MKS 41A User manual

119895-P1
Rev B, 3/98
Instruction Manual
MKS Type 41A, 42A,
51A, and 52A
Mini Vacuum Pressure Switch
Six Shattuck Road
Andover, MA 01810-2449
[phone] or [phone]
Fax: [phone]
E-mail: [e-mail]
Web site: http://www.mksinst.com

WARRANTY
Type 41A, 42A, 51A, and 52A Equipment
MKS Instruments, Inc. (MKS) warrants that for two years from the date of shipment
the equipment described above (the “equipment”) manufactured by MKS shall be
free from defects in materials and workmanship and will correctly perform all date-
related operations, including without limitation accepting data entry, sequencing,
sorting, comparing, and reporting, regardless of the date the operation is performed
or the date involved in the operation, provided that, if the equipment exchanges
data or is otherwise used with equipment, software, or other products of others,
such products of others themselves correctly perform all date-related operations
and store and transmit dates and date-related data in a format compatible with
MKS equipment. THIS WARRANTY IS MKS’ SOLE WARRANTY CONCERNING
DATE-RELATED OPERATIONS.
For the period commencing with the date of shipment of this equipment and ending
two years later, MKS will, at its option, either repair or replace any part which is
defective in materials or workmanship or with respect to the date-related operations
warranty without charge to the purchaser. The foregoing shall constitute the
exclusive and sole remedy of the purchaser for any breach by MKS of this
warranty.
The purchaser, before returning any equipment covered by this warranty, which is
asserted to be defective by the purchaser, shall make specific written arrange-
ments with respect to the responsibility for shipping the equipment and handling
any other incidental charges with the MKS sales representative or distributor from
which the equipment was purchased or, in the case of a direct purchase from MKS,
with the MKS home office in Andover, Massachusetts, USA.
This warranty does not apply to any equipment which has not been installed and
used in accordance with the specifications recommended by MKS for the proper
and normal use of the equipment. MKS shall not be liable under any circumstances
for indirect, special, consequential, or incidental damages in connection with, or
arising out of, the sale, performance, or use of the equipment covered by this
warranty.
MKS recommends that all MKS pressure and flow products be calibrated
periodically (typically every 6 to 12 months) to ensure accurate readings. When a
product is returned to MKS for this periodic re-calibration it is considered normal
preventative maintenance not covered by any warranty.
THIS WARRANTY IS IN LIEU OF ALL OTHER RELEVANT WARRANTIES,
EXPRESSED OR IMPLIED, INCLUDING THE IMPLIED WARRANTY OF
MERCHANTABILITY AND THE IMPLIED WARRANTY OF FITNESS FOR A
PARTICULAR PURPOSE, AND ANY WARRANTY AGAINST INFRINGEMENT OF
ANY PATENT.
11-98 119895-P1

119895-P1
Rev B, 3/98
MKS Type 41A, 42A,
51A, and 52A
Mini Vacuum Pressure Switch

Copyright © 1998 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.
Printed in the United States of America
Baratronis a registered trademark of MKS Instruments, Inc., Andover, MA
Swagelok, VCR, and VCOare registered trademarks of Swagelok Co., Solon, OH
Inconelis a registered trademark of Inco Alloys International, Inc., Huntington, WV

Table of Contents
iii
Table of Contents
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
Customer Support...................................................................................................... 6
Chapter Two: Installation......................................................................................................7
How To Unpack the Type 41/42/51/52 Unit............................................................... 7
Unpacking Checklist ..................................................................................... 7
Product Location and Requirements........................................................................... 8
Setup ......................................................................................................................... 8
Dimensions of the Single-Ended Units.......................................................... 8
Dimensions of the Flow-Through Units......................................................... 10
Mounting ...................................................................................................... 10
Electrical Information................................................................................................ 11
Type “D” Connector...................................................................................... 11
Flying Leads Connector ................................................................................ 12
Trip Point Relay............................................................................................ 12
Interface Cables ......................................................................................................... 13
Connecting a Pressure Switch with a Type “D” Connector............................ 13
Connecting a Pressure Switch with a Flying Leads Cable.............................. 13
Generic Shielded Cable Description .............................................................. 14
Special Consideration for the Ground Connection ......................................... 15
Chapter Three: Overview....................................................................................................... 17
General Information................................................................................................... 17
Labels........................................................................................................................ 17

Table of Contents
iv
Serial Number Label......................................................................................17
Trip Point Label.............................................................................................18
Sensor........................................................................................................................18
Trip Point Value.........................................................................................................19
How The Full Scale Range Affects Trip Point Accuracy................................19
Method of Operation..................................................................................................20
Units Set to Energize Above the Trip Point Pressure ......................................20
Units Set to Energize Below the Trip Point Pressure ......................................21
Hysteresis......................................................................................................21
How A Gage Switch Works........................................................................................22
Reverse Calibration Switch............................................................................22
Atmospheric Switch.......................................................................................22
Chapter Four: Operation ........................................................................................................23
How To Use the Pressure Switch................................................................................23
Chapter Five: Maintenance ....................................................................................................25
General.......................................................................................................................25
Repair ........................................................................................................................25
Appendix A: Product Specifications.......................................................................................27
Performance Specifications ........................................................................................27
Physical Specifications...............................................................................................28
Electrical Specifications .............................................................................................29
Environmental Specifications.....................................................................................29
Appendix B: Model Code Explanation...................................................................................31
Model Code ...............................................................................................................31
Index ......................................................................................................................................37

List of Fi
g
ures and Tables
v
List of Figures and Tables
Figures
Figure 1: Dimensions of High Pressure Single-Ended Units .................................................. 8
Figure 2: Dimensions of Low Pressure Single-Ended Units................................................... 9
Figure 3: Dimensions of Flow-Through Units ....................................................................... 10
Figure 4: Components of a Cable to Connect to a Type “D”Connector................................. 15
Figure 5: Expanded View of the Cable .................................................................................. 15
Figure 6: Flying Leads Connector ......................................................................................... 15
Figure 7: Serial Number Label .............................................................................................. 17
Figure 8: Trip Point Label.....................................................................................................18
Figure 9: Trip Point Set to Energize Above the Trip Point Pressure....................................... 20
Figure 10: Trip Point Set to Energize Below the Trip Point Pressure..................................... 21
Tables
Table 1: Definition of Symbols Found on the Unit .....................................................................2
Table 2: Description of the 41/42/51/52 Mini Vacuum Pressure Switch......................................5
Table 3: Configuration Options of the Single-Ended and Flow-Through Versions......................5
Table 4: Pinout of the 9-Pin Type “D”Connector.....................................................................11
Table 5: Pinout of the Flying Leads Connector.........................................................................12
Table 6: Trip Point Signals.......................................................................................................20

List of Figures and Tables
vi

Safety Information
1
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. 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.

Safet
y
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 (
g
round)
IEC 417, No.5017
Protective earth
(
g
round)
IEC 417, No.5019
Frame or chassis
IEC 417, No.5020 Equipotentiality IEC 417, No.5021 Direct current IEC 417, No.5031 Alternatin
g
current
IEC 417, No.5032
Both direct and
alternatin
g
current
IEC 417, No.5033-a Class ll equipment
IEC 417, No.5172-a
Three phase
alternatin
g
current
IEC 617-2 No.020206
Caution, refer to
accompanyin
g
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

Safety Information
3
Safety Procedures and Precautions
The following general safety precautions must be observed 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 remove instrument covers. Component replacement and internal
adjustments 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 sealing materials.
DO NOT OPERATE IN EXPLOSIVE 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 setup, carefully check all plumbing connections to the
instrument to ensure leak-tight installation.
OPERATE AT SAFE INLET PRESSURES
This unit should never be operated at pressures higher than the rated maximum pressure (refer to
the product specifications for the maximum allowable pressure).

Safet
y
Information
4
INSTALL A SUITABLE BURST DISC
When operating from a pressurized gas source, a suitable burst disc should be installed in the
vacuum system to prevent system explosion should the system pressure rise.
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.

Chapter One: General Information Introduction
5
Chapter One: General Information
Introduction
The MKS Type 41A/42A/51A/52A Mini Vacuum Pressure Switch is based on the proven Type
700/800 Series mini Baratroncapacitance manometer technology. The small footprint of the
41/42/51/52 pressure switch makes it ideal for applications with limited space. The switches are
available in a single-ended or flow-through configuration, using either an absolute or gage
transducer. Table 2 lists the various configurations available. Table 3 lists the features available
on the single-ended (41 and 51) and flow-through versions (42 and 52).
Description of the 41/42/51/52 Mini Vacuum Pressure Switch
Model Type Description
41 Single-Ended Gage Transducer
51 Single-Ended Absolute Transducer
42 Flow-Through Gage Transducer
52 Flow-Through Absolute Transducer
Table 2: Description of the 41/42/51/52 Mini Vacuum Pressure Switch
Configuration Options of the Single-Ended and Flow-Through Versions
Feature Single-Ended (41 and 51) Flow-Through (42 and 52)
Connector 9-pin Type “D”or flying leads 9-pin Type “D”or flying leads
Fittings 4-VCR fixed male, ¼” NPT male,
¹/8”NPT male, or KF-16 Swagelok®4-VCR fixed male
Full Scale Range 10 Torr to 25000 Torr (500 psi) 1000 Torr (≈20 psi) to 500 psi
Table 3: Configuration Options of the Single-Ended and Flow-Through Versions
The pressure switch output signal changes state when the measured pressure crosses a trip point
pressure value. The trip point pressure value is selected at the time the unit is ordered and the
value set at the factory. The trip point direction, whether to trip when the pressure rises above or
drops below the trip point value, is also defined when the unit is ordered. The pressure switch
arrives fully configured so all you need to do is install it into your system.

How This Manual is Organized Cha
p
ter One: General Information
6
How This Manual is Organized
This manual is designed to provide instructions on how to set up, install, and operate a Type
41/42/51/52 unit.
Before installing your 41/42/51/52 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 instrument and explains all the functions and
features.
Chapter Five, Maintenance, lists any maintenance required to keep the instrument in good
working condition.
Appendix A, Product Specifications, lists the specifications of the instrument.
Appendix B, Model Code Explanation, describes the model code.
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
41/42/51/52 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.

Chapter Two: Installation How To Un
p
ack the T
yp
e 41/42/51/52 Unit
7
Chapter Two: Installation
How To Unpack the Type 41/42/51/52 Unit
MKS has carefully packed the Type 41/42/51/52 unit 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 MKS immediately. If it is necessary to return the
unit to MKS, obtain an ERA Number (Equipment Return Authorization Number) from the MKS
Service Center before shipping. Please refer to the inside of the back cover of this manual for a
list of MKS Calibration and Service Centers.
Caution Only qualified individuals should perform the installation and any
user adjustments. They must comply with all the necessary ESD and
handling precautions while installing and adjusting the instrument.
Proper handling is essential when working with all highly sensitive
precision electronic instruments.
Unpacking Checklist
Standard Equipment:
•Type 41/42/51/52 Unit
•Type 41/42/51/52 Instruction Manual (this book)
Optional Equipment:
•Electrical Connector Accessories Kit - XXA-K1 where XX designates your specific
model (contains a mate for the electrical connector)
•Interface cable CB41S-1

Product Location and Requirements Cha
p
ter Two: Installation
8
Product Location and Requirements
•Ambient Operating Temperature: 0°to 50°C (32°to 122°F)
•Ventilation requirements include sufficient air circulation
•Storage Temperature Range: -20°to +80°C (-4°to 176°F)
•Input power: 10 to 20 VDC @ 35 mA maximum or 20 to 30 VDC @ 30 mA maximum
Setup
Dimensions of the Single-Ended Units
Note All dimensions are listed in inches with millimeters referenced in
parentheses.
The dimensions of single-ended units depend upon the full scale range of the unit. High pressure
units have a full scale range of 50 psi through 500 psi (2600 Torr through 25000 Torr). Low
pressure units have a full scale range of 10 through 1200 Torr.
Hi
g
h Pressure Units
Ran
g
es 50 psi (2600 Torr) throu
g
h 500 psi
1.50 (38.1) DIA
2.20 (55.9)
0.19 (4.7)
0.31 (7.9)
0.63 (16.0)
4-VCR fittin
g
fixed male
0.32 (8.0)
0.62 (15.9)
Hex Flat
A
0.40 (10.2) for 1/8 NPT
0.58 (14.7) for 1/4/NPT
A =
Figure 1: Dimensions of High Pressure Single-Ended Units

Chapter Two: Installation Setu
p
9
Low Pressure Units 10 through 1200 Torr
1.50 (38.1) Dia.
0.19 (4.8)
1.84 (46.6)
0.99 (25.1) 4-VCR Fixed
Male Fitting
0.62 Hex Flat
Typ
0.92 (23.4)
1/4" NPT Male
0.34 (8.6) Typ
1/8" NPT Male
0.74
(18.8) 0.46
(11.8)
KF-16
Optional Fittings:
Figure 2: Dimensions of Low Pressure Single-Ended Units

Setup Cha
p
ter Two: Installation
10
Dimensions of the Flow-Through Units
Note All dimensions are listed in inches with millimeters referenced in
parentheses.
The dimensions of the flow-through version are the same for high and low pressure units.
1.50 (38.1) Dia
2.45 (62.2)
0.19 (4.8)
0.38 (9.5)
2.25 (57.2)
4-VCR Male Fittin
g
Matin
g
4-VCR Connector
(customer supplied)
0.43 (11.0) Ref
Figure 3: Dimensions of Flow-Through Units
Mounting
The 41/42/51/52 switch can be mounted in any orientation with the exception of the low pressure
units (< 20 psi FS). If the full scale pressure of the unit is less than 20 psi and the unit may be
exposed to particulates, mount the unit with the connector up. This will allow any foreign matter
entering the unit to fall away from the sensing diaphragm. Material on the diaphragm may cause
a zero shift and reduce the unit's switch point accuracy.

Chapter Two: Installation Electrical Information
11
Electrical Information
The 41/42/51/52 switches require an external power supply capable of supplying either
10 to 20 VDC @ 35 mA maximum or 20 to 30 VDC @ 30 mA maximum.
Type “D” Connector
The pressure switch is available with a 9-pin male Type “D”connector. The connector pinout is
listed in Table 4.
Pinout of the 9-Pin Type “D”Connector
Pin Number Assignment
1 Power Return (-)
2 Power Input (+)
3 Relay Normally Open Contact
4 Relay Common
5 Relay Normally Closed Contact
6 Reserved
7 Reserved
8 Reserved
9 Chassis Ground
Table 4: Pinout of the 9-Pin Type “D”Connector
Note The “Reserved”
p
in assi
g
nment refers to a
p
in with an internal connection
that may be assigned a function in the future.

Electrical Information Cha
p
ter Two: Installation
12
Flying Leads Connector
The flying leads connector has 2 foot long cable with six (6) leads. The color assignments are
listed in Table 5.
Pinout of the Flying Leads Connector
Wire Assignment
Red Power Input (+)
Black Power Return (-)
Green Relay Normally Open Contact
White Relay Common
Orange Relay Normally Closed Contact
Bare Wire Shield (Drain)
Table 5: Pinout of the Flying Leads Connector
Trip Point Relay
The trip point relay is a single pole, double throw switch, one normally open (NO), one normally
closed (NC) form “C”relay with contacts rated from 0.1 to 1 ampere, resistive. When the relay
is energized the normally open (NO) contacts will close. The action of the trip point, whether it
is energized above or below the trip point, is specified when the unit is ordered. Refer to
Appendix B: Model Code Explanation, page 31, to determine the trip point action from the
model code of the unit. In addition, the serial number label, shown in Figure 7, page 17, lists the
trip point action.