Kurt J. Lesker 100014434 User manual

Operation and
Maintenance Manual
Series 902
Piezo Transducer

Series 902 Piezo
Part # 100014434
Series 902
Piezo Transducer

Series 902 Piezo
Part # K___________
Please fill in the transducer part and flange type numbers
in the space above and have them readily available when
calling for service or additional information.
(The part number can be found on your packing slip. Both
the part number and serial number are located on the
bottom side of the housing.)
For more information or literature, contact:
Kurt J. Lesker Company
1925 Worthington Avenue
Clairton, PA 15025 USA
Phone: [phone]
1-800-245-1656
Fax: [phone]
©2002 by the Kurt J. Lesker Company, All rights reserved.

Series 902 Piezo
Table of Contents
Package Contents ..................................................................... 7
Symbols Used in this Manual .................................................... 8
Safety Precautions .................................................................... 9
General Specifications ............................................................ 10
Feature and Control Locations ................................................ 11
902 Piezo ...............................................................................................11
Optional Piezo Display Module ..............................................................11
About the 902 Piezo ................................................................ 12
Typical Applications for the 902 Piezo ..................................... 13
Installing the 902 Piezo ........................................................... 14
Transducer Installation ............................................................................14
Location ...........................................................................................14
Orientation .......................................................................................14
Contamination ..................................................................................14
Vacuum Connection ...............................................................................14
Electrical Connection .............................................................................15
Input/Output Wiring ..........................................................................15
902 Piezo Electrical Connections Table ...........................................16
Relay Inductive Loads and Arc Suppression ..........................................16
Piezo Display Module Connection .......................................................... 17
Operation................................................................................. 18
902 Piezo Factory Defaults Table ...........................................................18
RS-485 Protocol .....................................................................................19
Standard Addresses ........................................................................19
Universal Addresses ........................................................................19
Query and Command Syntax ...........................................................19
Response Syntax (ACK/NAK) .........................................................20
RS-485 Command Set ............................................................ 21
Set Up Commands ................................................................................. 21
Address – AD ..................................................................................21
Analog Output Format – DAC .......................................................... 21
Baud Rate – BR ...............................................................................21
Factory Default – FD ........................................................................22
Unit – U ............................................................................................22
User Tag – UT ..................................................................................22
Status Commands..................................................................................22
Device Type – DT .............................................................................22
Firmware Version – FV .....................................................................22
Hardware Version – HV ....................................................................23

Series 902 Piezo
Manufacturer – MF...........................................................................23
Model – MD .....................................................................................23
Pressure Reading – PR1 ..................................................................23
Serial Number – SN ......................................................................... 23
Time On – TIM ................................................................................. 23
Transducer Temperature – TEM ........................................................23
Set Point Commands .............................................................................24
Set Point Value – SP1 ...................................................................... 24
Hysteresis Value – SH1 ...................................................................24
Set Point Direction – SD1 ................................................................ 24
Enable Set Point – EN1 ................................................................... 25
Set Point Status – SS1 .................................................................... 25
Calibration Commands ........................................................................... 25
User Zero Calibration – ZER ............................................................ 25
User Span Calibration – SPN ...........................................................25
Analog Output ......................................................................... 26
Linear versus Logarithmic Analog Output ...............................................26
Linear Analog Output .......................................................................26
Logarithmic Analog Output .............................................................. 26
Linear 10 .......................................................................................... 27
Linear 5 ............................................................................................ 28
Logarithmic 10 .................................................................................29
Logarithmic 5 ...................................................................................30
Pressure to Voltage Table.................................................................31
Maintenance and Troubleshooting .......................................... 32
Maintenance and Troubleshooting Table ..................................................32
Accessories and Part Replacement ........................................ 33
Warranty .................................................................................. 34
Appendix: How the 902 Piezo Transducer Works .................... 35

Series 902 Piezo 7
Before unpacking the 902 Piezo Transducer, check all surfaces of the packing
material for shipping damage.
Confirm that the 902 Piezo package contains these items:
♦1 902 Piezo Transducer
♦1 902 Piezo Transducer Operation and Maintenance Manual
Inspect the components for visible evidence of damage during shipment. If
anything has been damaged, notify the carrier immediately. Keep all shipping
materials and packaging for claim verification.
If any items are missing from the package, call Kurt J. Lesker
Customer Service at 1-412-387-9200 or 1-800-245-1656.
Do not return the product to Kurt J. Lesker unless specified to do so by Kurt J.
Lesker Customer Service.
Kurt J. Lesker Company Telephone [phone]
5330 Sterling Dr. Toll-Free 1-800-245-1656 (USA only)
Boulder, CO 80301 Facsimile 1-412-384-2745
USA
Package Contents

8 Series 902 Piezo
CAUTION: Refer to the manual. Failure to heed the message could
result in personal injury, serious damage to the equipment, or both.
Calls attention to important procedures, practices, or
conditions.
Symbols Used in this Manual

Series 902 Piezo 9
Safety Precautions
Do not substitute parts or modify instrument. Do not install
substitute parts or perform any unauthorized modification to the
instrument. Return the instrument to an Kurt J. Lesker Calibration and
Service Center for service and repair to ensure that all of the safety
features are maintained.
Properly ground the transducer. The transducer should be
connected to earth ground both through the vacuum flange and the
back shell of the electrical connector.
Allow only qualified technicians to service the 902 Piezo
transducer. Users should not remove covers, casing, or plug-in
components. Injury may result. A qualified technician must perform
any part replacement or internal adjustments.
Keep the unit free of contaminants. Do not allow contamination of
any kind to enter the unit before or during use. Contaminants such
as dust, dirt, lint, glass chips, and metal chips may permanently
damage the unit.

10 Series 902 Piezo
General Specifications
0.1 to 1000 Torr
1 to 1000 Torr
0 to 5 VDC
0 to 10 VDC
2000 Torr
1.0% Reading
± 0.03% FS
± 0.02% FS/ oC
± 0.02% FS/ oC
50 Milliseconds
12 to 30 VDC
0.5 Watts
1A @ 30 VAC/VDC
304 stainless steel, 316 stainless steel
Stainless steel, aluminum
0.21 in3(3.4 cm3)
0 to 50 oC
85oC
Any
EMC Directive 89/336/EEC
NW16 KF, 4 VCR®F, 8 VCR®F
1.5” x 1.5” x 2.25” (38.1 x 38.1 x 57.2 mm)
3.4 oz. (97 g)
Measuring range
Set point range
Analog out
Maximum pressure
Accuracy
Repeatability
Temperature effect on span
Temperature effect on zero
Response time
Supply voltage
Power consumption
Relay contact rating
Materials exposed to
vacuum
Housing material
Internal volume (with KF 16)
Operating temperature
Bakeout temperature (off)
Installation orientation
CE Certification
Vacuum connections
Dimensions (with KF 16)
Weight (with KF 16)

Series 902 Piezo 11
902 Piezo
User access is through the 9-pin D-sub connector.The ZERO adjust button
allows the user to manually perform a zero calibration.The user can perform
zero calibration whenever the pressure is below 10 mTorr. See Calibration
Commands in the RS-485 Command Set section for more information.
The figure below shows the top view of the 902.
Optional Piezo Display Module
The 902 has an optional Piezo Display Module (PDM) to display pressure.
The display reads the analog output voltage from the 902 and translates the
data into pressure. To use the display module, the analog output format must
be set to LINEAR10 (see Analog Output Format – DAC in the Set Up
Commands section). The display has a resolution of 3½ digits, and shows
three decades of pressure.
The figure below shows the optional PDM.
TORR
Feature and Control Locations
ZERO
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12 Series 902 Piezo
The 902 Piezo measures chamber pressures directly as a force or pressure is
applied to the 902 Piezo’s diaphragm. Once integrated into the vacuum
system, the 902 Piezo’s functions are computer-controlled, requiring little
manual intervention by the user. This enables the system to monitor pressure
as a procedure invisible to the user, and when the desired pressure is
reached, trigger the next event in the system process.
This manual describes the installation and configuration tasks necessary to
set up the 902 Piezo. After the device is set up, a software engineer at the
user’s installation would use the communications protocol described in this
manual to create a software program (in, for example, Visual Basic, C, or
C++) that will automatically control 902 Piezo operation.
For additional information on how the 902 Piezo works, see the appendix How
the 902 Piezo Works.
About the 902 Piezo

Series 902 Piezo 13
Typical Applications for the 902
Piezo
♦Atmospheric and sub-atmospheric pressure sensing.
♦Measure fore and roughing pressures generated by mechanical vacuum
pumps.
♦Alarms to warn of abnormal pressures.
♦Start or stop system processes with a relay set point.
♦Monitor backfill and venting of gases.
♦Control system pressure using digital communications or an analog
output as an input to an automatic pressure controller.

14 Series 902 Piezo
Transducer Installation
Location
Locate the 902 where it can measure chamber or manifold pressure.
Orientation
The 902 can be mounted in any orientation without change of output or
calibration.
Contamination
Locate and orient the Piezo where contamination is least likely. For example,
if the 902 is mounted directly above a source of evaporation, the vapor could
contaminate the sensor elements and cause the calibration to shift. Whenever
possible, install the 902 with the vacuum port facing down to keep
particulates or liquids from entering the device.
Vacuum Connection
The 902 is available with the following flanges:
♦KF 16
♦4 VCR®F
♦8 VCR®F
The figure below shows the dimensions for each flange type.
Electrical Connection
Use a cable with a female 9-pin D-sub connector with strain reliefs to ensure
proper electrical connection and to reduce stress on the connectors.
Installing the 902 Piezo
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Series 902 Piezo 15
Ensure a low impedance electrical connection between the 902
sensor body and the grounded vacuum system to shield the
sensor from external electromagnetic sources.
Input/Output Wiring
The figure and the 902 Piezo Electrical Connections Table on the following
page identify the pins of the 902 connector and their functions; make a cable
using this information.To comply with EN61326-1 immunity requirements, use
a braided, shielded cable. Connect the braid to the metal hoods at both ends
of the cable with the end for power supply connected to earth ground.
The power supply input is 12 to 30 VDC.The positive side of the power supply
is connected to pin 3 and the negative side to pin 4 of the male D-sub
connector.
Damage may occur to the circuitry if excessive voltage is applied,
polarity reversed, or if a wrong connection is made.
If using analog output (described in the Analog Output section), the analog
output voltages are pins 5 (+) and 8 (-). Connect them to a differential input
voltmeter or an analog-to-digital (A/D) converter with a differential input in a
system controller.
Do not connect the negative side of the analog output (pin 8) to
the negative side of the power supply input (pin 4) or to any
other ground. Doing so will cause half of the power current to
flow through this wire. Measurement errors in the output
voltage may be seen due to the voltage drop from this current.
The longer the cable, the worse the error will be.
Do not connect the set point relay terminals to the analog output.
902 Piezo Electrical ConnectionsTable
The digital communications connections are pins 7 and 9. RS-485 uses pin 7
for RS485(-) and pin 9 for RS485(+). RS-232 uses pin 7 for RS232 transmit
(TXD) and pin 9 for RS232 receive (RXD).
Relay Inductive Loads and Arc Suppression
If using the set point relay to switch inductive loads (e.g., solenoids, relays,
transformers, etc.), the arcing of the relay contacts might interfere with 902
operation and reduce relay contact life.Therefore, an arc suppression
network, shown schematically below, is recommended.

16 Series 902 Piezo
The values of the capacitance C and the resistance R can be calculated by
the following equations:
C = I2/(1 x 107)
R = E/ Ia
where:
C is in farads
R is in ohms
I is DC or Acpeak load current in amperes
E is DC or Acpeak source voltage in volts
a = 1 + (50/ E)
Note that Rmin = 0.5 Ωand Cmin = 1.0 x 10-9 F
PIN 1 PIN 5
PIN 6 PIN 9
MALE CONNECTOR
ON 902
RELAY N.O.
RELAY N.C.
POWER +
POWER -
ANALOG OUT +
RELAY COMMON
RS485 - / RS232 TXD
ANALOG OUT -
RS485 + / RS232 RXD

Series 902 Piezo 17
Piezo Display Module Connection
The Piezo Display Module (PDM) attaches to the 902 through the D-sub
connector. The PDM has a through connector to attach the combined PDM
and 902 unit to the rest of the system. The following figure shows how to
connect the PDM to the 902. Use the two slide lock posts supplied with the
PDM kit.
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18 Series 902 Piezo
Operation
The 902 Piezo operation parameters are preset at the factory. The table below
shows the factory default settings. Use the user interface and the commands
described on the following pages to change parameter settings as necessary.
The user interface to the 902 Piezo is through either RS-232 or RS-485 serial
communications. RS-232 and RS-485 use the same commands to
communicate with the 902; however, RS-485 allows communication with
multiple transducers, whereas RS-232 allows communication with only a
single transducer.The remainder of this manual refers to RS-485 only.
902 Piezo Factory Defaults Table
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Series 902 Piezo 19
RS-485 Protocol
The 902 supports 2400, 4800, 9600, and 19200 baud rates (factory
default: 9600). The data format is 8 data bits, no parity, and one stop bit.
Standard Addresses
Valid addresses are 1 to 253 (factory default: 253).
Universal Addresses
The 902 receives and responds to commands sent to address 254. For
example, use 254 to communicate with a device if its address is unknown.
The 902 receives and acts upon commands sent to address 255, but does
not respond; use 255 to broadcast messages to multiple devices attached to
the same system. For example, use 255 to change the analog output format
for all devices.
Query and Command Syntax
Queries return current parameter settings; commands change the parameter
setting according to the value the user types in the command syntax. Each
query or command must begin with the attention character @ and end with
the termination string ;FF.
Syntax required for a query is:
@<device address><query>?;FF.
Syntax required for a command is:
@<device address><command>!<parameter>;FF.
Examples:
Query current baud rate: @253BR?;FF
Change baud rate to 19200: @253BR!19200;FF
where:
@ <attention character>
253 <device address>
BR? <query> (for query syntax)
BR!19200 <command>!<parameter> (for command syntax)
;FF <terminator>

20 Series 902 Piezo
Response Syntax (ACK/NAK)
The ASCII characters 'ACK' or 'NAK' preface the query or command response
string. The ACK sequence signifies the message was processed
successfully. The NAK sequence indicates there was an error.
The response to a query or a successful command is:
@<device address>ACK<data>;FF
The response to a message with an error is:
@<device address>NAK<NAK code>;FF
Examples:
ACK response: @253ACK9600;FF (baud rate changed to 9600)
NAK response: @253NAK160;FF (command had an error—possibly
a typo)
The following list provides descriptions of the NAK codes that may be
returned.
Error NAK Code
Invalid zero calibration parameter 5
Invalid span calibration parameter 6
Invalid zero calibration reading 8
Invalid span calibration reading 9
Unrecognized message 160
Invalid argument 169
Value out of range 172
Command/query character invalid (! or ?) 175
Invalid decimal number 176
Write to Flash EE failed 196
Read from Flash EE failed 197