Varian sentorr User manual

senTorr™
Gauge
Controller
Instruction Manual
Varian Vacuum Technologies
121 Hartwell Avenue
Lexington, Massachusetts 02421
[phone]
Manual No. 6999-08-165
Revision G
February 1999

Telephone Numbers
U.S. only 1-800-8-VARIAN (1-800-882-7426)
From Alaska and Hawaii, dial [phone]
Order Entry (Sales)............Press 1........FAX [phone]
Technical Support............Press 2........FAX [phone]
Field Service............Press 3........FAX [phone]
Training (Information
and Registration)............Press 4........FAX [phone]
Service
Canada
Telephone ..................1-800-663-2727 (Canada Only)
[phone]
FAX ..................[phone]
France
Telephone ..................(33) 16-986-3838
FAX ..................(33) 16-928-2308
Germany (Darmstadt)
Telephone ..................(49) 61-51-70-32-05
FAX ..................(49) 61-51-70-32-79
Italy
Telephone ..................(39) 11-997-9111
FAX ..................(39) 11-997-9350
Japan
Telephone ..................(81) 3-3588-9732
FAX ..................(81) 3-3449-4597
Korea
Telephone ..................(82) 3-333-665-5171
FAX ..................(82) 3-333-665-0115
UK
Telephone ..................(44) 932-234-741
FAX ..................(44) 932-228-769
Copyright © by Varian Associates, Inc.
Reserved, including the right of reproduction in whole or in part in any form, without
permission in writing from Varian Vacuum Products, Lexington, MA 02421
November, 1995

WARRANTY
Products manufactured by Seller are warranted against defects in materials and workmanship for
twelve (12) months from date of shipment thereof to Customer, and Seller’s liability under valid war-
ranty claims is limited, at the option of Seller, to repair, replacement, or refund of an equitable portion
of the purchase price of the Product. Items expendable in normal use are not covered by this warranty.
All warranty replacement or repair of parts shall be limited to equipment malfunctions which, in the
sole opinion of Seller, are due or traceable to defects in original materials or workmanship. All obliga-
tions of Seller under this warranty shall cease in the event of abuse, accident, alteration, misuse, or
neglect of the equipment.In-warranty repaired or replacement parts are warranted only for the remain-
ing unexpired portion of the original warranty period applicable to the repaired or replaced parts.After
expiration of the applicable warranty period, Customer shall be charged at the then current prices for
parts, labor, and transportation.
Reasonable care must be used to avoid hazards.Seller expressly disclaims responsibility for loss or
damage caused by use of its Products other than in accordance with proper operating procedures.
When products are used with toxic chemicals, or in an atmosphere that is dangerous to the health of
humans, or is environmentally unsafe, it will be the responsibility of the Customer to have the product
cleaned by an independent agency skilled and approved in handling and cleaning contaminated mate-
rials before the product will be accepted by Varian Associates for repair and/or replacement.
Except as stated herein, Seller makes no warranty, express or implied (either in fact or by operation of
law), statutory or otherwise; and, except as stated herein, Seller shall have no liability under any war-
ranty, express or implied (either in fact or by operation of law), statutory or otherwise.Statements made
by any person, including representatives of Seller, which are inconsistent or in conflict with the terms
of this warranty shall not be binding upon Seller unless reduced to writing and approved by an officer
of Seller.
Warranty Replacement and Adjustment
All claims under warranty must be made promptly after occurrence of circumstances giving rise
thereto, and must be received within the applicable warranty period by Seller or its authorized repre-
sentative. Such claims should include the Product serial number, the date of shipment, and a full
description of the circumstances giving rise to the claim. Before any Products are returned for repair
and/or adjustment, written authorization from Seller or its authorized representative for the return and
instructions as to how and where these Products should be returned must be obtained. Any Product
returned to Seller for examination shall be prepaid via the means of transportation indicated as accept-
able by Seller.Seller reserves the right to reject any warranty claim not promptly reported and any war-
ranty claim on any item that has been altered or has been returned by non-acceptable means of
transportation.When any Product is returned for examination and inspection, or for any other reason,
Customer shall be responsible for all damage resulting from improper packing or handling, and for loss
in transit, notwithstanding any defect or non-conformity in the Product, in all cases, Seller has the sole
responsibility for determining the cause and nature of failure, and Seller's determination with regard
thereto shall be final.
If it is found that Seller’s Product has been returned without cause and is still serviceable, Customer
will be notified and the Product returned at its expense; in addition, a charge for testing and examina-
tion may be made on Products so returned.
8/15/95

i
Hazards
Operators and service personnel must be aware of all hazards associated with this equipment.They
must know how to recognize hazardous and potentially hazardous conditions, and know how to avoid
them.The consequences of unskilled, improper, or careless operation of the equipment can be seri-
ous. this product must only be operated and maintained by trained personnel. Every operator or ser-
vice person must read and thoroughly understand operation/maintenance manuals and any additional
information provided by Varian Associates. All warnings and cautions should be read carefully and
strictly observed.Consult local, state, and national agencies regarding specific requirements and reg-
ulations. Address any safety, operation, and/or maintenance questions to your nearest Varian office.
The following format is used in this manual to call attention to hazards.
WARNING
_____________
Warnings are used when failure to observe instructions or precautions
could result in injury or death to humans.
CAUTION
________
Cautions are used when failure to observe instructions could result in
significant damage to equipment and/or facilities.
NOTE
________
Notes contain information to aid the operator in obtaining the best per-
formance from the equipment.

ii
An independent agency has determined that all vacuum chambers regardless of manufacture, can
possibly become charged to lethal voltage levels, under certain conditions, if they are not grounded
with a quality, common ground with the controller of their ionization tube.
After each maintenance/service procedure and before operating the controller and vacuum system,
verify the integrity of the ground of both units; failure to do so could cost you your life!
WARNING
_____________
Check that your Ion Gauge Controller and vacuum system are sepa-
rately grounded to a common ground.
Placement of a ground wire between the vacuum chamber and the con-
troller chassis is not safe;large continuous currents could flow through it.
Personnel could be killed by high voltages (160 to 900 volts may be pre-
sent in an improperly grounded system).
Make absolutely sure that your vacuum system is grounded as shown in
the following schematic diagram;test the system ground be sure that it is
complete and capable of supporting at least 10 amperes.

iii
WARNING
_____________
This equipment contains high voltages (up to 3000 volts), high enough to
produce electric shock and cause death or serious injury.
Equipment utilizing these controls should be designed to prevent per-
sonal contact with high voltages.
Always break the primary circuit when direct access to the control unit is
required.
EMCWarnings
This is a Class A product. In a domestic environment this product may cause radio interference in
which case the user may be required to take adequate measures.
FCC
This device complies with Part 15 of the FCC rules. Operation is subject to the following two condi-
tions: (1) This device may not cause harmful interference, and (2) this device must accept any interfer-
ence received, including interference that may cause undesired operation.
NOTE
________
The equipment has been tested and found to comply with the limits for a
Class A digital device, pursuant to Part 15 of the FCC rules.These limits
are designed to provide reasonable protection against harmful interfer-
ence when the equipment is operated in a commercial environment.This
equipment generated, uses, and can radiate radio frequency energy
and, if not installed and used in accordance with the instruction manual,
may cause harmful interference to radio communications. Operation of
this equipment ina residential area is also likely to cause harmful radio
communications interference in which case the user will be required to
correct the interference at his own expense.
Installation Requirements
To maintain compliance with both the FCC Part 15 rules and the European Union’s EMI directives the
user must use a shielded cable constructed of a braided shield for the analog outputs and setpoint
wiring. Metal or metallized plastic backshells directly connected to the cable shield at the 9 pos D-Sub
connector if using serial communications.The shields of all I/O cables must be connected to ground at
the users equipment. Failure to install the equipment. Failure to install the equipment in this way may
result in the unit no longer meeting the requirements for radiated emissions and susceptibility.

Table Of Contents
Page
SAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
I INTRODUCTION AND DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1-1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1-2 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1-3 Front Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
1-4 Part Numbers and Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
1-5 Serial Communication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
II PREPARATION FOR USE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
2-1 Unpacking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
2-2 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
III OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
3-1 Keypad Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Option Select Key (All models) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Enter Key (All models) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
UP and DOWN Arrows (All models) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Stdby Key (All models) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Units Key (All models) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Cal Key (All models w/TCs or ConvecTorrs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Stpt Hyst Key (All models, with set point option) . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Emis Key (All models) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Baud Rate Key (All models) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Degas Key (BA2, BA2c, BA, UHV, UHV2c models, with degas option) . . . . . . . . . 3-2
3-2 Parameter Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
3-3 Set Point Hysteresis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
3-4 Set Point Relays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
3-5 Recorder Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6
3-6 TC and ConvecTorr Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9
3-7 Access Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9
3-8 Software Revision . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9
3-9 Display Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10
3-10 Battery Backup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10
3-11 Accessing Second Filament . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10
IV TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
4-1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
4-2 Error Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
4-3 Changing Line Fuses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
4-4 Application Footnotes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
Gas Correction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
Programming Emission mA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
Emission mA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
Sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
Programming Sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4
Appendix A Gas Correction Factor Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1

Section 1
INTRODUCTION AND DESCRIPTION
1-1 GENERAL
Varian’s senTorr Gauge Controller is a complete, half-rack vacuum gauge controller that offers contin-
uous, reliable pressure measurement from rough to high vacuum.The controller comes completely
configured from the factory to operate one of six gauge tube configurations.
UHV2c Two convectorrs and one UHV type HFIG
BA2 Two Thermocouples and one Bayard-Alpert gauge tube
BA2c Two ConvecTorrs and one Bayard-Alpert gauge tube
CC2 Two Thermocouples and one Cold Cathode gauge tube
CC2c Two ConvecTorrs and one cold cathode gauge tube
BA One Bayard-Alpert gauge tube
CC One Cold Cathode gauge tube
The senTorr Gauge Controller features one digital display per gauge tube.The displays are LED-driven
providing clear and sharp pressure readings.The front panel keypad has practical lockout features that
protect against unauthorized parameter inputs. Analog outputs and remote capabilities are located on
the back panel.The external remote input controls turnon or turnoff of high-vacuum gauge emission.
Options include set points and RS232 or RS485/422 communication ability. Resistive (I2R) degas is an
option on Bayard-Alpert models, E-beam degas on the UHV models.The set point option includes four
set points, one for each gauge tube plus an additional set point that can be assigned to any one of the
three gauge tubes.
The senTorr offers an extraordinary amount of gauging and programming capability while still remain-
ing easy to use.The operator can access all of the instrument's functions and parameters through the
front panel keypad or the optional serial link.
1-2 SPECIFICATIONS
Power Requirements 90 to 127 VAC, 50/60 HZ
208 to 250 VAC, 50/60 HZ
The senTorr is fitted with an internal switch to accommodate the desired power input.
Operating Temperature 0 to 50°C
The senTorr meets all performance specifications (unless otherwise noted) at 25°C (+5°C) at 90 per-
cent relative humidity, non-condensing.
Data Retention The senTorr will retain its parameter values, upon power down or a power
failure, for a period of four years accumulated off-time.
Size Half-rack mount, 3.5" high by 8.0" wide by 15" deep
Optional rack-mounting kits are available for mounting one or two units in a standard 19-inch rack.
Cabling The senTorr basic unit includes a 6-foot power cord and fuse set. Gauge
cabling is available separately. Standard gauge cable lengths are 10, 25,
50, 75, and 100 feet.Longer cables (up to 500 feet) are available by special
order. All cable connections are made at the rear of the unit.
1-1

Introduction and Description
Varian cannot guarantee compliance with FCC regulations for radiated emissions unless all external
wiring is shielded. (See page iii)
HFIG Gauge (BA2, BA2c, BA, UHV, UHV2c models)
Minimum pressure 1.3 x 10-7 Pa/1 x 10-9 Torr (BA)
capability 5.3 x 10-9 Pa/4 x 10-11 Torr (UHV)
Maximum pressure 1.3 x 10-1 Pa/1 x 10-3 Torr (standard BA and UHV)
capability 1.3 x 101Pa/1 x 10-1 Torr (broad-range BA)
Degas (optional) Resistive, 1 hour timeout
E-beam (UHV), 15 minute timeout
Sensitivity – Adjustable from 1330/Pa (10/Torr) standard BA default value
1.33/Pa to 1.31 x 104/Pa 1064/Pa (8/Torr) broad range BA default value
(1/Torr to 99/Torr) 3325/Pa (25/Torr) UHV default value
Emission current 4 mA (standard BA and UHV)
(Adjustable from 0.1 mA (broad range BA)
0.1 mA to 9.9 mA)
Analog output 1 V/decade
0 V for “OFF”, “- -”, and “xxE” conditions
Optional Linear Recorder Out available
Auto-on (standard) available on BA2, BA2c, and UHV2c configurations only,
set to TC1 only
Cold Cathode Gauge (CC2 CC2c, IMG, IMG2c models)
Minimum pressure 1.3 x 10-6 Pa/1 x 10-8 Torr (CC models)
capability 5.3 x 10-9 Pa/4 x 10-11 Torr (IMG models)
Maximum pressure 1.3 Pa/1 x 10-2 Torr
capability
Operating voltage –2 kV (CC models)
+3 kV (IMG models)
Sensitivity – Adjustable from (5 A/Torr) CC default value
133A/Pa to 1.31 x 104 A/Pa (2 A/Torr) IMG default value
(1 A/Torr to 99 A/Torr)
Analog output 1 V/decade
Optional Linear Recorder Out available
Auto-on (standard) available on CC2, CC2c, IMG2c configurations only, set to TC1 only
Thermocouple and Convectorr Gauge (BA2, CC2, BA2c, CC2c, UHV2c, IMG2c models)
Minimum pressure 1.3 x 10-1 Pa/1 x 10-3 Torr
capability
Maximum rated 266 Pa/2Torr (TC models)
pressure capability 1.3 x 105Pa/1000 Torr (ConvecTorr models)
1-2

Introduction and Description
Heater current 165 mA ± 10% (TC models)
Calibration 1.3 x 10-1 Pa/1 x 10-3 Torr (vacuum)
(two points) 1.0 x 105Pa/7.6 x 102Torr (atmosphere)
Auto-on threshold 1.3 x 10-1 Pa to 6.6 Pa (1 x 10-3 Torr to 5 x 10-2 Torr)
(available on TC1 only)
Analog output 1 V/decade
1 V at 1.3 x 10-1 Pa/1 x 10-3 Torr
7 V at 1.3 x 105Pa/1000 Torr
10 V for “03E” condition
Optional Linear Recorder Out available
Set Points (all models with Set Point option)
Set Points floating SPDT relays with NO, NC, and C terminals
Contact rating 3 A at 24 VDC/250 VAC, gold-flashed
Remote Input (all models)
Input 3 to 32 VDC, 500 ohms minimum to activate high-vacuum gauge
(optically-isolated and floating level-sensitive)
Options Available
Bayard-Alpert Configurations
Up to three optional plug-in printed circuit boards can be user-installed in the UHV, UHV2c, BA2,
BA2c, and BA configurations, with the following restrictions: one set point board, one degas board, and
one communications board, either RS232 or RS485/422.
Cold Cathode Configurations
Up to two optional plug-in printed circuit boards can be user-installed in the CC2, CC2c, and CC con-
figurations, with the following restrictions: one set point board and one communications board, either
RS232 or RS485/422
1-3 FRONT PANEL
The front panel display of the senTorr 7-segment, LED digits and LED annunciators.These provide con-
tinuous, crisp readings, with no directional bias.The display uses three LED colors to group information.
Green pressure data and parameter values
Yellow set point and parameter annunciators
Red operational status legends
1-3

To determine the ordering number, select the desired configuration as follows:
Basic Configurations
One Ion Gauge
BA – Bayard-Alpert (563, 564, 571, 572, 580) . . . . . L 9 1 2 0 3 0 1 X X 0 X
CC – Standard Cold Cathode (524, 525) . . . . . . . . . L 9 1 2 1 3 0 1 X X 0 X
UHV – Ultra-High-Vacuum Nude Gauge (UHV-24) . . L 9 1 1 0 3 0 1 X X 0 X
IMG – Ultra-High-Vacuum Inverted Magnetron . . . . . L 9 1 1 1 3 0 1 X X 0 X
One Ion Gauge, Two Thermocouple Gauges
BA2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L 9 1 2 0 3 0 2 X X 0 X
CC2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L 9 1 2 1 3 0 2 X X 0 X
One Ion Gauge, Two ConvecTorr Gauges
BA2c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L 9 1 2 0 3 0 3 X X 0 X
CC2c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L 9 1 2 1 3 0 3 X X 0 X
UHV2c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L 9 1 1 0 3 0 3 X X 0 X
IMG2c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L 9 1 1 1 3 0 3 X X 0 X
Setpoint Options
No Setpoints. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0
Setpoints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Degas Options
No Degas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0
Degas (BA resistive, UHV E-Beam) . . . . . . . . . . . . . 1
Communications Options
No Communications . . . . . . . . . . . . . . . . . . . . . . . . . 0
RS-232 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
RS-232 Fiber Optic. . . . . . . . . . . . . . . . . . . . . . . . . . . 2
RS-422 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
RS-485 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Introduction and Description
A single pressure display features four digits, two for the mantissa and two for the exponent.There is a
pressure readout for each gauge, with the Bayard-Alpert or Cold Cathode display labeled “IG” and the
two thermocouple or ConvecTorr displays labeled “TC1” and “TC2”, as applicable to the senTorr model.
Label pressure displayed
IG Bayard-Alpert or Cold Cathode
(depending on the model)
TC1 Thermocouple one or ConvecTorr one
TC2 Thermocouple two or ConvecTorr two
The column of red LED legends indicates the following operational states.
Degas hot filament ion gauge is degassing
Emis On ion gauge is on
Auto-On auto-on feature is programmed
mBar pressure measurements units are mBar
Torr pressure measurement units are Torr
Cal calibrating thermocouples or ConvecTorrs
Hyst programming set point hysteresis
The keypad is a sealed membrane-type, with tactile feedback.There are eleven keys, some of which
are dual function.
1-4

Introduction and Description
1-4 PART NUMBERS AND DESCRIPTIONS
1-5 SERIAL COMMUNICATION
The senTorr offers computer interface options allowing complete operation of the unit remotely via ser-
ial link.The RS232 option consists of a plug-in printed circuit board (Varian part no. L9141301) avail-
able with either a 9-pin, D-subminiature connector or fiber optic connectors (fiber-optic board, Varian
part no. L9141302). It allows complete operation of the Multi-Gauge via a computer using serial com-
munication. All of the keypad functions (except for the baud rate settings and the display output) are
accessible through the RS232 bi-directional computer link.
The RS485/422 computer interface option is available as a plug-in printed circuit board (Varian part no.
L9143301). This senTorr option provides serial communications capability as specified in EIA
(Electronic Industry Association) standard 422 and 485. Both employ differential line drivers and
receivers, and are capable of communicating to distances of 4000 feet at 19,200 baud in a multidrop
scheme, with up to 32 senTorr units.
Refer toVarian manual 6999-08-170 provided with the serial communication option for further information.
1-5

Introduction and Description
1-6

Section II
PREPARATION FOR USE
2-1 UNPACKING
Each senTorr unit is inspected and carefully packed prior to shipment. If the unit arrives damaged,
save the packing material and immediately notify the carrier. Because the packing materials are
designed specifically for this instrument, they should always be used when transporting the unit.The
shipping container is packed with the following contents.
1 senTorr Basic Unit
1 A-C line cord
1 Instruction Manual
4 rubber adhesive feet for bench top use of the senTorr
2-2 INSTALLATION
Before operating the unit, it is necessary to set it for the proper line voltage level.
1. Open the unit by removing the two screws at the top rear of the unit then pivot the cover up
and back to disengage the front lip. Lift off the cover.
2. Set the line voltage by moving line voltage selector switch S1 (Figure 2-1) to either the 115VAC
(for 110VAC or 115VAC, 50/60 Hz) or 230VAC position (for 220VAC or 240 VAC, 50/60 Hz).
3. Before replacing the top cover, check that switch S1 is correctly positioned, that all cables are
properly plugged in, and there is no loose hardware or metal parts inside the senTorr unit.
Replace the cover and secure it with the two screws.
4. Mount the unit using the desired rack-mounting kit, then attach the appropriate external
gauge and system cables.Refer to Figure 2-2 for rear panel connections and Figure 2-3 for
mounting dimensions.
2-1
NOTE
________
The unit is shipped with switch S1 (internal) set to 230 VAC.
WARNING
_____________
Before servicing the unit, check that the line cord is not plugged into a
power source. Observe all warnings and cautions printed on the cover.

2-2
Preparation for Use
Figure 2-2. Rear Panel Connections
Figure 2-1. Setting LineVoltage

2-3
Preparation for Use
Figure 2-3. Panel Cutout Dimensions
Note: Bezel Trim Kit R0130301 can be used to hide gaps between senTorr case and panel)

2-4
Preparation for Use

Section III
OPERATION
3-1 KEYPAD FUNCTIONS
Refer to Figure 3-1 for the locations of the keys and display features described in following paragraphs.
Following each key name are the senTorr models and the option (if any) to which the function applies.
Note that some of the keys may not work unless a particular option has been installed.
1. Option Select Key (All Models)
Pressing the “Option Select” key puts the senTorr into the Program mode, as indicated by the flashing
yellow annunciator. Repeated “Option Select” key presses single-steps the annunciator through the
column of set points and parameters, returning the senTorr to the Run mode after the last key press.
“Option Select” also acts as an “escape” key when pressed before the “Enter” key has been used to
store a new digit setting.
Read Section 3-2, Parameter Programming, for further information.
2. Enter Key (All Models)
Pressing the “Enter” key advances the flashing cursor through a selected Program mode, and saves
the setting when pressing “Enter” after the last digit.
3. UP and DOWN Arrows (All Models)
These keys are used to increment and decrement, respectively, digit values when entering data.
4. Stdby Key ( All Models)
Pressing the “Stdby” key will power off all of the display, the fan, and the ion gauge tube.This is a low
power shutdown;the unit will continue to provide power to the processor.
5. Units Key (All Models)
Pressing the “Units” key toggles the pressure measurement units between Torr, mBar and Pascal for
all pressure readings.The front panel legends will reflect the pressure units, with both the Torr and
mbar lamps extinguished for Pascal.
6. Cal Key (BA2, BA2c, UHV2c, CC2, CC2c, IMG2c Models)
This key is used to calibrate the vacuum and atmosphere readings for the thermocouple gauges.The
red “Cal” legend will light when calibrating the TC's or ConvecTorrs.
7. Stpt Hyst Key (All Models, with set point option)
Used in conjunction with the “Option Select” program mode to display or program the set point hys-
teresis values.The red “Hyst” legend will light to indicate that the set point pressure being displayed is
the hysteresis level (see para. 3-3).
3-1

Operation
9. Baud Rate Key (All Models)
This key is used to display and set the serial communications baud rate, parity, and the controller
address (for use in a multi-drop communication link.
After pressing “Baud Rate”, the baud rate will flash in the IG display mantissa. Use the arrow keys to
select a baud rate of 1.2 (1200), 2.4 (2400), 4.8 (4800), 9.6 (9600), or 19 (19,200).
Press “Enter” to save the current flashing value as the baud rate and to advance to the parity setting,
displayed in the IG display exponent. Use the arrow keys to select parity of O (Odd), E (Even), or “n”
(none).
Press “Enter” to save the parity setting and to advance to the controller address setting, displayed in
the IG mantissa. Use the arrow keys to select an address from 00 to 99. Once again, press “Enter” to
save the address and exit the baud rate settings.This paragraph applicable to the RS 485/422 ONLY.
The default settings are 9600 baud with no parity and an address of 00.
10. Degas Key (BA, UHV Models, with degas option)
Can only activate if the pressure at the Bayard-Alpert ion gauge is less than 10-3 Pa/10-5 Torr. Pressing
the “Degas” key will illuminate the hidden degas legend to reflect the state of the degas. Pressing the
Degas key again will turn the degas function off.After engagement, the degas will automatically turn
off after approximately 1 hour, for I2R degas, 15 min for E-beam.The degas option must be installed to
operate this function; if the user does not purchase the degas option, then this key has no effect.
3-2
Figure 3-1. Front Panel, senTorr Gauge Controller
8. Emis Key (All Models)
Pressing “Emis” turns the high vacuum gauge on or off.The hidden “Emis On” legend will light to reflect
the on state of the ion emissions.The high vacuum gauge emissions will come on only if the appropri-
ate vacuum has been achieved.
8. Emis Key (BA/UHV dual filament models)
Pressing the “Enter” key before pressing “Emis” uses the second filament.

Operation
3-2 PARAMETER PROGRAMMING
The set point and ion gauge parameters listed in a column on the front panel display (see Figure 3-1)
can be viewed or programmed by putting the senTorr into the Program mode.To the left of each para-
meter is a single yellow LED.
If the yellow LED is flashing, that parameter is selected to the Program mode and its value is displayed
in the corresponding gauge readout.
If the yellow LED is lit solidly, that menu item is active, meaning that the set point is energized or the
ion gauge parameter has been changed from its default setting.
Enter the Program mode by pressing the “Option Select” key.The first available parameter, beginning
from the top of the column and depending on the senTorr models and options installed, will flash in the
appropriate gauge display. Repeated “Option Select” key presses will advance through the parameters,
returning the unit to the Run mode after the last key press.
When the desired parameter has been selected, the up and down arrow keys can be used to set a
new value to the flashing digit.The “Enter” key will advance the flashing through the digits, saving the
new value after the last digit has been set.
3-3
NOTE
________
If the yellow LED is left flashing in the Program mode unattended for
more than 5 seconds, the default will automatically return the annuncia-
tor to the Run mode.
A changed value will not be saved unless it has been “Entered” through
all of its digits.The “Option Select” key can be used to “escape” from sav-
ing a changed value prior to “Enter”ing the last digit.
After the value has been saved, the whole setting will flash. Press “Enter” to re-program the value, or
“Option Select” to advance to the next parameter.The senTorr will exit the Program mode if no keys
are pressed for about 8 seconds.
To disable a set point, set its mantissa to “0.0”.
IG Setpt (All Models with Set Point option)
The ion gauge set point can be set to energize when the ion gauge pressure drops below the IG Setpt
threshold setting. It will de-energize when the ion gauge pressure goes above the IG Setpt hysteresis
setting (refer to Para. 3-3, Set Point Hysteresis).The IG Setpt pressure will flash in the IG display. Use
the up and down arrow keys and the “Enter” key to set the digit values and advance through the digits.
TC1 Setpt (All models with Set Point option)
The TC1 set point can be set to energize when TC1 reads less than the TC1 Setpt threshold setting.
It will de-energize when the TC1 pressure goes above the TC1 Setpt hysteresis setting (refer to Para.
3-3, Set Point Hysteresis).The TC1 Setpt pressure wll be displayed in theTC1 readout.