . . . 2-7
Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
Calibration Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
Sensor Trim . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
Output Trim . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11
Diagnostics and Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-12
Multidrop Communication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-13
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ii
SECTION 3
Commissioning the Analog Transmitter
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Safety Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Commission: On the Bench or In the Loop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Test Terminals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Zero and Span Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
Selector Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
Potentiometer Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
Setting the Zero . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
Setting the Span . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
SECTION 4
Installation
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
Safety Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
Installation Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
Model PX2088 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
Wiring Connections PX2088 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8
Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10
Failure Mode and Security Jumpers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-11
Failure Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-11
Transmitter Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-12
Zero and Span Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-12
Rerange Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13
SECTION 5
Troubleshooting
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2
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iii
SECTION 6
Spare Parts and Ordering
Spare Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1
SECTION 7
LCD Meter
LCD Meter for Smart Transmitters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1
Diagnostic Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2
LCD Meter for Analog Transmitters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-4
Diagnostic Message Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-5
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-5
Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6
Positioning the Decimal Point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-7
Scaling the Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-7
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iv
APPENDIX A
Model HC275 HART
Communicator
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1
Safety Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1
Menu Tree . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-2
Fast Key Sequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-3
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SECTION
1-1
1
1Introduction
OVERVIEW
This section contains general transmitter safety information, a brief description of
each model covered in this manual, and a summary of each of each section.
SAFETY MESSAGES
Procedures and instructions in this manual may require special precautions to
ensure the safety of the personnel performing the operations.
SAFETY NOTICE
The following performance limitations may inhibit efficient or safe operation. Critical
applications should have appropriate diagnostic and backup systems in place.
Pressure transmitters contain an internal fill fluid. It is used to transmit the process pressure
through the isolating diaphragms to the pressure sensing element. In rare cases, oil leak paths
in oil-filled pressure transmitters can be created. Possible causes include: physical damage to
the isolator diaphragms, process fluid freezing, isolator corrosion due to an incompatible
process fluid, etc.
A transmitter with an oil fill fluid leak can continue to perform normally for a period of time.
Sustained oil loss will eventually cause one or more of the operating parameters to exceed
published specifications while a small drift in operating point output continues. Symptoms of
advanced oil loss and other unrelated problems include:
nSustained drift rate in true zero and span or operating point output or both
nSluggish response to increasing or decreasing pressure or both
nLimited output rate or very nonlinear output or both
nChange in output process noise
nNoticeable drift in operating point output
nAbrupt increase in drift rate of true zero or span or both
nUnstable output
nOutput saturated high or low
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1-2
1 MODELS COVERED
Model PX2088 Smart and Analog Absolute or Gage Pressure Transmitter
measures absolute or gage pressure ranges from 0–1 to 0–4,000 psi
(0–6.9 to 0–27579 kPa) using a patented piezoresistive silicon sensor.
Mounts directly to the process pipe or to the optional mounting bracket.
USING THIS MANUAL
This manual provides information for the Omega Model PX2088
Pressure Transmitter. It is organized into the following sections:
Section 2 Commissioning the Smart Transmitter
This section provides information on commissioning and operating the Model PX2088
Smart Pressure Transmitter. Information is also included on software functions,
configuration parameters, and on-line variables.
Section 3 Commissioning the Analog Transmitter
This section provides information on commissioning and operating the Model PX2088
Analog Pressure Transmitter.
Section 4 Installation
This section provides installation procedures, wiring diagrams, and information
about transmitter load limitations and power supply requirements.
Section 5 Troubleshooting
This section provides basic troubleshooting suggestions to help solve the most
common operating problems.
Section 6 Reference Data
This section provides reference data including ambient temperature effects, spare
parts, and typical transmitter model structures.
Secton 7 LCD Meter
This section provides installation and operation information for the optional LCD
Meter.
Appendix B HART Communicator
menu tree and fast key sequences for HART Communicator
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SECTION
2-1
EN
2Commissioning the Smart
Transmitter
OVERVIEW
This section contains information regarding commissioning the transmitter.
Commissioning involves reviewing configuration data, setting the 4 and 20 mA
points, configuring the transmitter to recognize accessories such as a LCD meter,
and testing the transmitter output.
SAFETY MESSAGES
This section contains procedures that require connecting a communicator to the
transmitter, or making connections in an explosive atmosphere. The following safety
messages apply to all procedures throughout this section requiring cover removal
and communicator connection to the transmitter terminal block. Keep the following
safety messages in mind whenever you perform an operation requiring cover
removal or the connection of a communicator to a measurement loop.
Warnings
Explosions could result in death or serious injury:
nDo not remove the transmitter covers in explosive atmospheres
when the circuit is alive.
nBefore connecting a HART-based communicator in an explosive atmosphere,
make sure the instruments in the loop are installed in accordance with
intrinsically safe or non-incendive field wiring practices.
nBoth transmitter covers must be fully engaged to meet
explosion-proof requirements.
High voltage that may be present on leads could cause electrical shock:
nAvoid contact with leads and terminals.
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2-2
EN COMMISSION: ON THE BENCH OR IN THE LOOP
Commission the Model PX2088 Smart Transmitter before or after installation.
It may be useful to commission the transmitter on the bench before
installation to ensure proper operation, to familiarize yourself with transmitter
functionality, and to avoid exposing the transmitter electronics to the plant
environment. Commissioning consists of reviewing configuration data, setting
output units, setting the 4 and 20 mA points, configuring the transmitter for any
non-standard accessories or functions, and testing the transmitter output.
Set up the Transmitter and the Communicator
To configure the transmitter on the bench, connect the transmitter and the
communicator as shown in Figure 2-1. To power the transmitter you will need a
power supply capable of providing 10.5 to 36.0 V dc and a meter to measure output
current. Toenable communication, aresistanceofatleast250 ohms must be present
between the communicator loopconnection and the power supply. You can connect the
communicator leads at any termination point in the signal loop, but it is most
convenient to connect them to the terminals labeled “COMM” on the terminal block.
After you connect the bench equipment as shown in Figure 2-1, turn on the
communicator by pressing the ON/OFF key. The communicator will search for a
HART-compatible device and will indicate that the connection is made. If the
connection is not made, the communicator will indicate that no device was found.
FIGURE 2-1. Connecting a Communicator to a Transmitter Loop
If the communicator lacks the device driver for the PX2088 Smart, the transmitter will
be identified as “GENERIC” by the communicator. Basic configuration functions are
still possible, but many advanced configuration functions are not possible when the
communicator is in this mode. Contact Omega customers service for assistance
in obtaining the PX2088 Smart device driver for the HART Communicator.
Power
Supply
RL≥ 250 V
The signal loop may be grounded
at any single point in the loop, or
may be left ungrounded
2088S-2088C02C
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2-3
EN
FIGURE 2-2. HART Communicator ScreenWithout Model PX2088 Smart Device Driver.
REVIEW CONFIGURATION DATA
Review all of the factory-set configuration data to ensure that is reflects the needs of
your application before operating the transmitter in an actual installation.
Review
Review the transmitter configuration parameters set at the factory to ensure
accuracy and compatibility with your particular application. After activating the
review function, scroll through the data list to check each variable. Refer to “Basic
Setup” in this section of the manual if a change to the transmitter configuration data
is necessary.
CHECK OUTPUT
Before performing other transmitter on-line operations, review the digital output
parameters to ensure that the transmitter is operating properly and is configured to
the appropriate process variables.
Process Variables
The process variables for the Model PX2088 Smart provide the transmitter output,
and are continuously updated. The Process Variable menu displays the following
process variables:
nPressure
nPercent Range
nAnalog Output
HART Fast Keys 1, 5
HART Fast Keys 1, 1
Generic
Online
1Device Setup
2PV 100.00 inH2O
3AO 20.00 mA
4LRV0.00 inH2O
5URV100.00 inH2O
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2-4
EN BASIC SETUP
From the Basic Setup menu you can configure the transmitter for certain basic
variables. In many cases, all of these variables are pre-configured at the factory.
Configuration may be required if your transmitter is not configured or if the
configuration variables need revision.
Tag
The Tagvariable is the easiest way to identify and distinguish between transmitters
in multi-transmitter environments. Use this variable to label transmitters
electronically according to the requirements of your application. The tag you define
is automatically displayed when a HART-based communicator establishes contact
with the transmitter at power-up. The tag may be up to eight characters long and
has no impact on the primary variable readings of the transmitter.
Output Units
The Unit command sets the desired primary variable units. Set the transmitter
output to one of the following engineering units:
ninH2O
ninHg
nftH2O
nmmH2O
npsi
nbar
nmbar
nInH2O @ °4 C
NOTE
Output units is the only variable which must be sent separately from all other
variable configurations. After changing units, press SEND (F2) so the
microprocessor will recalculate the associated variables (4–20 mA points, for
example). The Model PX2088 Smart recalculates all variables that depend on units.
After the transmitter recalculates the variables, you may change any of the
remaining parameters.
HART Fast Keys 1, 3, 1
HART Fast Keys 1, 3, 3
ng/cm2
nkg/cm2
nPa
nkPa
ntorr
natm
nmmH2O @ °4 C
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2-5
EN
Rerange
The Range Values command sets the 4 and 20 mA points (lower and upper range
values). Setting the range values to the limits of expected readings maximizes
transmitter performance; the transmitter is most accurate when operated within the
expected pressure ranges for your application. In practice, you may reset the
transmitter range values as often as necessary to reflect changing process
conditions.
You may use one of three methods to rerange the transmitter. Each method is
unique; examine all three closely before deciding which method to use.
NOTE
Regardless of the range points, the Model PX2088 Smart will measure and report all
readings within the digital limits of the sensor. For example, if the 4 and 20 mA
points are set to 0 and 10 inH2O, and the transmitter detects a pressure of 25 inH2O,
it digitally outputs the 25 in H2O reading and a 250% percent of span reading.
However, there may be up to ±5.0% error associated with output outside of the range
points.
Method 1:Rerange Using the Communicator
Reranging using only the communicator is the easiest and most popular way to
rerange the transmitter. This method changes the values of the analog 4 and 20
mA points independently without a pressure input.
To rerange using only the communicator enter the fast-key sequence above, select
1 Keypad input, and follow the on-line instructions. Or enter the values directly
from the HOME screen.
Method 2:Rerange Using the Communicator and a Pressure Source or Process
Pressure
Reranging using the communicator and a pressure source or process pressure is a
way of reranging the transmitter when specific 4 and 20 mA points are not known.
This method changes the values of the analog 4 and 20 mA points. When you set
the 4 mA point the span is maintained; when you set the 20 mA point the span
changes.
To rerange using the communicator and a pressure source or process pressure
enter the fast-key sequence above, select 2 Apply values, and follow the on-line
instructions.
Method 3:Rerange Using the Local Zero and Span Buttons
and a Pressure Source or Process Pressure
Reranging using the local zero and span adjustments and a pressure source is a
way of reranging the transmitter when specific 4 and 20 mA points are not known
or a communicator is not available. When you set the 4 mA point the span is
maintained; when you set the 20 mA point the span changes.
To rerange using the zero and span adjustments, refer to “Rerange Procedure” on
page 4-13.
HART Fast Keys 1, 3, 3
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2-6
EN Damping
The Damping command changes the response time of the transmitter to smooth
variations in output readings caused by rapid changes in input. Determine the
appropriate damping setting based on the necessary response time, signal stability,
and other requirements of the loop dynamics of your system. The default damping
value is 0.50 seconds and can be reset in fixed increments of 0.05, 0.10, 0.20, 0.40,
0.80, 1.60, 3.20, 6.40, 12.8, or 25.6 seconds.
DETAILED SETUP
Meter Setup
The Meter Type command allows you to configure the transmitter for use with an
LCD meter. Transmitters shipped without meters are set to “NONE.” Change the
meter settings as often as necessary to reflect changing process or application
conditions. To change the meter settings, and thereby configure the transmitter to
recognize the LCD meter, perform the following procedure.
1.Select 1 Device setup, 4 Detailed setup, 3 Output condition, 4 Meter options to
prepare to change the meter settings.
2.Select the appropriate variable configuration from the Meter options screen,
and press enter.
NOTE
Selecting “None” from the meter type screen will disable the meter.
3.Select SEND to download the new meter configuration information to the
transmitter.
For a more detailed description of the LCD meter features and diagnostic messages,
refer to Section 7 LCD Meter.
Burst Mode
Burst Mode sets the transmitter to maintain digital contact with a Digital Control
System that has custom software to support burst mode. When the Model PX2088
Smart is configured for burst mode, it provides faster digital communication from
the transmitter to the control system by eliminating the time required for the control
system to request information from the transmitter.
HART Fast Keys 1. 3. 6
HART Fast Keys 1,4,3,4
HART Fast Keys 1, 4, 3, 4, 3
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2-7
EN
Burst mode is compatible with use of the analog signal. Because HART®protocol
features simultaneous digital and analog data transmission, the analog value can
drive other equipment in the loop while the control system is receiving the digital
information. Burst mode applies only to the transmission of dynamic data (pressure
and temperature in engineering units, pressure in percent of range, and/or analog
output in mA or V), and does not affect the way other transmitter data is accessed.
Access to information other than dynamic transmitter data is obtained through the
normal poll/response method of HART communication. A HART-based
communicator or the control system may request any of the information that is
normally available while the transmitter is in burst mode. Between each message
sent by the transmitter, a short pause allows the HART-based communicator or a
control system to initiate a request. The transmitter will receive the request, process
the response message, and then continue “bursting” the data approximately three
times per second.
Save, Recall, or Clone Configuration Data
Data that was entered off-line can be stored in the communicator memory and
downloaded to other transmitters later. Data also can be copied from a transmitter in
order to be sent to other transmitters in a process known as “cloning”. This is
especially useful if you work with a large number of transmitters that require the
same configuration data.
Enable or Disable Local Span and Zero Buttons
The Local Keys command allows you to enable or disable the local span and zero
buttons. Disabling the local keys will prevent unauthorized reranging using the span
and zero buttons, but will not prevent reranging using the communicator. To prevent
all changes to the configuration data, use the transmitter security jumper (see
“Transmitter Security” on page 4-12).
HART Fast Keys left arrow, 3 (note)
HART Fast Keys 1, 4, 4, 1, 7
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2-8
EN CALIBRATION
Calibrating the transmitter increases the precision of your measurement system.
You may use one or more of a number of trim functions when calibrating.
To understand the trim functions, it is necessary to understand that smart
transmitters operate differently from analog transmitters. An important difference is
that smarttransmitters are factory-characterized;they are shipped with a standard
sensor curve stored in the transmitter firmware. In operation, the transmitter uses
this information to produce a process variable output, in engineering units,
dependent on the sensor input. The trim functions allow you to make corrections to
the factory-stored characterization curve by digitally altering the transmitter’s
interpretation of the sensor input.
The trim functions should not be confused with the rerange functions. Although the
rerange command matches a sensor input to a 4–20 mA output—as in conventional
calibration—it does not affect the transmitter’s interpretation of the input.
Calibration Overview
Complete calibration of the Model PX2088 Smart Pressure Transmitter involves one or
more of the following tasks:
Configure the Analog Output Parameters
nSet Process Variable Units (Page 2-3)
nRerange (Page 2-5)
nSet Output Type (Page 2-4)
nSet Damping (Page 2-6)
Calibrate the Sensor
nFull Trim (Page 2-10)
nZero Trim (Page 2-10)
Calibrate the 4–20 mA Output
nDigital to Analog Trim (Page 2-11) or
nScaled Digital to Analog Trim (Page 2-12)
Figure 2-3 illustrates the Model PX2088 Smart transmitter data flow. This data flow
can be summarized in four major steps:
1.A change in pressure is measured by a change in the sensor output (Sensor
Signal).
2.The sensor signal is converted to a digital format that can be understood by
the microprocessor (Analog-to-Digital Signal Conversion).
3.Corrections are performed in the microprocessor to obtain a digital
representation of the process input (Digital PV).
4.The Digital PV is converted to an analog value
(Digital-to-Analog Signal Conversion).
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2-9
EN
Deciding Which Trim
Procedure to Use
To decide which trim procedure to use, you must first determine whether the analog-
to-digital section or the digital-to-analog section of the transmitter electronics is in
need of calibration. To do so, refer to Figure 2-3 and perform the following procedure:
1.Connect a pressure source, a HART communicator, and an output device to
the transmitter.
2.Establish communication between the transmitter and the communicator.
3.Apply the desired 20mA point pressure (100 in H2O, for example).
4.Compare the applied pressure to the Process Variable (PV) line on the
Communicator Online Menu. If the PV reading on the communicator does not
match the applied pressure, and you are certain your test equipment is
accurate, perform a sensor trim.
5.Compare the Analog Output (AO) line on the communicator online menu to
the digital readout device. If the AO reading on the communicator does not
match the digital readout device, and you are certain your test equipment is
accurate, perform an output trim.
Sensor Trim
You can trim the sensor using either the full trim or the zero trim function. The trim
functions vary in complexity, and their use is application-dependent. Both alter the
transmitter’s interpretation of the input signal.
Microprocessor
Digital PV Digital-to-Analog
SignalConversion
Analog-to-
Digital Signal
Conversion
Transmitter Electronics Module
FIGURE 2-3. Transmitter Data Flow
with Calibration Options.
Analog Output
Sensor Signal
HART Communications
100 inH
2
O
(Transmitter Ranged 0 to 100 inH
2
O)
PX2088S:PT-4763
Online
1Device Setup
2PV 100.00 inH2O
3AO 20.00 mA
4LRV0.00 inH2O
5URV100.00 inH2O
Output Device
20.00 mA
Input Device
NOTES
1)Value on PV line should equal
the input pressure
2)Value on AO line should equal the
output device reading
1
23 4
If readings do not
match perform
sensor trim
If readings do
not match
perform
output trim
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2-10
EN A zero trim is a single-point adjustment. It is useful for compensating for mounting
position effects, and can be performed with the transmitter installed or from the
bench. Since this correction maintains the slope of the characterization curve, it
should not be used in place of a full trim over the full sensor range.
A full trim is a two-point sensor calibration where two end-point pressures are
applied, and all output is linearized between them. You should always adjust the low
trim value first to establish the correct offset. Adjustment of the high trim value
provides a slope correction to the characterization curve based on the low trim value.
The factory-established characterization curve is not changed by this procedure. The
trim values allow you to optimize performance over your specified measuring range
at the calibration temperature.
Zero Trim
To calibrate the sensor using the zero trim function, perform the following procedure.
1. Vent the transmitter and attach a communicator to the measurement loop.
2. From the communicator main menu select 1 Device setup,
2 Diagnostics and service, 3 Calibration,3 Sensor trim, 1 Zero trim to prepare
to adjust the zero trim.
NOTE
The transmitter must be within 3% of true zero (zero based) in order to calibrate
using the zero trim function.
3. Follow the commands provided by the communicator to complete the
adjustment of the zero trim.
Full Trim
To calibrate the sensor using the full trim function, perform the following procedure.
1. Assemble and power the entire calibration system including a transmitter,
communicator, power supply, pressure input source, and readout device.
NOTE
Use a pressure input source that is at least three times more accurate than the
transmitter, and allow the input pressure to stabilize for 10 seconds before entering
any values. If remote seals are used allow more time for the input pressure to
stabilize.
2. From the communicator main menu select 1 Device setup,
2 Diagnostics and service, 3 Calibration,3 Sensor trim, 2 Lower sensor trim to
prepare to adjust the lower trim point.
HART Fast Keys 1, 2, 3, 3, 1
HART Fast Keys 1, 2, 3, 3
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2-11
EN
NOTE
Select pressure input values so that the low and high values are equal to or outside
the 4 and 20 mA points. Do not attempt to obtain reverse output by reversing the
high and low points. The transmitter allows approximately a 5% URL deviation from
the characterized curve established at the factory.
3.Follow the commands provided by the communicator to complete the
adjustment of the lower value.
4.Repeat the procedure for the upper value, replacing 2 Lower sensor trim with
3 Upper sensor trim in Step 2.
Output Trim
The output trim commands allow you to alter the transmitter’s conversion of the
input signal to a 4–20 mA output (see Figure 2-3 on page 2-9). Adjust the analog
output signal at regular intervals to maintain measurement precision. Match the
transmitter output to the output of the digital readout device (ammeter, DCS, etc.).
You can trim the transmitter output using either the digital to analog trim or the
scaled digital to analog trim function.
Digital to Analog Trim
To perform a digital-to-analog trim, perform the following procedure.
1.From the HOME screen, select 1 Device setup, 2 Diag/Service, 3 Calibration, 4
D/A trim. Select “OK” to after you set the control loop to manual.
2.Connect an accurate reference meter to the transmitter at the “Connect
reference meter” prompt. To do so, connect the meter across the test terminals
in the transmitter terminal compartment, or use the readoutdevice within the
loop.
3.Select “OK” after connecting the reference meter.
4.Select “OK” at the “Setting fld dev output to 4 mA” prompt.
The transmitter outputs 4.00 mA.
5.Record the actual value from the reference meter, and enter it at the “Enter
meter value” prompt.
The communicator prompts you to verify whether or not the output value equals the
value on the reference meter.
6.Select 1 Yes if the reference meter value equals the transmitter output value,
or 2 No if it does not.
If you select 1 Yes, proceed to Step 7.
If you select 2 No, repeat Step 5.
HART Comm. 1, 2, 3, 2, 1
1
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2-12
EN 7.Select “OK” at the “Setting fld dev output to 20 mA” prompt, and repeat Steps
5 and 6 until the reference meter value equals the transmitter output value.
Select “OK” after you return the control loop to automatic control.
Scaled Digital to Analog Trim
The Scaled D/A Trim command matches the 4 and 20 mA points to a user-selectable
reference scale other than 4 and 20 mA (1 to 5 volts if measuring across a 250 ohm
load, or 0 to 100 percent if measuring from a DCS, for example). To perform a scaled
D/A trim, connect an accurate reference meter to the transmitter and trim the
output signal to scale as outlined in the Output Trim procedure.
NOTE
Use a precision resistor for optimum accuracy. If you add a resistor to the loop,
ensure that the power supply is sufficient to power the transmitter to a 20 mA
output with the additional loop resistance.
DIAGNOSTICS AND SERVICE
Test Device
The Test device command initiates a more extensive diagnostic routine than that
performed continuously by the transmitter. If the transmitter test detects a problem,
the communicator displays messages to indicate the source of the problem.
Loop Test
The Loop Test command verifies the output of the transmitter, the integrity of the
loop, and the operations of any recorders or similar devices installed in the loop. To
initiate a loop test, perform the following procedure:
1.From the HOME screen, Select 1 Device Setup, 2 Diagnostics and Service, 2
Loop Test, to prepare to perform a loop test.
2.Select “OK” after you set the control loop to manual.
The communicator displays the loop test menu.
3.Select a discreet milliamp level for the transmitter to output. At the “Choose
analog output” prompt, select 1 4mA, 2 20mA, or select 3 other to manually
input a value between 4 and 20 milliamps.
HART Comm. 1, 2, 3, 2, 2
HART Fast Keys 1,2,1,1
HART Fast Keys 1, 2, 2
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