MKS 937B Series User manual

Series 937B Vacuum System Controller
Operation and Maintenance Manual
Instruction Manual p/n: 100016467
Rev F, August 2020

937B Controller Instruction Manual pg. 2
Table of Contents
1Safety Information.............................................................................................................................5
1.1 Symbols Used in this Manual and their definitions .......................................................................................5
1.2 Safety Precautions .......................................................................................................................................5
2Specifications....................................................................................................................................7
2.1 Controller......................................................................................................................................................7
2.2 Pressure Sensors.........................................................................................................................................9
2.3 Controller Display.......................................................................................................................................13
2.3.1 Display Message ......................................................................................................................................................13
2.3.2 Display Resolutions ..................................................................................................................................................14
2.3.3 Serial Communication Response Format..................................................................................................................15
3Feature, Control Locations and Dimensions ..................................................................................16
4Typical Applications for the Series 937B Controller.......................................................................18
5MKS Series 937B Vacuum System Controller ...............................................................................19
6Operating the Series 937B Controller.............................................................................................21
6.1 Power.........................................................................................................................................................21
6.2 Front Panel Control Lock............................................................................................................................21
6.3 Front Panel Display....................................................................................................................................21
6.3.1 Standard Front Panel Display ...................................................................................................................................21
6.3.2 Large Font Display....................................................................................................................................................22
6.4 System Setup.............................................................................................................................................23
6.4.1 Overview of 937B System Setup...............................................................................................................................23
6.4.2 Display System Setup Parameters............................................................................................................................23
6.4.3 Change and Save a Parameter Value.......................................................................................................................24
6.4.4 Description of the System Setup Parameters............................................................................................................25
6.5 Channel Setup for Pressure Measurement ................................................................................................28
6.5.1 Overview of 937B Channel Setup.............................................................................................................................28
6.5.2 Setup for a Capacitance Manometer.........................................................................................................................30
6.5.3 Setup for a CP (Convection Pirani), Convectron, or PR Sensor ................................................................................32
6.5.4 Setup a Cold Cathode Sensor...................................................................................................................................35
6.5.5 Setup a Hot Cathode Sensor....................................................................................................................................38
6.6 Power Control of a Pressure Sensor..........................................................................................................42
6.6.1 Power (including degas) Control of a Sensor using Front Panel Control Button ........................................................42
6.6.2 Power (including degas) Control of a Sensor via 37 pin AIO D-sub Connector..........................................................43
6.6.3 Power (including degas) Control of a Sensor using Serial Communication Commands..................................................44
6.7.2 Procedures for a leak test with the 937B...................................................................................................................44
7Installing Vacuum Sensors.............................................................................................................46
7.1 Over Pressure Conditions ..........................................................................................................................46
7.2 Installing Cold Cathode Sensors................................................................................................................46
7.2.1 Locating a Cold Cathode Sensor ..............................................................................................................................46
7.2.2 Orienting a Cold Cathode Sensor .............................................................................................................................46
7.2.3 Managing Contamination in a Cold Cathode Sensor.................................................................................................47
7.2.4 Connecting the Series 431/422 Sensor.....................................................................................................................47
7.2.5 Connecting the 423 I-Mag Sensor.............................................................................................................................47
7.3 Installing Hot Cathode Sensors..................................................................................................................47
7.3.1 Locating a Hot Cathode Sensor................................................................................................................................47
7.3.2 Preventing Contamination in a Hot Cathode Sensor .................................................................................................47
7.3.3 Orienting a Hot Cathode Sensor...............................................................................................................................47
7.3.4 Connecting a Hot Cathode Sensor to the Vacuum System .......................................................................................48
7.3.5 Connecting a Hot Cathode Sensor to the 937B Controller.........................................................................................48
7.4 Installing Convection Pirani, Convectron, or Pirani Sensors.......................................................................49
7.4.1 Locating the Sensor..................................................................................................................................................49
7.4.2 Preventing Contamination in a Pirani Sensor............................................................................................................49
7.4.3 Orienting the Series 317Convection Pirani or Convectron Sensor.............................................................................49
7.4.4 Orienting the Series 345 Pirani Sensor .....................................................................................................................50
7.4.5 Connecting Convection Pirani, Convectron, or Pirani Sensors..................................................................................50
7.4.6 Preparing the 317 Sensor for Bakeout ......................................................................................................................51
7.5 Installing Capacitance Manometers - MKS Baratron..................................................................................51
7.5.1 Installing a Capacitance Manometer.........................................................................................................................51
7.5.2 Connecting a Capacitance Manometer .....................................................................................................................51
7.6 Series 902B Piezo......................................................................................................................................52

937B Controller Instruction Manual pg. 3
8Connecting Relay and Analog Outputs ..........................................................................................53
8.1 Connecting 937B Relay Outputs.....................................................................................................................53
8.1.1 Pin Out for the 937B Relay Output............................................................................................................................53
8.1.2 Proper Setting of a Relay..........................................................................................................................................54
8.1.3 Relay Inductive Loads and Arc Suppression.............................................................................................................55
8.2 Connecting the 937B Analog Output..........................................................................................................55
8.2.1 Buffered Analog Output ............................................................................................................................................56
8.3 Logarithmic/Linear and Combination Analog Output..................................................................................67
8.3.1 Logarithmic/Linear Analog Output.............................................................................................................................67
8.3.2 Combination Analog Output......................................................................................................................................67
8.3.3 Logarithmic/Linear Analog Output when the Sensor Power is Turned OFF...............................................................69
9RS232/485 Serial Communication Commands..............................................................................70
9.1 Serial Communication Wiring Diagram.......................................................................................................70
9.2 Communication Protocols...........................................................................................................................70
9.3 Pressure Reading Commands ...................................................................................................................71
9.4 Relay and Control Setting Commands.......................................................................................................72
9.5 Capacitance Manometer Control Commands.............................................................................................73
9.6 Convection Pirani, Convectron and Pirani Control Commands..................................................................73
9.7 Cold Cathode Control Commands..............................................................................................................74
9.8 Hot Cathode Control Commands ...............................................................................................................75
9.9 System Commands....................................................................................................................................76
9.10 Error Codes................................................................................................................................................78
9.11 937B ProfiBus communicationprotocol and commands .............................................................................79
9.11.3 937B PROFIBUS output buffer map..........................................................................................................................81
10 Maintenance of Series 937B Controller Modules...........................................................................86
10.1 Removing and Installing a Sensor Module.................................................................................................86
10.2 Removing and Installing AIO Module .........................................................................................................87
10.3 Removing and Installing Profibus Control Module......................................................................................88
10.4 Mounting the Controller..............................................................................................................................89
10.5 AC Power Cord ..........................................................................................................................................90
11 Maintenance and Service of MKS Vacuum Sensors......................................................................91
11.1 422, 423 and 431 Cold Cathode Sensors ..................................................................................................91
11.2 Maintenance of Series 431/422 Cold Cathode Sensor...............................................................................92
11.2.1 Disassemble the Series 431/422 Sensor...................................................................................................................92
11.2.2 Cleaning the Series 431/422 Sensor.........................................................................................................................94
11.2.3 Assemble the Series 431/422 Sensor.......................................................................................................................94
11.2.4 Preparing the Sensor for Bakeout.............................................................................................................................95
11.2.5 Testing a Cold Cathode Sensor................................................................................................................................95
11.3 Maintenance of Series 423 I-Mag Cold Cathode Sensor............................................................................95
11.3.1 Disassemble the I-Mag Sensor.................................................................................................................................95
11.3.2 Clean the I-Mag Sensor............................................................................................................................................97
11.3.3 Assemble the I-Mag Sensor......................................................................................................................................97
11.3.4 Preparing the Sensor for Bakeout.............................................................................................................................98
11.4 Maintenance of Low Power Nude and Mini BA Hot Cathode Sensors .......................................................98
Hot Cathode Theory .................................................................................................................................................................98
11.4.1 Cleaning the Hot Cathode Sensor.............................................................................................................................99
11.4.2 Testing the Hot Cathode Sensor...............................................................................................................................99
11.5 Maintenance of a Pirani Sensor ...............................................................................................................100
Theory of a Pirani Pressure Sensor........................................................................................................................................100
11.5.1 Cleaning the Series 345 Sensor..............................................................................................................................101
11.5.2 Testing the Series 345 Sensor................................................................................................................................101
11.5.3 Cleaning the Series 317 Sensor..............................................................................................................................102
11.5.4 Testing the Series 317 Sensor................................................................................................................................102
11.5.5 Testing the Series 275 Convectron Sensor.............................................................................................................102
11.6 Maintenance of a Capacitance Manometer..............................................................................................103
Theory of a Capacitance Manometer......................................................................................................................................103
Repairing the Baratron Capacitance Manometer ....................................................................................................................103
12 Spare Parts and Accessories .......................................................................................................104

937B Controller Instruction Manual pg. 4
Package Contents
Before unpacking the 937B Controller, check all surfaces of the packing material for shipping
damage. Check to be sure that the 937B system contains the following items:
•1 Series 937B Controller (with selected modules installed)
•1 female, 25-pin D-sub connector for relay output connection
•1 male, 37pin D-sub connector for analog output connection
•1 10-foot power cord (US customer only)
Service and Warranty Guidelines
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: [e-mail]
Visit our website at: www.mksinst.com
Warranty Information
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 provide 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 a contacting an MKS customer service representative.
© 2020, MKS Instruments, Inc. All rights reserved. Granville-Phillips®, Baratron®, Convectron®, and I-Mag®are
registered trademarks, and mksinstTM is a trademark of MKS Instruments, Inc. All other trademarks and registered
trademarks are the properties of their respective owners.

937B Controller Instruction Manual pg. 5
1 Safety Information
1.1 Symbols Used in this Manual and their definitions
CAUTION: Risk of electrical shock.
CAUTION: Refer to manual. Failure to read message could result
in personal injury or serious damage to the equipment or both.
CAUTION: Hot surface.
Calls attention to important procedure, practice, or conditions.
Failure to read message could result in damage to the equipment.
1.2 Safety 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 for the 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.
Properly Ground the Controller.
This product is grounded through the grounding conductor of the power cord. To avoid electrical shock,
plug the power cord into a properly wired receptacle before connecting it to the product input terminals. A
protective ground connection through the grounding conductor in the power cord is essential for safe
operation.
Upon loss of the protective-ground connection, all accessible conductive parts (including knobs and
controls that may appear to be insulating) can render an electrical shock.
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, however, that grounding this product does
not guarantee that other components of the vacuum system are maintained at earth ground. Connecting
the power cable only to a properly grounded outlet is necessary but not sufficient for safe operation of a
vacuum system with this or any similar high voltage producing product. Verify that the vacuum port to
which the sensors are mounted is electrically grounded.

937B Controller Instruction Manual pg. 6
Some of the sensors operated by the 937B Controller are highly gas sensitive and were calibrated
with a specific gas. When used with other gases, the true pressure could be much higher than the
indicated pressure. Read and understand the information provided in this manual about setting up,
installing and operating each sensor type with different gases.
Do not substitute parts or modify the 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.
Use proper electrical fittings.
Dangerous voltages are contained within this instrument. All electrical fittings and cables must be of the
type specified, and in good condition. All electrical fittings must be properly connected and grounded.
The Series 937B Controller contains lethal voltages when on.
High voltage is present in the cable and a Cold Cathode sensor when the Controller is turned on.
Use the proper power source.
This product is intended to operate from a power source that applies a voltage between the supply
conductors, or between either of the supply conductors and ground, not more than that specified in the
manual.
Use the proper fuse.
Only use a fuse of the type, voltage rating, and current rating specified for your product.
Do not operate in explosive environment.
To avoid explosion, do not operate this product in an explosive environment unless it has been specially
certified for such operation.
Service by qualified personnel only.
Operating personnel must not remove instrument covers. Component replacement and internal
adjustments must only be made by qualified service personnel.
Use proper power cord.
Only use a power cord that is in good condition and that meets the input power requirements specified in
the manual.
Only use a detachable cord set with conductors having a cross-sectional area equal to or greater than
0.75 mm2. The power cable should be approved by a qualified agency such as VDE, Semko, or SEV.

937B Controller Instruction Manual pg. 7
2 Specifications
1
2.1 Controller
Pressure measuring range
2
1 x 10-11 to 1.0 x 10+4 Torr
1 x 10-11 to 1.3 x 10+4 mbar
1 x 10-9 to 1.3 x 10+6 Pa
Relay set point range
3
CC (Cold Cathode) 2.0 x 10-10 to 5.0 x 10-3 Torr
2.7 x 10-10 to 6.5 x 10-3 mbar
2.7 x 10-8 to 6.5 x 10-1 Pa
HC (Hot Cathode) 5.0 x 10-10 to 5.0 x 10-3 Torr
6.5 x 10-10 to 6.5 x 10-3 mbar
6.5 x 10-8 to 6.5 x 10-1 Pa
Pirani 2.0 x 10-3 to 9.5 x 10+1 Torr
2.7 x 10-3 to 1.2 x 10+2 mbar
2.7 x 10-1 to 1.2 x 10+4 Pa
CP (Convection Pirani 2.0 x 10-3 to 9.5 x 10+2 Torr
or Convectron) 2.7 x 10-3 to 1.2 x 10+3 mbar
2.7 x 10-1 to 1.2 x 10+5 Pa
CM (Absolute Manometer) 0.2% to 100% of the measurement range of the head (e.g. 1 Torr
head is 2.0 x 10-3 to 1.0 x 10+0 Torr)
Allowed range within which a control sensor may switch on a Cold or Hot Cathode
Pirani 5.0 x 10-4 to 9.5 x 10-1 Torr
6.5 x 10-4 to 1.3 x 10-1 mbar
6.5 x 10-2 to 1.3 x 101Pa
CP (Convection Pirani) 2.0 x 10-3 to 1.0 x 10-2 Torr
2.7 x 10-3 to 1.3 x 10-1 mbar
2.7 x 10-1 to 1.3 x 101Pa
CM (≤2T head) 1.0 x 10-1 to 0.2% of FS Torr
1.3 x 10-1 to 0.2% of FS mbar
1.3 x 10+1 to 0.2% of FS Pa
Protection set point
4
CC & HC 1.0x10-5 to 1.0x10-2 Torr, default setting: 5.0x10-3 Torr
Operating temperature range 5° to 40°C (41° to 104°F)
1
Specifications subject to change without notice.
2
The measurement range depends upon the sensor options selected.
3
Relay set point values are automatically adjusted when pressure unit is changed.
4
The protection set point is always enabled in 937B.

937B Controller Instruction Manual pg. 8
Storage temperature range -10° to 55°C (14° to 131°F)
Relative humidity 80% maximum for temperatures less than 31°C, decreasing
linearly to 50% maximum at 40°C
Altitude 2000 m (6561 ft) maximum
Insulation coordination Installation (Over-voltage) Category II, Pollution Degree 2
Power requirement (nominal) 100 - 240 VAC, 50/60 Hz
Mains voltage Fluctuations not to exceed ±10% of nominal
Power consumption 150 W maximum
Fuse rating, size 2X2A, 250V, Ø 5 mm x 20 mm
Process control relay 12 nonvolatile relays, (4 for each sensor module)
Relay rating SPDT, 2 A @ 30 V resistive
Relay response 150 msec maximum
Analog outputs
5
One Buffered and one Logarithmic (V = A × Lg(p) + B) or Linear
(V = A × p) for each channel, up to two (2) wide-range
combination logarithmic outputs. Output impedance = 100 ohms
Number of channels Up to 6
Front panel controls Power ON-OFF switch, keypad for setup and operational
commands.
Display 320x240 color LCD with back lighting.
Pressure units Torr, mbar, Pascal or microns
Update rate LCD display is updated 3 times per second. The pressure
signals are updated every 50 msec.
Sensor module slots 3
Sensor modules channels/module
Cold Cathode single
Hot Cathode single
Pirani/Convection Pirani dual
Capacitance Manometer dual
COM modules Profibus (optional)
Computer interface Serial –RS-232 and RS-485 (standard); 9600, 19200, 38400,
57600,115200 baud rate selectable
Electronic casing Aluminum
Dimensions (W x D x H) 9½" x 12¼" x 3½" (241 mm x 311 mm x 88 mm)
Size ½ rack, 2U high
5
Logarithmic/linear and combined logarithmic analog outputs can be customized using the system setup
menu.

937B Controller Instruction Manual pg. 9
Typical weight 8.0 lb (3.6 kg)
CE certification EMC Directive: 2004/108/EEC
Low Voltage Directive: 73/23/EEC
2.2 Pressure Sensors
Sensor type
CC (Cold Cathode) Series 431 and 422 inverted magnetron
Series 423 I-Mag
HC (Hot Cathode) Bayard-Alpert (BA) type ionization sensors including MKS MIG
(Miniature Ionization Gauge), or LPN (Low Power Nude)
Pirani Series 345 Pirani
CP (Convection Pirani) Series 317 Convection Pirani
Series 275 Convectron®
CM (Capacitance Manometer) MKS unheated Baratron®or MKS 45 C heated Baratron, with
suitable cable connections and full-scale ranges. Each CM
module operates up to two Capacitance Manometers, and the
total current requirement of operating sensor(s) must be 1 amp
or less.
Pressure measurement ranges
CC (Cold Cathode) 1.0 x 10-11 to 1.0 x 10-2 Torr
1.3 x 10-11 to 1.3 x 10-2 mbar
1.3 x 10-9 to 1.3 x 10+0 Pa
HC (Hot Cathode) 1 .0x 10-10 to 1.0 x 10-2 Torr
1.3 x 10-10 to 1.3 x 10-2 mbar
1.3 x 10-8 to 1.3 x 10+0 Pa
Pirani 5.0 x 10-4 to 4.0 x 10+2 Torr
6.5 x 10-4 to 5.2 x 10+2 mbar
6.5 x 10-2 to 5.2 x 10+4 Pa
CP / (or Convectron) 1.0 x 10-3 to 1.0 x 10+3 Torr
1.3 x 10-3 to 1.3 x 10+3 mbar
1.3 x 10-1 to 1.3 x 10+5 Pa
CM (Capacitance Manometer) Three decades below full scale of head, (e.g., 10 Torr head is
1.0 x 10-2 to 1.0 x 10+1 Torr)
Response time (Buffered analog output)
CC <40 msec
6
HC <50 msec
Pirani, CP <80 msec
CM <40 msec
Response time (Log/Lin analog output)
CC <50 msec
6
A fast response (<10 msec) Cold Cathode module is also available. Consult MKS for details.

937B Controller Instruction Manual pg. 10
HC <50 msec
Pirani, CP <80 msec
CM <80 msec
Resolution
7
CC 2 significant digits between 10-10 and 10-2 Torr, 1 significant digit
in 10-11 Torr decade
HC 2 significant digits between 10-9 and 10-2 Torr; 1 significant digit
in 10-10 Torr decade
Pirani 1 significant digit from 450 to 100 Torr; 2 significant digits
between 10-4 and 100 Torr
CP, Convectron 2 significant digits over the entire range.
CM 4 significant digits from 10 to 100% FS, 3 significant digits from 1
to 10% FS, 2 significant digits from 0.1 to 1% FS, 1 significant
digit from 0.01 to 0.1% FS.
Repeatability
CC, HC, Pirani, CP 5% of indicated pressure at constant temperature
CM 0.25% of indicated pressure at constant temperature
Calibration gas
CC, HC Nitrogen, Argon
Pirani, CP Air/nitrogen, Argon, Helium
CM Any (gas independent)
Installation orientation
CC, HC, CM, Pirani, Any (port down suggested)
CP Body horizontal only
Materials exposed to vacuum may include
CC Series 431 and 422 –SS 304, Al 6061, silver-copper brazing
alloy, alumina ceramic, Elgiloy®, OFHC®copper
Series 423–SS 302, SS 304, glass, Al, Inconel X-750, alumina
ceramic
HC 304 SS, Inconel®X750®, glass, tungsten, platinum clad
molybdenum, tantalum, nickel, braze alloy, either yttria coated
iridium or tungsten filament
Pirani 300 series stainless, platinum, glass, alumina ceramic, silver
brazing alloy, nickel 200
CP 300 series stainless, nickel, glass, platinum
7
Trailing zeros displayed on LCD screen do not reflect the resolution of the pressure reading.