Alcatel Vacuum Technology BARATRON 623A User manual

Alcatel Vacuum Technology France
98, avenue de Brogny BP 2069
74009 ANNECY Cedex
Tel : [phone]
Fax : [phone]
Telex : 385 153 F
pt.BTrippt.ATrip Ad jAdj
Zero
TYPE 624
1
8
15
TB2
TB1
r
essure Transducer With Tr ip Points
<RG< <RG<
P
BARATRON®
TYPES 623A/624A/625A
ABSOLUTE PRESSURE TRANSDUCERS
Date : 09.1998
EDITION 02
Instruction manual P/N 105460

ii 105460 - Ed 02
For more information or literature, contact:
Alcatel Vacuum Technology France
98 av. de Brogny
74009 ANNECY Cedex France
Phone: [phone]
FAX: [phone]
Copyright © 1996 by MKS, Inc. for Alcatel High Vacuum Technology
All rights reserved. No part of this work may be reproduced or transmitted in any form or by any
means, electronic or mechanical, including photocopying and recording, or by any information
storage or retrieval system, except as may be expressly permitted in writing by Alcatel.
Swagelok®, VCR®, and VCO®are registered trademarks of Swagelok Marketing Co., Solon, OH
Baratron®is a registered trademark of MKS Instruments, Inc., Andover, MA
Inconel® is a registered trademark of Inco Alloys International, Huntington, WV

Table of Contents
105460 - Ed 02 iii
Table of Contents
■Safety Procedures and Precautions.............................................................1
■Chapter One: General Information...........................................................3
■Introduction................................................................................................................. 3
■How This Manual is Organized .................................................................................... 4
■Customer Support ....................................................................................................... 4
■Chapter Two: Installation .........................................................................5
■How To Unpack The Transducer .................................................................................. 5
•Unpacking Checklist ................................................................................................ 5
■Alcatel Companion Products ........................................................................................ 6
■Fittings........................................................................................................................8
■Setup .......................................................................................................................... 9
•Dimensions ........................................................................................................... 10
•Electrical Installation .............................................................................................. 10
•Interface Cables .................................................................................................... 12
•Checking the Transducer Zero................................................................................ 13
■Chapter Three: Overview .......................................................................15
■General .................................................................................................................... 15
■Sensor ...................................................................................................................... 15
■Signal Conditioner/Electronics.................................................................................... 16
■The Endcap............................................................................................................... 16
■Chapter Four: Operation .......................................................................17
■General .................................................................................................................... 17
•Lowest Suggested Pressure Available for Reading .................................................... 17
•Lowest Suggested Pressure to Use for Control ......................................................... 17
■How To Set the Trip Points ......................................................................................... 19
■How To Adjust the Trip Point Direction ........................................................................ 21
■How To Adjust the Trip Point Hysteresis....................................................................... 25
■Chapter Five: Maintenance and Troubleshooting .....................................29
■General .................................................................................................................... 29
■Zero Adjustment........................................................................................................ 29
■Troubleshooting Chart............................................................................................... 31
■Appendix A: Product Specifications .........................................................33
■ALCATEL Type 623A.................................................................................................. 33
■ALCATEL Type 624A.................................................................................................. 34
■ALCATEL Type 625A.................................................................................................. 35
■Appendix B: CE Declaration of Conformity ...............................................37

List of Figures List of Tables
iv 105460 - Ed 02
List of Figures
Figure 1: Two Types of Installation .................................................................................6
Figure 2: Metal Single and Double Ferrule Compression-type Vacuum Fittings..................9
Figure 3: Baratron ® Capacitive Transducer’s Position ....................................................9
Figure 4: Dimensions of the Types 623A, 624A, and 625A Transducers .........................10
Figure 5: Power, Signal, and Chassis Grounding Scheme ..............................................11
Figure 6: The Endcap ..................................................................................................16
Figure 7: Analog Output versus Pressure ......................................................................18
Figure 8: How To Measure the Trip Point Voltage ..........................................................19
Figure 9: Placement of the Trip Point Adjustment Screws ................................................20
Figure 10: The Relay Board..........................................................................................22
Figure 11: The Alternate Relay Board............................................................................23
Figure 12: How Hysteresis Effects Accuracy and Relay Chatter........................................27
Figure 13: Location of the Zero Pot...............................................................................30
List of Tables
Table 1: Baratron® and Power supply Readouts compatibility ...........................................7
Table 2: Cable References ...........................................................................................10
Table 3: Required Inputs for the Types 623A, 624A, and 625A Transducers ...................11
Table 4: Terminal Block 1 (TB1) Pinout .........................................................................12
Table 5: Terminal Block 2 (TB2) Pinout .........................................................................13
Table 6: Suggested Pressures for Reading and Control ..................................................17
Table 7: Factory-Set Positions of the Shorting Jumpers...................................................24
Table 8: Shorting Jumper Positions for Hysteresis ..........................................................25
Table 9: Highest Pressure Suggested for Proper Zero Adjustment ...................................30
Table 10: Troubleshooting Chart..................................................................................31

Safety Procedures and Precautions
105460 - Ed 02 1
Safety Procedures and Precautions
ALLOW THE UNIT TO WARM UP
If the unit is used to control hazardous gases, they should not be applied before the unit
has completely warmed up.
USE THE PROPER SIGNAL/POWER CABLE
Use only the cable specified for your product. Use only a cable in good condition.
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 Alcatel Calibration and Service Center for service and repair to
ensure that all safety features are maintained.
SERVICE BY QUALIFIED PERSONNEL ONLY
Operating personnel must not remove instrument covers. Component replacement and
internal adjustments must be made by qualified service personnel only.
PURGE THE INSTRUMENT
After installing the unit, or before its removal from a system, be sure to purge the unit
completely with a clean dry gas to eliminate all traces of the previously used vapors.
DO NOT OPERATE IN EXPLOSIVE AMBIENT ATMOSPHERES
To avoid explosion, do not operate this product in an explosive atmosphere unless it has
been specifically certified for such operation.
USE PROPER FITTINGS AND TIGHTENING PROCEDURES
All instrument fittings must be consistent with instrument specifications, and compatible with
the intended use of the instrument. Assemble and tighten fittings according to
manufacturer’s directions.
CHECK FOR LEAK-TIGHT FITTINGS
Before proceeding to instrument set up, carefully check all plumbing connections to the
instrument to ensure leak-tight installation.
KEEP THE UNIT FREE OF CONTAMINANTS
Do not allow contaminants of any kind to enter the unit before or during use.
Contamination such as dust, dirt, lint, glass chips, and metal chips may permanently
damage the unit and nullify the warranty.
OPERATE AT PROPER PRESSURE
This transducer is designed for use in vacuum applications. It should not be used in
applications where the system may be exposed to greater than 45 psia or 120% of F.S.
(whichever is greater).
If an Ultra-Torr fitting is used, the system pressure should not exceed 1200 Torr absolute
pressure.

Safety Procedures and Precautions
2 105460 - Ed 02
Definitions of WARNING, CAUTION, and NOTE messages used throughout the manual.
Warning
The WARNING sign denotes a hazard. It calls attention to
a procedure, practice, condition, or the like, which, if not
correctly performed or adhered to, could result in injury to
personnel.
Caution
The CAUTION sign denotes a hazard. It calls attention to
an operating procedure, practice, or the like, which, if not
correctly performed or adhered to, could result in damage
to or destruction of all or part of the product.
Note
The NOTE sign denotes important information. It calls attention to a
procedure, practice, condition, or the like, which is essential to
highlight.

Chapter One: General Information Introduction
105460 - Ed 02 3
Chapter One: General Information
Introduction
The Baratron ® Type 623A 624A, and 625A Absolute Pressure Transducers are part of an
Alcatel family of general purpose pressure transducers designed to provide accurate,
reliable, and repeatable pressure measurements in the range from 1000 Torr down to 10
Torr full scale (F.S.). These instruments operate with ±15 VDC (±5%) input @ 75 mA,
400 mA, or 600 mA, depending upon the unit, and provide 0 to 10 VDC output linear with
pressure. All instruments expose only Inconel® to the process permitting use with corrosive
or dirty gases and eliminating contamination of the process with transducer materials.
Measurements are independent of gas composition and all of the units have a minimum
measuring range of four decades.
Using the latest single-sided, dual-electrode Inconel® transducer design, coupled with a
low impedance, fixed-frequency bridge signal conditioner, these instruments are capable of
withstanding high overpressure conditions (45 psia) with minimal or no shifts in output over
their range. The advanced bridge signal conditioning technology provides high accuracy
and is extremely stable during operation.
Protection from RF interference and noisy electrical environments is increased by the use of
a metal case, by internal design elements, and by the use of surge and ESD suppression
networks and RFI filtering on all inputs and outputs.
The Types 623A and 625A transducers have an accuracy of 0.25% of reading (optional
0.15% of reading with Type 623A), and the 624A unit has an accuracy of 0.12% of
reading. These instruments have been developed for applications requiring a small,
economical transducer which delivers accurate and repeatable measurements with a
resolution of 1 x 10
-4
F.S.
These transducers are designed specifically to meet the needs of vacuum process systems
where environmental and process conditions are particularly demanding. Temperature
control of the transducer minimizes the effects of ambient or process temperature variations
typically encountered in process line environments. The Type 623A is a general purpose
unheated unit, while the Type 624A controls the transducer temperature at 45° C, and the
Type 625A controls at 100° C, thereby minimizing contamination from the process and
affording better performance with ambient temperature variations.
All three transducers feature two trip point relays, each separately adjustable from 0.1 to
100% of Full Scale. The dimensions of the instruments are identical, and each transducer
has both a 5-pin (TB1) and 8-pin (TB2) terminal block on its cover.

How This Manual is Organized Chapter One: General Information
4 105460 - Ed 02
How This Manual is Organized
This manual is designed to provide instructions on how to set up and install a Type 623A,
624A, or 625A unit.
Before installing your Type 623A, 624A, or 625A unit in a system and/or
operating it, carefully read and familiarize yourself with all precautionary
notes in the
Safety Procedures and Precautions section at the front of this
manual. In addition, observe and obey all
WARNING and CAUTION notes
provided throughout the manual.
Chapter One: General Information, (this chapter) introduces the product and describes the
organization of the manual.
Chapter Two: Installation, explains the environmental requirements and describes how to
mount the instrument in your system.
Chapter Three: Overview, gives a brief description of the instrument and its functionality.
Chapter Four: Operation, describes how to use the instrument and explains all the
functions and features.
Chapter Five: Maintenance and Troubleshooting, describes maintenance and
troubleshooting procedures.
Appendix A: Product Specifications, lists the specifications of the instrument.
Appendix B : Declaration of conformity
Customer Support
Should any difficulties arise in the use of your Type 623A, 624A, and 625A instrument, or
to obtain information about companion products ALCATEL offers, contact any authorized
Alcatel Service Center. If it is necessary to return the instrument to ALCATEL, please contact
an Alcatel Service Center before shipping.
Please refer to the end of this manual for a list of Alcatel Service Centers.
Warning
All returns to Alcatel must be free of harmful, corrosive,
radioactive, or toxic materials.

Chapter Two: Installation How To Unpack The Transducer
105460 - Ed 02 5
Chapter Two: Installation
How To Unpack The Transducer
Alcatel has carefully packed the Absolute Pressure Transducer (Type 623A, 624A, and
625A) so that it will reach you in perfect operating order. Upon receiving the unit, however,
you should check for defects, cracks, broken connectors, etc., to be certain that damage
has not occurred during shipment.
Note
Do not discard any packing materials until you have completed your
inspection and are sure the unit arrived safely.
If you find any damage, notify your carrier and Alcatel immediately. If it is necessary to
return the unit to Alcatel, call the Alcatel Service Center before shipping. Please refer to the
end of this manual for a list of Alcatel Service Centers.
Unpacking Checklist
Standard Equipment
•The Type 623A, 624A, or 625A Absolute Pressure Transducer (specified at time of order)
•Two mating connectors - one for the 5-pin terminal block and one for the 8-pin terminal
block
•The Type 623A, 624A, and 625A Instruction Manual (this book)

Alcatel Companion Products Chapter Two: Installation
6 105460 - Ed 02
Alcatel Companion Products
The Baratron 623A - 624A - 625A can be installed & operated the following
ways :
POWER SUPPLY
A
ND DIGITAL
READOUT
(
PDR
)
BARATRON
CAPACITIVE
TRANSDUCER
VACUUM
FITTING
See
p
ara
g
ra
p
h:
"Electrical Installation"
p
a
g
e 11
See
p
ara
g
ra
p
h:
"Setu
p
"
p
a
g
e 9
See
p
ara
g
ra
p
h:
"Fittin
g
s"
p
a
g
e 8
VACUUM
CHAMBER
INSTALLATION WITH A POWER
DISPLAY AND READOUT
(
PDR
)
POWER SUPPLY
VACUUM
CHAMBER
SIGNAL
OUTPUT
CUSTOMER SPECIFIC
INSTALLATION
Figure 1: Two Types of Installation
The Type 623A, 624A, and 625A are compatible with:
•PDR-C-1C, PDR-C-2C, PDR 660B, PR 4000 readouts
Appropriate cables,see ‘Table 2: Cable References’ on page 10.

Chapter Two: Installation Alcatel Companion Products
105460 - Ed 02 7
Compatibility table of Baratrons® and Power Display Readouts:
PDRC-1C PDRC-2C PDR 660B PR 4000
623A zz z z
624A zz {z
625A zz {z
Table 1: Baratron® and Power supply Readouts compatibility
Legend
zPower Supply and Display
{The corresponding PDR can display the pressure information supplied by the gauge,
however as the power requirement of the gauge exceeds the PDR capacity, an external
power supply is necessary.
See Product Location and Requirements on page 8 for external power supply specifications.

Product Location and Requirements Chapter Two: Installation
8 105460 - Ed 02
Product Location and Requirements
Type 623A Absolute Pressure Transducer:
•Ambient operating temperature should remain between 0° C and 50° C
•Input required is ±15 VDC (±5%) @ 75 mA (maximum) with <20 mV p-p noise
and ripple
•Sensor operating temperature: ambient
Type 624A Absolute Pressure Transducer (Heated):
•Ambient operating temperature should remain between 15° C and 40° C
•Input required is ±15 VDC (±5%) @ 400 mA (maximum) with <20 mV p-p noise
and ripple
•Sensor operating temperature: temperature controlled @ 45° C
Type 625A Absolute Pressure Transducer (High Temperature):
•Ambient operating temperature should remain between 20° C and 50° C
•Input required is ±15 VDC (±5%) @ 600 mA (maximum) with <20 mV p-p noise
and ripple
•Sensor operating temperature: temperature controlled @ 100° C
For additional product requirements refer to Appendix A: Product Specifications, beginning
on page 33.
Fittings
The transducer port will easily carry the weight of the transducer. The following is a list of
available fittings.
•½’’ diameter (12.7 mm) tubulation
•DN 16 ISO-KF
•Swagelok
®
VCR
®
(female)
•Swagelok 8 VCO
®
(female)
•Mini-CF
Caution
Alcatel does not warranty the Type 623A, 624A, or 625A
transducer when single or double metal ferrule
compression-type vacuum fittings (shown on the following
page) are used because damage will occur to the
transducer when improper tightening procedures are
followed.

Chapter Two: Installation Setup
105460 - Ed 02 9
Single Ferrule Double Ferrule
Figure 2: Metal Single and Double Ferrule Compression-type Vacuum Fittings
Setup
▼
A L C
▲
T E L
▼
Manufactured by MKS Instruments, Inc.
Connector Side
Flange Side
Figure 3: Baratron ® Capacitive Transducer’s Position
Mount the transducer in the recommended orientation, that is, with the inlet port pointing
(vertically) downward. Although you can mount the unit in any orientation, mounting it as
suggested means that any foreign matter entering the pressure port will fall away from the
diaphragm.
Isolate the unit from vibration as much as possible. When not subject to gas damping at
low pressure, the diaphragm may become susceptible to resonance.

Setup Chapter Two: Installation
10 105460 - Ed 02
Dimensions
▼
A L C
▲
T E L
▼
(76.2)
3.00 DIA
(95.50)
(33.02)
(12.70)
0.500 DIA
3.76
1.30
0.31
(7.9)
(136.4)
5.37
Manufactured by MKS Instruments, Inc.
Figure 4: Dimensions of the Types 623A, 624A, and 625A Transducers
Electrical Installation
1- Installation with an PDR, Power Display Readout
Compatible cable
PDR-C-1C PDR-C-2C PDR 660 B PR 4000
623A ZC 473S3 ZC 473S3 ZC112S3 ZC112S3
624A ZC 473S3 ZC 473S3 ZC112S3 ZC112S3
625A ZC 473S3 ZC 473S3 Consult us ZC112S3
Table 2: Cable References
The cables described above are 3 m long shielded cables:
•To order 6 or 9 m cables : ZCxxxS6 (6 m shielded cables)
ZCxxxS9 (9 m shielded cables)
•For other lenghts, consult Alcatel.

Chapter Two: Installation Setup
105460 - Ed 02 11
2- Customer Specific Installation
The Types 623A, 624A, and 625A transducers each require an external power source
capable of supplying the voltages stated in Table 3, shown on page 11. Noise and ripple
should be less than 20 mV p-p.
Any readout device that has input capabilities of less than 0 to greater than 10 VDC and
impedance greater than 10k ohms can be used.
Note
The ground of any external power supply and readout should be the
same as the transducer ground (chassis ground) to minimize any
possible ground loops that can affect the performance and stability
of the system.
Required Inputs for the Types 623A, 624A, and 625A Transducers
Input Required Type 623A Type 624A Type 625A
At Startup ±15 VDC (±5%) @
75mA
±15 VDC (±5%) @
400mA
±15 VDC (±5%) @
600mA
After 1 hour of
operation at 25°C
±15 VDC (±5%) @
75mA
±15 VDC (±5%) @
300mA
±15 VDC (±5%) @
500mA
Table 3: Required Inputs for the Types 623A, 624A, and 625A Transducers
Readout
Power
Supply
+
-
0 - 10V Pressure Output
Signal Common
+ 15V
- 15V
Power Common
+ 15V 10K 1 F
Chassis
Ground
Sensor
Port
The absolute value of the potential difference between
the chassis ground and signal common/power ground
should not exceed 14 volts.
NOTE: For best results, use a readout with fully
differential inputs.
Multiple Ground
Tie-Point
Figure 5: Power, Signal, and Chassis Grounding Scheme

Setup Chapter Two: Installation
12 105460 - Ed 02
Interface Cables
Refer to electrical installation paragraph page 10.
For cables that will be connected to non-Alcatel products, Alcatel can provide normal
shielded or braided shielded cable assemblies in a nominal 10’ (3m) length, terminating in
flying leads (pigtail) fashion at both ends. Alcatel recommends braided shielded cable
assemblies if the environment contains high EMI/RFI noise.
The pinouts of the two terminal blocks on the Types 623A, 624A, and 625A transducers are
listed on each endcap and in Table 4 (shown below) and Table 5 (page 13).
Terminal Block 1 (TB1) Pinout
Pin Signal
1 Power Common
2 Signal Common
3 Signal Output
4 - 15 VDC
5 + 15 VDC
Chassis Ground is made by using the screw labeled CHASSIS
Table 4: Terminal Block 1 (TB1) Pinout

Chapter Two: Installation Setup
105460 - Ed 02 13
Terminal Block 2 (TB2) Pinout
Pin Signal
1Trip Point A level (0 to 10 Volts)*
2Trip Point A relay, Normally Closed
3Trip Point A relay, Common
4Trip Point A relay, Normally Open
5Trip Point B relay, Normally Open
6Trip Point B relay, Common
7Trip Point B relay, Normally Closed
8Trip Point B level (0 to 10 Volts)*
* use pin 2 of TB1 for trip point signal common
Table 5: Terminal Block 2 (TB2) Pinout
Checking the Transducer Zero
For initial operation, and periodically as required, check the transducer zero. Set (or re-set)
the zero by adjusting the zero potentiometer located on the top cover or at the front panel
of any Power Supply/Readout you are using. It is important that you make the zero
adjustment only after the unit is fully stabilized. Stabilization is accomplished by pumping
the unit, with the power on, to a pressure less than the transducer resolution (0.01% of full
scale) for approximately:
•15 minutes for the Type 623A transducer
•2 - 4 hours for both the Type 624A and Type 625A transducers
Note
Once the unit is properly warmed up and stabilized, make the zero
adjustment at a pressure less than the transducer’s resolution
(0.01% of F.S.).

14 105460 - Ed 02
This page intentionally left blank

Chapter Three: Overview General
105460 - Ed 02 15
Chapter Three: Overview
General
A pressure transducer includes a sensor and signal conditioner. It needs a low voltage
power supply to operate (see Chapter 2 - Installation)
The pressure transducers converts the pressure information to an analog linear output.
This information can be displayed on a PDR (Power Supply and Digital Readout), refer to
Chapter 2.
Sensor
The variable capacitance sensor
consists of a pressure inlet tube (port)
connected to a small chamber in the
transducer body. One wall of this
chamber is an elastic metal
diaphragm. The front side of the
diaphragm is exposed to the gas
whose pressure is to be measured.
The back, or reference side of the
diaphragm faces a rigidly mounted
ceramic disc containing two
electrodes. The reference side is
permanently evacuated (10
-7
Torr)
and its vacuum is maintained with a
chemical getter system.
The diaphragm deflects with changing
absolute pressure (force per unit area)
independently of the gas type or
composition of the measured gas.
This deflection causes an imbalance
of the sensor electrode capacitances since the distance to the diaphragm is now different
for each electrode. The imbalance of capacitances is converted to a DC voltage in the
bridge. This bridge is excited by a precision constant frequency oscillator. The resultant
signal is then linearized, zeroed, and amplified via the signal conditioner electronics, to
produce a precise 0 to 10 VDC signal scaled to the range of the transducer.
In the heated models (Types 624A and 625A), zero and span stability is further increased
because the sensor and bridge electronics are temperature controlled. This thermal
enclosure reduces the effects of ambient temperature changes by a factor of at least 35
(that is a 35° C change in ambient temperature will produce less than a 1° C change inside
the thermal housing).

Signal Conditioner/Electronics Chapter Three: Overview
16 105460 - Ed 02
Signal Conditioner/Electronics
The signal conditioner contains a state-of-the-art, low impedance balanced bridge circuitry,
self-compensated for thermal stability with ambient temperature changes. Output is a DC
voltage which is linear with pressure. The transducer is then calibrated against a pressure
standard to provide a 0 to 10 volt DC output over the range of the transducer.
The Endcap
Shown below is the endcap of a Type 624A transducer. The endcaps of the Types 623A
and 625A instruments are functionally the same.
pt.BTrippt.ATrip Adj
Adj
Zero
TYPE 624
18
15
TB2
TB1
Pressure Transducer
<RG< <RG<
indicates pressure is below the trip point
indicates pressure is above the trip point
Green:
Red:
Alarm Trip Point Indicator LEDs
For Trip Point A For Trip Point B
Adjustment screw
for Trip Point A
Adjustment screw
for Trip Point B
Zero Pot.
Figure 6: The Endcap
The endcap provides easy access for zero adjustment, electrical connections to terminal
blocks TB1 and TB2, and trip point adjustment screws. The LEDs indicate when the
transducer is powered (they light) and the status of the pressure relative to each of the trip
points. A green LED indicates the pressure is below the alarm trip point, and a red LED
indicates the pressure is above the alarm trip point.