MKS MODUCELL 325 Series User manual

MODUCELL®Pirani Vacuum
Sensor/Transducer
Instruction manual part number 103250029
Revision B- May 2020
Series 325
Instruction Manual

© 2020 MKS Instruments, Inc. All rights reserved.
MODUCELL®is a registered trademark and mksinstTM is a trademark of MKS Instruments,
Inc. All other trademarks and registered trademarks are the properties of their respective
owners.
Instruction Manual
Series 325
This instruction manual is for use with Series 325
MODUCELL®Pirani Vacuum Sensor/Transducer.
MODUCELL®Pirani Vacuum
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 325 Moducell Vacuum Sensor
Instruction Manual - #10325002
3
Chapter 1 General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.1 Receiving Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.2 International Shipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.3 Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.4 Certification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.5 Customer Service / Technical Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.6 Typical Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Chapter 2 Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.1 Safety Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2 Responsibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.3 Grounding Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.4 High Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.5 Over Pressure Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.6 Damage Requiring Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Chapter 3 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.1 General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.2 Intended Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.2.1 Improper Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.3 Transportation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.4 Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.5 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Chapter 4 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.1 Sensor Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.2 Connect the Sensor to the Vacuum System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.3 Electrical Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.3.1 Input/Output Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.3.2 Inductive Loads and Arc Suppression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.3.3 Adjust the Set Point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Chapter 5 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
5.1 Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
5.1.1 Theory of the Thermal Conductivity Gauge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
5.1.2 Bridge Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
5.1.3 Voltage Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
5.1.4 Comparator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
5.1.5 Open Filament Detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
5.2 Measuring Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
5.3 Gas Other than Air or Nitrogen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
5.3.1 Nitrogen Equivalent Pressure and Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
5.3.2 Calibrating for Gases Not Shown in the Graph or Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
5.3.3 Detecting Leaks in the System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
5.4 Using the MODUCELL with a Computer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
5.4.1 Analog-to-Digital Converter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
5.4.2 Equations to Convert Voltage to Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
5.5 Energy Transfer and Measurement Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
5.5.1 The Energy Transfer Equation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
5.5.2 Measurement Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Chapter 6 Service & Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
6.1 Customer Service / Technical Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
6.2 Service Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
6.3 Damage Requiring Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
6.4 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
6.5 Cleaning the MODUCELL Case and Sensor Tube . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
6.5.1 Venting to Atmosphere . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
6.6 Testing the Sensor Tube . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Table of Contents

4Series 325 Moducell Vacuum Sensor
Instruction Manual - #103250029
6.7 Replacing the Sensor Tube . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
6.7.1 Disassemble the MODUCELL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
6.7.2 Reassemble the MODUCELL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Chapter 7 Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

1 General Information
5
Series 325 Moducell Vacuum Sensor
Instruction Manual - #103250029
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
6Series 325 Moducell Vacuum Sensor
Instruction Manual - #103250029
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 due to 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
1.6 Typical Applications
for the MODUCELL Pirani Vacuum Sensor/Transducer
• Measuring foreline and roughing pressures generated by mechanical vacuum pumps
• Controlling valves and pumps to automate system pump down using the relay set point
• Sensing abnormal pressure and taking appropriate security measures using the relay set
point
• Controlling system pressure using the analog output as input to an automatic pressure
controller
• Starting or stopping system processes using the relay set point
• Activating high vacuum sensors in their operating range

2 Safety
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Series 325 Moducell Vacuum Sensor
Instruction Manual - #103250029
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
8Series 325 Moducell Vacuum Sensor
Instruction Manual - #103250029
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 6.1 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 325 Moducell Vacuum Sensor
Instruction Manual - #103250029
2.3 Grounding Requirements
See Grounding, Section 4.1 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 Series 342/343 Mini-
Ion Gauge Module 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
10 Series 325 Moducell Vacuum Sensor
Instruction Manual - #103250029
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.