MKS 640A User manual

116669-P1
Rev B, 12/97
MKS Type 640A/641A
Pressure Controller

Copyright © 1997 by MKS Instruments, Inc.
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
MKS Instruments, Inc.
Baratron®is a registered trademark of MKS Instruments, Inc., Andover, MA
Cajon®is a registered trademark of Cajon Company, Macedonia, OH
Kalrez®and Viton®are registered trademarks of E. I. DuPont de Nemours and Co. Inc.,
Wilmington, DE
NUPRO®is a registered trademark of Crawford Fitting Company, Solon, OH
Swagelok®, VCR®, and VCO®are registered trademarks of Swagelok Marketing Co., Solon,
OH
Inconel®is a registered trademark of Inco Alloys International, Inc., Huntington, WV
Chemraz®is a registered trademark of Greene, Tweed, & Co., Inc., Kulpsville, PA

Kel-F®is a registered trademark of 3M Company, Minneapolis, MN

Table of Contents
v
Table of Contents
Pressure Transducer Safety Information..............................................................................1
Symbols Used in This Instruction Manual.................................................................1
Symbols Found on the Unit......................................................................................2
Safety Procedures and Precautions..........................................................................3
Chapter One: General Information......................................................................................5
Introduction............................................................................................................5
How This Manual is Organized................................................................................6
Manual Conventions ...................................................................................6
Customer Support...................................................................................................7
Chapter Two: Installation ...................................................................................................9
How To Unpack the 640 Series Controller ...............................................................9
Unpacking Checklist...................................................................................9
Product Location and Requirements.........................................................................10
Interface Cables.....................................................................................................11
Generic Shielded Cable Description .............................................................12
Dimensions ............................................................................................................13
Front and Back Views................................................................................13
Side View..................................................................................................14
Setup.....................................................................................................................15
Fittings.......................................................................................................15
Mounting Hardware....................................................................................15
Gas Pressure..............................................................................................15
Installing the Unit........................................................................................16
The I/O Connector .....................................................................................18
Initial Configuration.................................................................................................20
Chapter Three: Overview...................................................................................................21
General Information................................................................................................21
Pressure Control Range ..............................................................................21

Table of Contents
vi
A Typical Control System...........................................................................22
How The 640 Series Pressure Controller Works.......................................................23
Tuning the 640 Series Pressure Controller................................................................24
Proportional Term.......................................................................................24
Integral Term.............................................................................................25
Tuning the 640 Controller............................................................................27
Priority of Commands .............................................................................................29
Trip Points .............................................................................................................30
Action of the Trip Points.............................................................................30
Applications with a Large Differential Pressure........................................................31
Labels....................................................................................................................31
Chapter Four: Operation.....................................................................................................33
How To Check the Zero.........................................................................................33
How To Zero a Type 640 (Absolute) Unit....................................................33
How To Zero a Type 641 (Gage) Unit .........................................................34
How To Adjust the Span.........................................................................................35
How To Tune the 640 Series Controller ...................................................................35
How To Adjust the Trip Point Values ......................................................................36
How To Select the Trip Point Action .......................................................................37
How To Use Trip Points as Error Indicators.............................................................39
How To Change the Pressure Output Signal Range ..................................................40
How To Select Upstream Control............................................................................42
Appendix A: Product Specifications ....................................................................................45
Performance Specifications.....................................................................................45
Environmental Specifications ...................................................................................46
Trip Point Specifications..........................................................................................46
Physical Specifications............................................................................................47
Appendix B: Valve Orifice Selection...................................................................................49
General Information................................................................................................49
Checking the Orifice Size............................................................................49
How To Verify the Orifice Selection........................................................................51

Table of Contents
vii
Using Different Gases ................................................................................54
Appendix C: Gas Density Table ..........................................................................................57
Appendix D: Model Code Explanation.................................................................................61
Model Code Description..........................................................................................61
Index.................................................................................................................................65

Table of Contents
viii

List of Figures
ix
List of Figures
Figure 1: Front and Back Views of the 640 Series Controller................................................13
Figure 2: Side View of the 640 Series Controller..................................................................14
Figure 3: Bottom View of the 640 Series Controller..............................................................15
Figure 4: Downstream Pressure Control..............................................................................16
Figure 5: Upstream Pressure Control..................................................................................17
Figure 6: Top View of the 640 Series Controller...................................................................21
Figure 7: Sample Pressure Control System..........................................................................23
Figure 8: Effects of the Proportional Control........................................................................24
Figure 9: Effects of the Integral Control..............................................................................25
Figure 10: Controller Response with Initial P Term and I Term Values..................................27
Figure 11: Controller Response with Increased P Term........................................................28
Figure 12: Controller Response with Increased I Term.........................................................28
Figure 13: Serial Number Label..........................................................................................31
Figure 14: Jumper Positions on the Transducer Board..........................................................37
Figure 15: Jumper Positions on the Control Board................................................................42
Figure 16: Model Code Explanation.....................................................................................49
Figure 17: Flow Range Selection.........................................................................................53

List of Figures
x

List of Tables
xi
List of Tables
Table 1: Definition of Symbols Found on the Unit.....................................................................2
Table 2: Interface Cables..................................................................................................... 11
Table 3: Fitting Dimension.................................................................................................... 13
Table 4: I/O Connector Pinout.............................................................................................. 18
Table 5: Initial Configuration................................................................................................. 20
Table 6: Highest Pressure Suggested for Zero Adjustment of an Absolute Transducer............. 34
Table 7: Orifice Size ............................................................................................................ 50
Table 8: Valve Orifice Index Number ................................................................................... 52
Table 9: Pressure Range Selection........................................................................................ 62
Table 10: Fitting Type Selection............................................................................................ 62
Table 11: Valve Type........................................................................................................... 62
Table 12: Seal Material Selection.......................................................................................... 63
Table 13: Valve Orifice Size Selection................................................................................... 63
Table 14: Trip Point Model Code Entry................................................................................. 64
Table 15: Valve Plug Material.............................................................................................. 64

List of Tables
xii

Pressure Transducer Safety Information Symbols Used in This Instruction Manual
1
Pressure Transducer Safety Information
Symbols Used in This Instruction Manual
Definitions of WARNING, CAUTION, and NOTE messages used throughout the manual.
Warning The WARNING sign denotes a hazard to personnel. 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 to equipment. 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.

Symbols Found on the Unit Pressure Transducer Safety Information
2
Symbols Found on the Unit
The following table describes symbols that may be found on the unit.
Definition of Symbols Found on the Unit
|
On (Supply)
IEC 417, No.5007 Off (Supply)
IEC 417, No.5008 Earth (ground)
IEC 417, No.5017
Protective earth
(ground)
IEC 417, No.5019
Frame or chassis
IEC 417, No.5020 Equipotentiality IEC 417, No.5021 Direct current IEC 417, No.5031
Alternating current
IEC 417, No.5032
Both direct and
alternating current
IEC 417, No.5033-a
Class ll equipment
IEC 417, No.5172-a
Three phase
alternating current
IEC 617-2 No.020206
Caution, refer to
accompanying
documents
ISO 3864, No.B.3.1
Caution, risk of
electric shock
ISO 3864, No.B.3.6
Caution, hot surface
IEC 417, No.5041
Table 1: Definition of Symbols Found on the Unit

Pressure Transducer Safety Information Safety Procedures and Precautions
3
Safety Procedures and Precautions
Observe the following general safety precautions during all phases of operation of this
instrument. Failure to comply with these precautions or with specific warnings elsewhere in
this manual violates safety standards of intended use of the instrument and may impair the
protection provided by the equipment. MKS Instruments, Inc. assumes no liability for the
customer’s failure to comply with these requirements.
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 MKS 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 attempt component replacement and internal adjustments. Any
service must be made by qualified service personnel only.
USE CAUTION WHEN OPERATING WITH HAZARDOUS MATERIALS
If hazardous materials are used, users must take responsibility to observe the proper safety
precautions, completely purge the instrument when necessary, and ensure that the material used is
compatible with the materials in this product, including any sealing materials.
PURGE THE INSTRUMENT
After installing the unit, or before removing it from a system, purge the unit completely with a
clean, dry gas to eliminate all traces of the previously used flow material.
USE PROPER PROCEDURES WHEN PURGING
This instrument must be purged under a ventilation hood, and gloves must be worn for protection.
DO NOT OPERATE IN AN EXPLOSIVE ENVIRONMENT
To avoid explosion, do not operate this product in an explosive environment 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.

Safety Procedures and Precautions Pressure Transducer Safety Information
4
CHECK FOR LEAK-TIGHT FITTINGS
Carefully check all vacuum component connections to ensure leak-tight installation.
OPERATE AT SAFE INLET PRESSURES
Never operate at pressures higher than the rated maximum pressure (refer to the product
specifications for the maximum allowable pressure).
INSTALL A SUITABLE BURST DISC
When operating from a pressurized gas source, install a suitable burst disc in the vacuum system
to prevent system explosion should the system pressure rise.
KEEP THE UNIT FREE OF CONTAMINANTS
Do not allow contaminants to enter the unit before or during use. Contamination such as dust, dirt,
lint, glass chips, and metal chips may permanently damage the unit or contaminate the process.
ALLOW PROPER WARM UP TIME FOR TEMPERATURE-CONTROLLED UNITS
Temperature-controlled units will only meet specifications when sufficient time is allowed for the
unit to meet, and stabilize at, the designed operating temperature. Do not zero or calibrate the unit
until the warm up is complete.

Chapter One: General Information Introduction
5
Chapter One: General Information
Introduction
The 640A Series Pressure Controllers include the Type 640 absolute pressure controller and the
Type 641 gage pressure controller. The 640 Series Controllers consist of a Baratron®
capacitance manometer (either absolute or gage pressure), a normally closed proportional control
valve, and closed-loop control electronics. The closed-loop control circuitry enables the unit to
function as a proportional-integral (PI) controller. The unit’s compact size and small, three-inch
footprint reduce space requirements.
The 640 Series offers a variety of options including the seal material, full scale range, and
calibration. The seal material is available in an elastomer (Kalrez®, Viton®, Kel-F®, or
Chemraz®, refer to Appendix D: Model Code Explanation, page 61, for information) or all-
metal material. Full scale ranges are available from 10 Torr to 100 psi with a flow capacity of 50
sccm (standard cubic centimeters per minute) to 50 slm (standard liters per minute).
The 640 Series Pressure Controller can be used in either upstream or downstream pressure
control applications. The transducer inlet port is identified as the “Controlled Pressure Port” to
ensure that you install the 640 Pressure Controller into your system correctly.
The 640 Series Controllers provide two user-settable alarm trip points. The trip points can be set
from 1 to 100% of full scale. Each trip point controls an open collector transistor. An LED light
located on the top of the unit, indicates the trip point status.
Note The proportional control valve in the 640 Pressure Controller is not a
positive shutoff valve. Depending upon your application, you may need to
install a separate positive shutoff valve.

How This Manual is Organized Chapter One: General Information
6
How This Manual is Organized
This manual is designed to provide instructions on how to set up and install a 640 Series unit.
Before installing your 640 Series unit in a system and/or operating it, carefully read and
familiarize yourself with all precautionary notes in the Safety Messages and Procedures
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 controller with all its functions and features.
Appendix A: Product Specifications, lists the specifications of the instrument.
Appendix B: Valve Orifice Selection,presents the information used to select the appropriate
flow range for nitrogen and other gases.
Appendix C: Gas Density Table,lists the standard density of commonly used gases.
Appendix D: Model Code Explanation, explains how the model number of your 640 controller
lists the features included in the unit.
Manual Conventions
The following conventions apply throughout this manual:
XXXXXX For inputs: Indicates that the line must be pulled low to activate the function.
XXXXXX For outputs: Indicates that the output is active low.

Chapter One: General Information Customer Support
7
Customer Support
Standard maintenance and repair services are available at all of our regional MKS Calibration and
Service Centers listed on the back cover. In addition, MKS accepts the instruments of other
manufacturers for recalibration using the Primary and Transfer Standard calibration equipment
located at all of our regional service centers. Should any difficulties arise in the use of your 640
Series instrument, or to obtain information about companion products MKS offers, contact any
authorized MKS Calibration and Service Center. If it is necessary to return the instrument to
MKS, please obtain an ERA Number (Equipment Return Authorization Number) from the MKS
Calibration and Service Center before shipping. The ERA Number expedites handling and
ensures proper servicing of your instrument.
Please refer to the inside of the back cover of this manual for a list of MKS Calibration and
Service Centers.
Warning All returns to MKS Instruments must be free of harmful,
corrosive, radioactive, or toxic materials.

Customer Support Chapter One: General Information
8
This page intentionally left blank.