MKS 943 Series User manual

Cold Cathode Vacuum Sensor System
Instruction manual part number 100009887
Revision D - May 2020
Series 943
Instruction Manual

© 2020 MKS Instruments, Inc. All rights reserved.
I-Mag®is a registered trademark, and IgniTorrTM and mksinstTM are trademarks of
MKS Instruments, Inc. All other trademarks and registered trademarks are the
properties of their respective owners.
Instruction Manual
Series 943
This instruction manual is for use with Series 943 Cold
Cathode Vacuum Sensor System. A list of applicable
catalog numbers is provided on the following page.
Cold Cathode Vacuum Sensor System
Customer Service / Technical Support:
MKS Global Headquarters
2 Tech Drive, Suite 201
Andover MA, 01810 USA
Phone: [phone]
Email: [email protected]
Visit our website at www.mksinst.com

Series 943 Cold Cathode Vacuum Sensor System
Catalog numbers for Series 943 Cold Cathode Vacuum Sensor System
943-A-120V50-PA-PC
943-A-120V50-TR-NA
943-A-120V50-TR-PC
943-A-120V60-PA-PC
943-A-120V60-TR-PC
943-A-120V60-TR-PC-01
943-A-120V60-TR-PC-02
943-A-120V60-TR-NA
943-A-220V50-PA-PC
943-A-220V50-TR-NA
943-A-220V50-TR-PC
943-A-220V60-PA-PC
943-A-220V60-TR-NA
943-A-220V60-TR-PC
943-A-220V60-PA-PC-02

Series 943 Cold Cathode Vacuum Sensor
Instruction Manual - #100009887
5
Chapter 1 General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.1 Receiving Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.2 International Shipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.3 Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.4 Certification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.5 Customer Service / Technical Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Chapter 2 Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.1 Safety Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.2 Responsibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.3 Grounding Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.4 High Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.5 Over Pressure Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.6 Damage Requiring Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Chapter 3 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.1 General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.2 Intended Use / Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.2.1 Improper Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.3 Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.4 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Chapter 4 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4.1 Mounting the Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4.1.1 AC Power Cord . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4.1.2 Ground the Controller and Vacuum System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4.1.3 Fuse Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
4.1.4 Accessory Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
4.1.5 Logarithmic Analog Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
4.1.6 Buffered Analog Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
4.1.7 Remote High Voltage Enable/Disable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.1.8 Relay Inductive Loads and Arc Suppression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
4.2 Installing a Series 943 System Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
4.2.1 Locating a Cold Cathode Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
4.2.2 Orienting a Cold Cathode Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
4.2.3 Managing Contamination in a Cold Cathode Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
4.2.4 Testing a Cold Cathode Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
4.2.5 Connecting a Cold Cathode Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Chapter 5 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
5.1 Theory of a Cold Cathode Ionization Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
5.2 943 Controller Front / Rear Panels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
5.3 Series 943 Circuit Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
5.3.1 High Voltage Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
5.3.2 Electrometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
5.3.3 Analog Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
5.3.4 Set Point Comparators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
5.3.5 Microprocessor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
5.4 Using the Series 943 System with Gases other than Air or N2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
5.4.1 Calibrating for Other Gases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
5.5 Reading Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
5.6 Set Points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
5.6.1 Adjusting the Set Points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
5.6.2 Protect Set Point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Chapter 6 Service & Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
6.2 Service Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
6.3 Damage Requiring Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Table of Contents

6Series 943 Cold Cathode Vacuum Sensor
Instruction Manual - #100009887
6.4 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
6.5 Contaminated 943 Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
6.5.1 Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
6.5.2 Cleaning the Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
6.5.3 Reassemble the Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
6.6 Customer Service / Technical Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
6.7 Accessories/ Spare Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Chapter 7 Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

1 General Information
7
Series 943 Cold Cathode Vacuum Sensor
Instruction Manual - #100009887
Chapter 1
1General Information
1.1 Receiving Inspection
On receipt of the equipment, inspect all material for damage. Confirm that the shipment includes
all items ordered. If items are missing or damaged, submit a claim as stated below for a domestic or
international shipment, whichever is applicable.
If materials are missing or damaged, the carrier that made the delivery must be notified within 15
days of delivery, or in accordance with Interstate Commerce regulations for the filing of a claim.
Any damaged material including all containers and packaging should be held for carrier inspection.
Contact MKS Instruments, Inc. Customer Support for assistance if your shipment is not correct for
reasons other than shipping damage.
1.2 International Shipment
Inspect all materials received for shipping damage and confirm that the shipment includes all items
ordered. If items are missing or damaged, the airfreight forwarder or airline making delivery to the
customs broker must be notified within 15 days of delivery. The following illustrates to whom the
claim is to be directed.
• If an airfreight forwarder handles the shipment and their agent delivers the shipment to customs,
the claim must be filed with the airfreight forwarder.
• If an airfreight forwarder delivers the shipment to a specific airline and the airline delivers the
shipment to customs, the claim must be filed with the airline.
Any damaged material including all containers and packaging should be held for carrier inspection.
Contact MKS Customer Support for assistance if your shipment is not correct for reasons other than
shipping damage.
1.3 Warranty
MKS Instruments, Inc. provides an eighteen (18) month warranty from the date of shipment for new
MKS Products. The MKS Instruments, Inc. General Terms and Conditions of Sale provides the
complete and exclusive warranty for MKS products. This document is located on our web site at
www.mksinst.com, or may be obtained by contacting an MKS Customer Service Representative.
1.4 Certification
MKS Instruments, Inc. certifies that this product met its published specifications at the time of
shipment from the factory.

1 General Information
8Series 943 Cold Cathode Vacuum Sensor
Instruction Manual - #100009887
1.5 Customer Service / Technical Support
Some minor problems are readily corrected on site. If the product requires service, contact the MKS
Technical Support Department at [phone]. If the product must be returned to the factory
for service, request a Return Material Authorization (RMA) from MKS. Do not return products
without first obtaining an RMA. In some cases a hazardous materials disclosure form may be
required. The MKS Customer Service Representative will advise you if the hazardous materials
document is required.
When returning products to MKS, be sure to package the products to prevent shipping damage.
Shipping damage on returned products as a result of inadequate packaging is the Buyer's
responsibility.
For Customer Service / Technical Support:
MKS Global Headquarters
2 Tech Drive, Suite 201
Andover MA, 01810 USA
Phone: [phone]
Email: [email protected]
Visit our website at: www.mksinst.com

2 Safety
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Series 943 Cold Cathode Vacuum Sensor
Instruction Manual - #100009887
Chapter 2
2Safety
2.1 Safety Introduction
START BY READING THESE IMPORTANT SAFETY INSTRUCTIONS AND NOTES collected here
for your convenience and repeated with additional information at appropriate points throughout
this instruction manual.
These safety alert symbols in this manual or on the Product mean caution - personal safety, property
damage or danger from electric shock. Read these instructions carefully.
This product was designed and tested to offer reasonably safe service provided it is installed,
operated, and serviced in strict accordance with these safety instructions.
Danger indicates a hazardous situation which, if not
avoided, will result in death or serious injury.
Warning indicates a hazardous situation which, if not
avoided, could result in death or serious injury.
Caution indicates a hazardous situation or unsafe
practice which, if not avoided, may result in minor or
moderate personal injury.
Indicates a situation or unsafe practice which, if not
avoided, may result in equipment damage.
Notice
These instructions do not and cannot provide for every contingency that
may arise in connection with the installation, operation, or maintenance of
this product. If you require further assistance, contact MKS.
Safety Precautions
Failure to comply with these instructions may result in serious
personal injury, including death, or property damage.
Always observe and follow all safety notices that are
provided throughout this instruction manual and on the
product.

2 Safety
10 Series 943 Cold Cathode Vacuum Sensor
Instruction Manual - #100009887
These safety precautions must be observed during all phases of operation, installation, and service
of this product. Failure to comply with these precautions or with specific warnings elsewhere in this
manual violates safety standards of design, manufacture, and intended use of the instrument. MKS
disclaims all liability for the customer's failure to comply with these requirements.
•Read Instructions – Read all safety and operating instructions before operating the product.
•Retain Instructions – Retain the Safety and Operating Instructions for future reference.
•Heed Warnings – Adhere to all warnings on the product and in the operating instructions.
•Follow Instructions – Follow all operating and maintenance instructions.
•Accessories – Do not use accessories not recommended in this manual as they may be
hazardous.
2.2 Responsibility
It is the responsibility of the Customer to comply with all local, state, and federal ordinances,
regulations, and laws applicable to the installation, operation and service of this equipment.
It is the responsibility of the end user to provide sufficient lighting at work to meet local regulations.
Operation and Service of this equipment in strict accordance with the methods and procedures
supplied by MKS is the responsibility of the Customer.
MKS assumes no liability, whatsoever, for any personal injuries or damages resulting from the
operation or service of this equipment in any manner inconsistent or contrary to the methods
supplied in MKS literature including, but not limited to, manuals, instructions, bulletins,
communications, and recommendations.
For emergencies and for product safety related matters, contact the MKS Customer Service
Department. See Section 1.5 or Section 6.6 for detailed information regarding how to contact MKS
Customer Service Representatives.
Electrical Shock or Personal Injury
The service and repair information in this manual is for the use
of Qualified Service Personnel. To avoid possible electrical
shock or personal injury, do not perform any procedures in
this manual or perform any servicing on this product unless
you are qualified to do so.
Electrical Shock or Fire
To reduce the risk of fire or electric shock, do not expose this
product to rain or moisture.
Objects and Liquid Entry - Never push objects of any kind into
this product through openings as they may touch dangerous
voltage points or short out parts that could result in a fire or
electric shock. Be careful not to spill liquid of any kind onto the
products.

2 Safety
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Series 943 Cold Cathode Vacuum Sensor
Instruction Manual - #100009887
2.3 Grounding Requirements
See Grounding, Section 4.1.2 in the Installation chapter for more detailed requirements regarding
gauge and system grounding.
Grounding is very important! Be certain that ground circuits are correctly used on your ion gauge
power supplies, gauges, and vacuum chambers, regardless of their manufacturer. Safe operation of
vacuum equipment requires grounding of all exposed conductors of the gauges, the controller and
the vacuum system. LETHAL VOLTAGES may be established under some operating conditions
unless correct grounding is provided.
Ion producing equipment, such as ionization gauges, mass spectrometers, sputtering systems, etc.,
from many manufacturers may, under some conditions, provide sufficient electrical conduction via
a plasma to couple a high voltage electrode potential to the vacuum chamber. If exposed
conductive parts of the gauge, controller, and chamber are not properly grounded, they may attain a
potential near that of the high voltage electrode during this coupling. Potential fatal electrical shock
could then occur because of the high voltage between these exposed conductors and ground.
Proper Grounding
All components of a vacuum system used with this or any
similar high voltage product must be maintained at Earth
ground for safe operation.
Be aware that grounding this product does not guarantee that
other components of the vacuum system are maintained at
Earth ground.
Verify that the vacuum port to which the sensor is mounted is
electrically grounded. It is essential for personnel safety as
well as proper operation that the envelope of the gauge be
connected to a facility ground.
Connect power cords only to properly grounded outlets or
sources.

2 Safety
12 Series 943 Cold Cathode Vacuum Sensor
Instruction Manual - #100009887
2.4 High Voltage
High Voltage is present in the unit when electrical power is applied to the electronics enclosure.
Hazardous voltages may still be present for some time after disconnecting power to the electronics
enclosure. Refer to the Installation and Service chapters for more information.
High Voltage
Be aware that when high voltage is present in any vacuum
system, a life threatening electrical shock hazard may exist
unless all exposed conductors are maintained at Earth ground.
This hazard is not unique to this product.
High Voltage
All conductors in, on, or around the vacuum system that are
exposed to potential high voltage electrical discharges must
either be shielded at all times to protect personnel or must be
connected to Earth ground at all times.
High Voltage
Be aware that an electrical discharge through a gas may
couple dangerous high voltage directly to an ungrounded
conductor almost as effectively as would a copper wire
connection. A person may be seriously injured or even killed
by merely touching an exposed ungrounded conductor at high
potential.
This hazard is not unique to this product.
Do not connect or disconnect any electrical connectors while
power is applied to the equipment (hot swapping). Doing so
may cause damage to the equipment or severe electrical shock
to personnel. This hazard is not unique to this product.

2 Safety
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Series 943 Cold Cathode Vacuum Sensor
Instruction Manual - #100009887
2.5 Over Pressure Conditions
Danger of injury to personnel and damage to equipment exists on all vacuum systems that
incorporate gas sources or involve processes capable of pressuring the system above the limits it
can safely withstand.
For example, danger of explosion in a vacuum system exists during backfilling from pressurized gas
cylinders because many vacuum devices such as ionization gauge tubes, glass windows, glass
belljars, etc., are not designed to be pressurized.
Install suitable devices that will limit the pressure from external gas sources to the level that the
vacuum system can safely withstand. In addition, install suitable pressure relief valves or rupture
disks that will release pressure at a level considerably below that pressure which the system can
safely withstand.
Suppliers of pressure relief valves and pressure relief disks can be located via an online search.
Confirm that these safety devices are properly installed before installing and operating the
product.
Ensure the following precautions are complied with at all times:
(1) the proper gas cylinders are installed,
(2) the gas cylinder valve positions are correct on manual systems,
(3) and the automation is correct on automated gas delivery systems.
Explosive Environment
Do not use the Series 943 Vacuum Sensor System in an
environment of explosive or combustible gases or gas
mixtures. Operation of any electrical instrument in such an
environment constitutes a definite safety hazard. Do not use
the product to measure the pressure of explosive gases or gas
mixtures.
Potential Automatic Operation
It is the installer's responsibility to ensure that the automatic
signals provided by the product are always used in a safe
manner. Carefully check the system programming before
switching to automatic operation.
Vacuum Chamber High Pressures
Where an equipment malfunction could cause a hazardous
situation, always provide for fail-safe operation. As an
example, in an automatic backfill operation where a
malfunction might cause high internal pressures, provide an
appropriate pressure relief device.

2 Safety
14 Series 943 Cold Cathode Vacuum Sensor
Instruction Manual - #100009887
2.6 Damage Requiring Service
Disconnect the product from all power sources and refer servicing to Qualified Service Personnel
under the following conditions:
a. When any cable or plug is damaged.
b. If any liquid has been spilled onto, or objects have fallen into the product.
c. If the product has been exposed to rain or water.
d. If the product does not operate normally even if you follow the operating instructions.
Adjust only those controls that are covered by the operation instructions. Improper
adjustment of other controls may result in damage and will often require extensive work
by a qualified technician to restore the product to its normal operation.
e. If the product has been dropped or the enclosure has been damaged.
f. When the product exhibits a distinct change in performance. This indicates a need for
service.
See Service Guidelines, Section 1.5 for detailed information regarding how to contact MKS
Customer Service Representatives.
Vacuum gauges with compression fittings may be forcefully
ejected if the vacuum system is pressurized.
Notice
Do not substitute parts or modify the instrument.
Because of the danger of introducing additional hazards, do not install
substitute parts or perform any unauthorized modification to the product.
Return the product to a service facility designated by MKS for service and
repair to ensure that safety features are maintained. Do not use this
product if it has unauthorized modifications.
Notice
Safety Check - Upon completion of any service or repairs to this product,
ask the Qualified Service Person to perform safety checks to determine that
the product is in safe operating order.

3 Specifications
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Series 943 Cold Cathode Vacuum Sensor
Instruction Manual - #100009887
Chapter 3
3Specifications
3.1 General Description
The Series 943 Digital, Cold Cathode Vacuum Sensor System provides accurate and reliable data
for processes which need pressure measurement from 10-2 Torr up to 10-10 Torr. The System is easy
to use and is designed for versatility, reliability, and economy.
3.2 Intended Use / Applications
The Series 943 Controller is useful either as a small system controller or as a module in more
sophisticated pressure control environments. The Controller features two standard relay set points
for process applications and a high voltage set point (protect set point) to protect a sensor at higher
pressures.
• Measurement of high vacuum chamber pressures
• Control of high vacuum systems and process sequencing using relay set points
• Sensing abnormal pressure and taking appropriate security measures using relay set points
• Controlling system pressure using analog output as input to an automatic pressure controller
• Starting or stopping system processes with relay set points
• Measuring pressures of backfilled gases
These instruments are to be used only in accordance with the instructions in this operation manual.
3.2.1 Improper Use
• Removal of any factory installed components.
• Modifying any factory installed components.
• Removal of any labeling or warranty seals.
3.3 Storage
• Store the Mini-Ion gauge assembly indoors between -40 oC to +70 oC (-40 0F to 158 0F).
• Bag the assembly in a sealed or shrink wrapped bag with desiccant.
• All of the components should be bagged and boxed together along with the instructions for
future reference.

3 Specifications
16 Series 943 Cold Cathode Vacuum Sensor
Instruction Manual - #100009887
3.4 Specifications
Table 3-1 Specifications for the Series 943 Digital, Cold Cathode Vacuum Sensor
Parameter Specification
Performance
Measurement Range for N2/ Air (1)
Do NOT use this product with
flammable or explosive gases.
Torr: 1.0 x 10-2 to 1.0 x 10-10
mbar: 1.3 x 10-2 to 1.3 x 10-10
Pascal: 1.3 to 1.3 x 10-8
Useful setpoint range Torr: 9.0 x 10-3 to 2.0 x 10-9
mbar: 1.2 x 10-2 to 2.7 x 10-9
Pascal: 1.2 to 2.7 x 10-7
Calibration Gas Air/nitrogen
Physical
Display
Resolution
Units
Update rate
Red LED, 7-segment digits 14 mm in height, ±60° viewing angle
2 digits (1 leading) with 1½-digit signed exponent
Torr, mbar,or Pascal
250 msec
Operating Power 100 to 120 VAC, 50/60 Hz or 230 VAC, 50/60 Hz, 9W
Output Voltage Buffered: 0 to 9 Vdc
Logarithmic: 1 to 9 Vdc (1 V / decade)
Process Controls 2 independent adjustable relay set points
Relay Contact Rating SPDT, 1 A @ 30 VAC or 24 Vdc
Relay Response 50 msec for pressures >10-8 Torr
Case Material Aluminum, anodized
Materials exposed to vacuum 304 stainless steel, platinum, glass, nickel
Weight (with CF Flange) 2.3 lb (1.04 kg)
Insulation Coordination Installation (Overvoltage) Category II, Pollution Degree 2
Dimensions (W x D x H) 3¾" x 7" x 3¾" (96 mm x 178 mm x 96 mm)
Size 1/4 DIN
Typical Weight (with KF Flange) 2.2 lb (1 kg)
Altitude 2000 m (6561 ft) maximum
Operating Temperature 5 ° to 40 °C (41 ° to 104 °F)
Operation Humidity 80% maximum for temperatures less than 31°C, decreasing
linearly to 50% maximum at 40°C
CE Certification EMC Directive
Low Voltage Directive
Sensors
Cold Cathode Sensor Type Series 421 or Series 423 I-MAG®isolated collector, inverted
magnetron
Response Time 40 msec
Reproducibility 5% of indicated pressure at constant temperature
Calibration Gas Air/nitrogen
Installation Orientation Any (port down suggested)
Materials Exposed to Vacuum Series 421 - Stainless steel, Al 6061, silver-copper brazing alloy,
alumina ceramic, Elgiloy®, OFHC®copper Series 423 - SS 302,
SS 304, glass, Al, Inconel®X-750, alumina ceramic
Internal Volume Series 421 - 1.8 in.3(30 cm3)
Series 423 - 0.9 in.3(15 cm3)

3 Specifications
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Series 943 Cold Cathode Vacuum Sensor
Instruction Manual - #100009887
1. Measurements will change with different gases and mixtures. Correction parameters must be used for gases
other than N2or Air.
2. Do NOT use these products with flammable or explosive gases.
Operating Temperature Range 0° to 70°C (32° to 158°F)
Maximum Bakeout Temperature
Without Controller or Cables Series 421 - 250°C (482°F) when backshell subassembly removed, 125°C (257°F)
Series 423 - 500°C (932°F) for CF flange model, magnet removed
Diameter Series 421 - 2.2 in. (56 mm)
Series 423 - 2.6 in. (66 mm)
Length Series 421 - 6.3 in. (160 mm)
Series 423 - 3.4 in. (86 mm)
Typical Weight (with 2¾" CF Flange) 421 - 2.4 lb (1.1 kg)
423 - 1.8 lb (0.8 kg)
Vacuum Connection KF 25, KF 40, 2¾" CF (423 - rotatable), 8 VCR®-F (½"), 1" tubing
Specifications and dimensions are subject to change without notice.
Table 3-1 Specifications for the Series 943 Digital, Cold Cathode Vacuum Sensor
Parameter Specification

3 Specifications
18 Series 943 Cold Cathode Vacuum Sensor
Instruction Manual - #100009887
Notes:

4 Installation
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Series 943 Cold Cathode Vacuum Sensor
Instruction Manual - #100009887
Chapter 4
4Installation
4.1 Mounting the Controller
The Series 943 Controller is designed for either panel mounting or stand-alone use.
An optional hardware kit is available for mounting the Controller into a standard ¼ DIN cutout in a
panel up to 3/16-inch thick (see Section 6.7, Accessories). A dimensioned illustration below shows
the required cutout. Leave at least 3 inches of clearance behind the Controller to accommodate the
connectors and cables.
To mount the Controller into the panel,
1. Slip it through the cutout in the front.
2. Slide the panel mounting brackets into the slots on both sides of the Controller from the rear.
3. Secure them with the thumbscrews provided.
Figure 4-1: 1/4 DIN Panel Mount
Adhesive backed rubber feet for benchtop use are also included in the mounting kit.
1. Remove the adhesive backing from each foot.
2. Apply one to each corner of the aluminum bottom surface.
4.1.1 AC Power Cord
The Series 943 Controller may be ordered with a North American, standard 120 VAC, 50/60 Hz
power cord with a female IEC 320 connector.
If the Controller is ordered without a power cord, use only a harmonized, detachable cord set with
conductors having a cross-sectional area equal to or greater than 0.75 mm2. The power cord should
be approved by a qualified agency such as VDE, Semko, or SEV.
4.1.2 Ground the Controller and Vacuum System.
The Controller is grounded through the ground conductor of the power cord. If the protective
ground connection is lost, all accessible conductive parts may pose a risk of electrical shock. Plug
the cord into a properly grounded outlet only.

4 Installation
20 Series 943 Cold Cathode Vacuum Sensor
Instruction Manual - #100009887
4.1.3 Fuse Replacement
The Series 943 Controller has a combined fuse holder and power inlet on the rear panel. Replace
the fuse following the steps below.
1. Unplug the power cord from the power source and the Controller.
2. Snap out the fuse holder drawer.
3. Replace the fuse(s) with one of the following time-lag fuses:
• T 0.16 A (Ø 5 mm x 20 mm) - 100 to 120 VAC
• T 0.063 A (Ø 5 mm x 20 mm) - 220 to 240 VAC.
4. Close and secure the fuse holder drawer.
4.1.4 Accessory Connector
Relay set point contacts, analog output voltage, and high voltage remote disabling can be accessed
from the Accessory port on the rear panel of the Controller. A connector kit to mate to the port is
provided. The figure and chart below identify the pin functions of the Accessory connector.
Do not exceed the rated line voltage of your unit. Electrical
shock may result.
Table 4-1: 15-Pin D-sub Accessory Connector
Pin # Function
1 Set point relay 1 - normally closed contact
2 Set point relay 1 - common
3 Set point relay 1 - normally open contact
4 Set point relay 2 - normally closed contact
5 Set point relay 2 - common
6 Set point relay 2 - normally open contact
7 not used
8 not used
9 High voltage - disable
10 Ground - high voltage disable
11 Analog output voltage - logarithmic (+)
12 Analog output voltage - logarithmic (-_
13 Analog output voltage - buffered (+)
14 Analog output voltage - buffered (-)
15 not used