Instrutech Super Bee CVM201 User manual

p/n 000312-120
InstruTech®, Inc.
CVM201 Convection Vacuum Gauge Module
The Super Bee™
User Manual
InstruTech, Inc.
1475 S. Fordham St.
Longmont, CO 80503
USA
Phone: [phone]
Fax: [phone]
E-mail [email protected]
www.instrutechinc.com

p/n 000312-120
Copyright © 2012 by InstruTech, Inc.
All rights reserved. No part of this work may be reproduced or transmitted in any form or by any means, electronic or mechanical,
including photocopying and recording, or by any information storage or retrieval system, except as may be expressly permitted in
writing by InstruTech, Inc.
Printed in the United States of America
Swagelok®, VCO®, VCR®are registered trademarks of Swagelok Co., Solon, OH
Convectron®, Mini-Convectron®, and Granville-Phillips®are registered trademarks of Brooks Automation, Inc. Chelmsford, MA
Teflon®is a registered trademark of E. I. du Pont de Nemours and Company, Wilmington, DE
Conflat®is a registered trademark of Varian, Inc. / Agilent Technologies, Lexington, MA

Instruction Manual CVM201 Super Bee
InstruTech, Inc. Page 1
Table of Contents
1 Introduction / General Information......................................................................................................3
1.1 Description ....................................................................................................................................3
1.2 Specifications ................................................................................................................................3
1.3 Dimensions....................................................................................................................................4
1.4 Part Numbers ................................................................................................................................4
2 Important Safety Information...............................................................................................................6
2.1 Safety Precautions - General.........................................................................................................6
2.2 Safety Precautions - Service and operation..................................................................................7
2.3 Electrical Conditions......................................................................................................................7
2.3.1 Proper Equipment Grounding ...............................................................................................7
2.3.2 Electrical Interface and Control .............................................................................................7
2.4 Overpressure and use with hazardous gases ...............................................................................8
2.5 Gases other than Nitrogen / air ....................................................................................................8
3 Installation ............................................................................................................................................9
3.1 Mechanical Installation.................................................................................................................9
3.2 Electrical Installation...................................................................................................................10
3.2.1 Grounding ............................................................................................................................10
3.2.2 Electrical Connections..........................................................................................................10
4 Setup and Operation...........................................................................................................................11
4.1 User Interface Basics...................................................................................................................11
4.2 Programming...............................................................................................................................11
4.3 Return to Factory Default Settings .............................................................................................13
5 Using the gauge with different gases .................................................................................................14
6 Display.................................................................................................................................................16
6.1 Display - Torr / mTorr..................................................................................................................16
6.2 Display - mbar .............................................................................................................................17

Instruction Manual CVM201 Super Bee
InstruTech, Inc. Page 2
7 Analog Output.....................................................................................................................................18
7.1 Non-Linear Analog Output - Torr / mTorr...................................................................................19
7.2 Non-Linear Analog Output - mbar ..............................................................................................20
7.3 Log-Linear Analog Output - Torr .................................................................................................21
7.4 Log-Linear Analog Output - mbar ...............................................................................................23
8 RS485 / RS232 serial communications................................................................................................25
8.1 Device Specific Serial Communication Info.................................................................................25
8.2 RS485 / RS232 Command Protocol Summary ............................................................................26
9 Service .................................................................................................................................................27
9.1 Calibration...................................................................................................................................27
9.2 Maintenance ...............................................................................................................................27
9.3 Troubleshooting..........................................................................................................................27
9.4 Contamination ............................................................................................................................28
9.5 Module and sensor replacement................................................................................................29
10 Factory Service and Support...........................................................................................................30
11 Warranty.........................................................................................................................................30

Instruction Manual CVM201 Super Bee
InstruTech, Inc. Page 3
1 Introduction / General Information
1.1 Description
Thermal conductivity gauges measure pressure indirectly by sensing the loss of heat from a sensor to the
surrounding gases. The higher the pressure of the surrounding gas, the more heat is conducted away from the
sensor. Pirani thermal conductivity gauges maintain a sensor (usually a wire) at some constant temperature,
and measure the current or power required to maintain that temperature. A standard Pirani gauge has a useful
measuring range of about 10-4 Torr to 10 Torr. By taking advantage of convection currents that are generated
above 1 Torr, convection-enhanced Pirani gauges increase the measuring range to just above atmosphere.
The InstruTech® CVM201 Super Bee™module provides the basic signal conditioning required to turn a
convection vacuum gauge into a complete measuring instrument. The module provides linear, non-linear or log-
linear analog outputs, two setpoint relays and RS232/485 serial communications. In addition, a built-in display
provides a convenient user interface for setup and operation of the vacuum gauge.
1.2 Specifications
measurement range (signal)
1.0 x 10-4 to 1000 Torr / 1.3 x 10-4 to 1333 mbar / 1.3 x 10-2 Pa to 133 kPa
accuracy - N2 (typical)
1.0 x 10-4 to 1.0 x 10-3 Torr; 0.1 mTorr resolution
1.0 x 10-3 to 400 Torr; ± 10% of reading
400 to 1,000 Torr; ±2.5% of reading
repeatability - (typical)
± 2% of reading
display
bright OLED, 4 digits, user-selectable Torr, mbar, or Pa,
(4 digits from 1100 Torr to 1000 Torr), (3 digits from 999 Torr to 10.0 mTorr),
(2 digits from 9.9 mTorr to 1.0 mTorr ), (1 digit from 0.9 mTorr to 0.1 mTorr)
materials exposed to gases
gold-plated tungsten, 304 & 316 stainless steel, glass, nickel, Teflon®
internal volume
1.589 in3(26 cm3)
internal surface area
9.25 in2(59.7 cm2)
weight
12 oz. (340 g)
housing (electronics)
aluminum extrusion
operating temperature
0 to +40 oC
storage temperature
-40 to +70 oC
bakeout temperature
150 oC max (gauge only - electronics removed)
humidity
0 to 95% relative humidity, non-condensing
altitude
operating; 6,560 ft. (2,000 m) max storage; 41,000 ft. (12,500 m) max
mounting position
horizontal recommended
analog outputs
1) log-linear 1 to 8 Vdc, 1 V/decade or non-linear S-curve 0.375 to 5.659 Vdc, and
2) linear 0 to 10 Vdc
serial communications
RS485 / RS232 - ASCII protocol
input power
11 to 30 Vdc, 2 W, protected against power reversal, transients, and over-voltages
setpoint relays
two, single-pole double-throw relays (SPDT), 1 A at 30 Vdc resistive, or ac non-inductive
connectors
9-pin D-sub male and 15-pin high-density D-sub male
RF/EMI protection
CE compliant
environmental
RoHS compliant

Instruction Manual CVM201 Super Bee
InstruTech, Inc. Page 4
1.3 Dimensions
1.4 Part Numbers
CVM201 Fittings / Flanges Part Number
Combination 1/8 in. NPT male - 1/2 in. tube
(use 1/8 in. NPT male or 1/2 in. O.D. O-ring compression)
CVM201GAA
NW16KF
CVM201GBA
NW25KF
CVM201GCA
NW40KF
CVM201GDA
1 1/3 in. Mini-CF / NW16CF Mini-Conflat®
CVM201GEA
2 3/4 in. CF / NW35CF Conflat®
CVM201GFA
1/4 in. Cajon® 4VCR® female
CVM201GGA
1/2 in. Cajon® 8VCR® female
CVM201GHA
fitting
dimension A
1/8 in. NPT male - 1/2 in. tube
0.86 in. (21.8 mm)
NW16KF
1.16 in. (29.5 mm)
NW25KF
1.16 in. (29.5 mm)
NW40KF
1.16 in. (29.5 mm)
1 1/3 in. Mini-Conflat®
1.34 in. (34.0 mm)
2 3/4 in. Conflat®
1.34 in. (34.0 mm)
1/4 in. Cajon®4VCR®
1.72 in. (43.7 mm)
1/2 in. Cajon®8VCR®
1.61 in. (40.9 mm)

Instruction Manual CVM201 Super Bee
InstruTech, Inc. Page 5
Part Numbers Continued - P/N
Optional PS401 Wall Mount AC-DC
Power Supply
with North American AC Plug
PS401-A
with Universal European AC Plug
PS401-EU
with UK AC Plug
PS401-UK
with China AC Plug
PS401-C
with Australian AC Plug
PS401-SP
Optional PS401 For Use With User
Supplied AC Power Cord
This variation of the PS401 power supply
may be used when an AC plug that is not
listed above is required. The conventional
IEC60320 AC power entry receptacle allows
use with any user supplied AC mains power
cord set available worldwide.
PS401-UX

Instruction Manual CVM201 Super Bee
InstruTech, Inc. Page 6
2 Important Safety Information
InstruTech has designed and tested this product to provide safe and reliable service, provided it is installed and
operated within the strict safety guidelines provided in this manual.Please read and follow all warnings and
instructions.
To avoid serious injury or death, follow the safety information in this document. Failure to comply with these
safety procedures could result in serious bodily harm, including death, and or property damage.
Failure to comply with these warnings violates the safety standards of installation and intended use of this
instrument. InstruTech, Inc. disclaims all liability for the customer’s failure to comply with these instructions.
Although every attempt has been made to consider most possible installations, InstruTech cannot anticipate
every contingency that arises from various installations, operation, or maintenance of the module. If you have
any questions about the safe installation and use of this product, please contact InstruTech.
2.1 Safety Precautions - General
The product should never be operated with the enclosure removed.
WARNING! There are no operator serviceable parts or adjustments inside the product enclosure.
However, the sensor inside the product enclosure is replaceable. Refer servicing to service trained personnel.
Do not modify this product or substitute any parts without authorization of qualified InstruTech service trained
personnel. Return the product to an InstruTech qualified service and repair center to ensure that all safety
features are maintained. Do not use this product if unauthorized modifications have been made.
WARNING! Source power must be removed from the product prior to performing any servicing.
After servicing this product, ensure that all safety checks are made by a qualified service person. When
replacement parts are required, ensure that the parts are specified by InstruTech, Inc. Substitutions of non-
qualified parts may result in fire, electric shock or other hazards. Use of unauthorized parts or modifications
made to this product will void the warranty.
To reduce the risk of fire or electric shock, do not expose this product to rain or moisture. These products are
not waterproof and careful attention must be paid to not spill any type of liquid onto these products. Do not
use these products if they have been damaged. Immediately contact InstruTech, Inc. to arrange return of the
product if it is damaged.
Due to the possibility of corrosion when used in certain environmental conditions, it is possible that the
product’s safety could be compromised over time. It is important that the product be periodically inspected for
sound electrical connections and equipment grounding. Do not use if the equipment grounding or electrical
insulation has been compromised.
WARNING
WARNING
WARNING

Instruction Manual CVM201 Super Bee
InstruTech, Inc. Page 7
2.2 Safety Precautions - Service and operation
Ensure that the vacuum port on which the CVM201 vacuum gauge is mounted is electrically grounded.
Use an appropriate power source of 11 to 30 Vdc, 2 W.
Turn off power to the unit before attempting to service the module.
Turn off power to the unit if a cable or plug is damaged or the product is not operating normally according to
this instruction manual. Contact qualified InstruTech service personnel for any service or troubleshooting
condition that may not be covered by this instruction manual.
It is important that the product be periodically inspected for sound electrical connections and equipment
grounding. Do not use if the equipment grounding or electrical insulation has been compromised.
Do not use if the unit has been dropped or the enclosure has been damaged. Contact InstruTech for return
authorization and instructions for returning the product to InstruTech for evaluation.
2.3 Electrical Conditions
WARNING! When high voltage is present in any vacuum system, a life threatening electrical shock hazard
may exist unless all exposed electrical conductors are maintained at earth ground potential. This applies to all
products that come in contact with the gas contained in vacuum chambers. An electrical discharge within a
gaseous environment may couple dangerous high voltage directly to any ungrounded conductor of electricity. A
person could be seriously injured or killed by coming in contact with an exposed, ungrounded electrical
conductor at high voltage potential. This condition applies to all products that may come in contact with the gas
inside the vacuum chamber (vacuum/pressure containment vessel).
2.3.1 Proper Equipment Grounding
WARNING! Hazardous voltages that could seriously injure or cause death are present in many vacuum
processes. Verify that the vacuum port on which the CVM201 vacuum gauge module is mounted is electrically
grounded. Consult a qualified Electrician if you are in doubt about your equipment grounding. Proper
grounding of your equipment is essential for safety as well as intended operation of the equipment. The
CVM201 module vacuum gauge must be connected directly to a good quality earth ground. Use a ground lug on
the CVM201 gauge vacuum connection / flange if necessary.
WARNING! In order to protect personnel from electric shock and bodily harm, shield all conductors
which are subject to potential high voltage electrical discharges in or around the vacuum system.
2.3.2 Electrical Interface and Control
It is the user’s responsibility to ensure that the electrical signals from this product and any connections made to
external devices, for example, relays and solenoids, are used in a safe manner. Always double check the system
set-up before using any signals to automate your process. Perform a hazardous operation analysis of your

Instruction Manual CVM201 Super Bee
InstruTech, Inc. Page 8
system design and ensure safeguards and personnel safety measures are taken to prevent injury and property
damage.
2.4 Overpressure and use with hazardous gases
WARNING! Install suitable protective devices that will limit the level of pressure inside your vacuum
chamber to less than what the vacuum chamber system components are capable of withstanding. InstruTech
gauges should not be used at pressures exceeding 1000 Torr absolute pressure.
In cases where an equipment failure could cause a hazardous condition, always implement fail-safe system
operation. For example, use a pressure relief device in an automatic backfill operation where a malfunction
could result in high internal pressures if the pressure relief device was not installed on the chamber.
The CVM201 vacuum gauge module is not intended for use at pressures above 20 psia (1000 torr); DO NOT
exceed 35 psig (< 2 ½ bars) pressure inside the sensor. If your chamber goes to higher pressures, you should
install an isolation valve or pressure relief device to protect the gauge tube from overpressure conditions. With
some fittings, actual safe overpressure conditions may be lower; for example, a quick-connect, O-ring
compression fitting may forcibly release the gauge tube from the vacuum chamber fitting with only a few psi
over local uncorrected barometric (atmospheric) pressure.
CAUTION! If the internal pressure of a vacuum gauge device is allowed to increase above local
uncorrected barometric pressure (atmospheric pressure side), vacuum fittings may release and possible
overpressure conditions may cause leaks that would allow the gas inside the gauge tube to release into the
atmosphere of the surrounding environment. Toxic, pyrophoric and flammable gases are examples of
hazardous gases that if allowed to leak out of the vacuum/pressure containment vessel into the atmospheric
environment, could cause bodily injury and possible damage to equipment. Never expose the gauge tube
internal volume to pressure above local atmospheric pressure when using hazardous gases.
2.5 Gases other than Nitrogen / air
WARNING! Do not attempt to use with gases other than nitrogen (N2) or air without referring to correction
factor data tables.
InstruTech gauges and modules are calibrated for direct readout of nitrogen or air. Do not attempt to use with
other gases such as argon (Ar) or carbon dioxide (CO2) unless accurate conversion data for N2 to other gas is
properly used. Refer to sections titled “Using the gauge with different gases”, “Display” and “Analog Output” for
a more complete discussion.
WARNING! Do not use this device in an explosive atmosphere or in the presence of flammable gases,
vapors or fumes. Do not use this device to measure the pressure of explosive or combustible gases or gas
mixtures. The sensor wire in the gauge normally operates at 125 oC, but if malfunction should occur, the wire
temperature could exceed the ignition temperature of certain combustible gases and gas mixture. This could
cause an explosion which could result in serious injury or death.

Instruction Manual CVM201 Super Bee
InstruTech, Inc. Page 9
3 Installation
3.1 Mechanical Installation
Mount the CVM201 as close as possible to the pressure
you want to measure. Long or restricted, small
diameter tubing will create a pressure difference
between your process chamber and the gauge. This
may cause a delay in response to pressure changes.
Mounting the CVM201 too close to a gas source inlet
may also cause measurement and control instability.
Do not mount the CVM201 near a source of heating or
cooling, such as heaters or air conditioning vents.
Mount the CVM201 with its main (long) axis horizontal (see diagram at right). The CVM201 is calibrated in this
orientation. Pressure reading errors may occur above 1 Torr if the unit is not mounted horizontally. Below 1
Torr, mounting position has little to no effect.
Mount the CVM201 with port down, if possible, to help minimize the effect of any particles or condensation
from collecting in the gauge.
Do not mount the CVM201 where it will be subjected to excessive vibration. Vibrations may cause unstable
readings, measurement errors and possible mechanical stress to components in the CVM201.
Flanges/ Fittings - follow the manufacturer's recommendations and note the following:
- NPT fittings: When connecting the device using a NPT fitting, apply a thread sealant compound or wrap the
threaded portion of the tubing with one-and-a-half to two wraps of pipe thread seal tape such as PTFE (Teflon®)
tape and hand tighten the gauge into the gauge port. Do not use a wrench or other tool which may damage the
gauge.
Mount
CVM with
this axis
horizontal

Instruction Manual CVM201 Super Bee
InstruTech, Inc. Page 10
3.2 Electrical Installation
3.2.1 Grounding
Be sure the vacuum gauge and the rest of your vacuum system are properly grounded to protect personnel
from shock and injury. Be aware that some vacuum fittings, especially those with O-rings when not used with
metal clamps, may not produce a good electrical connection between the gauge and the chamber it is
connected to.
3.2.2 Electrical Connections
A good recommended practice is to remove power from any cable prior to connecting or disconnecting it.
The InstruTech CVM201 will directly replace Granville-Phillips® Mini-Convectron® modules that have a 9-pin
D-sub connector (DE-9P) or 15-pin D-sub connector (DE-15P), and you can use your existing cables and
electronics. For new installations, fabricate a cable to connect to the signals/functions you want to use. Signals
and pin assignments are described below:
Connector and Pinout
PIN NUMBER
PIN DESCRIPTION
1
Relay 1 Normally Open
2
Relay 1 Normally Closed
3
Power Input (11-30 Vdc)
4
Power Ground
5
Analog Output 1 (Log-Linear 1-8V, or Non-linear Granville-Phillips® Mini-Convectron ®compatible)
6
Relay 1 Common
7
Relay Disable (Disables both Relays when connected to pin 4 - Ground)
8
Analog Ground
9
Analog Output 2 (Programmable Linear 0-10 V)
PIN NUMBER
PIN DESCRIPTION
1
RS485 DATA B (+) Input/output
2
RS485 DATA A (-) Input/output
3
Power Input (11-30 Vdc)
4
Power Ground
5
Analog Output 1 (Log-Linear 1-8 V, or Non-linear Granville-Phillips® Mini-Convectron ®compatible)
6
Analog Ground
7
RS232 TX
8
RS232 RX
9
Relay Disable (Disables both Relays when connected to pin 4 - Ground)
10
Relay 1 Normally Open
11
Relay 2 Normally Open
12
Relay 2 Common
13
Relay 2 Normally Closed
14
Relay 1 Normally Closed
15
Relay 1 Common

Instruction Manual CVM201 Super Bee
InstruTech, Inc. Page 11
4 Setup and Operation
4.1 User Interface Basics
The user interface is designed for easy operation and a
natural progression of setup parameters. This section gives a
brief explanation of operation for added clarity.
There are four soft-keys located on the front panel, two on
each side of the display. These keys are used to select and
program the various functions available. During programming
Programming soft-keys
of the CVM201, the display will identify what function each
key represents.
To begin programming, press any one of the four keys. The display will indicate a choice of functions. Press the
key indicated by the function on the display to continue with the programming of the parameter desired. After
setting the various parameters, press the SAVE key to save the new setting and return to the main screen. To
continue setting additional parameters, scroll forward with the MORE key until you reach the desired
parameter.
4.2 Programming
SET VAC
When operating in units of either mbars (mbar) or pascals (Pa), you must perform SET ATM
before setting the vacuum reading (SET VAC). See SET ATM below. Failure to do so will result in improper
operation of the gauge. If you change units of measure or reset to factory defaults, then this same procedure
must be followed again if the units of measure are being set to either mbar or Pa.
1. To properly set the vacuum reading (“zero” point), with the CVM201 installed on your vacuum system,
the gauge should be evacuated to a pressure below 1 x 10-4 Torr.
2. Go to the SET VAC screen. When the vacuum system pressure is below 1 x 10-4 Torr, press the PRESS TO
SET VAC key. The zero point (displayed pressure reading with gauge exposed to vacuum) is now set.
UNITS [Factory default = TORR]
This should be the first parameter that is set. This will be the units-of-measure (TORR, mBAR, PASCAl) that are
used for all other settings. If your CVM201 has been previously configured and relay setpoints and linear analog
output pressure settings have been programmed, changing units-of-measure will return the relays setpoints and
the linear analog output pressure settings to factory default setting values in TORR. In this case, you must
reprogram the relay setpoints and linear analog output pressure settings in the newly programmed units-of-
measure.
NOTICE

Instruction Manual CVM201 Super Bee
InstruTech, Inc. Page 12
SET ATM
1. To set the atmospheric pressure reading (also known as the “span” adjustment), flow nitrogen gas or air
into your closed vacuum chamber to allow the pressure to rise to a known value above 400 Torr.
Alternatively, if your local uncorrected barometric pressure (air) is known, simply vent your vacuum
system chamber to expose the gauge to the local atmospheric pressure.
2. Go to the SET ATM screen. When the desired pressure is stable, adjust the displayed pressure reading
on the CVM201 to the known value using the INCR (increase) or DECR (decrease) keys. Press the SAVE
key to save the new atmospheric (span) pressure value.
It is good practice to perform the sequence of checking and adjusting span (ATM) then zero (VAC) and
then, finally re-checking the span setting to ensure that the circuitry is properly balanced for use in
measuring pressure throughout the intended measurement range.
SP1 ON and SP2 ON [Factory default = 100 mTORR]
These setpoints correspond to the pressures at which the relays will turn on (energize). The relays will turn on
when the pressure is below the programmed pressure value. If you are unable to increase the values of SP1 ON
or SP2 ON , you must first go to SP1 OFF or SP2 OFF and increase those values to a number higher than the
values of SP1 ON or SP2 ON you are trying to set.
SP1 OFF and SP2 OFF [Factory default = 200 mTORR]
These setpoints correspond to the pressures at which the relays will turn off (de-energize). The relays will turn
off when the pressure is above the programmed pressure value. If you are unable to decrease the values of SP1
OFF or SP2 OFF, you must first go to SP1 ON or SP2 ON and decrease those values to a number lower than the
values of SP1 OFF or SP2 OFF you are trying to set.
RS485 ADDR [Factory default = 1]
This is the lower nibble of the one byte RS485 device address. Assuming the address offset (RS485 OFFSET) is
equal to 0, setting the ADDR to a 5 will make the address be 0x05 in hexadecimal. A 15 will set the ADDR to
0x0F in hexadecimal. Note that the address (ADDR) must be used even when sending RS232 commands
RS485 OFFSET [Factory default = 0]
This is the upper nibble of the one byte RS485 address. Assuming the address (ADDR) is 0, setting the address
offset (RS485 OFFSET) to a 5 will make the address be 0x50 hexadecimal. Setting the address offset to 15 will
make the device address be 0xF0 hexadecimal.
┌-----------------------------BINARY ADDRESS-----------------------------┐
ADDRESS
DECIMAL
┌-------------------------------------ONE BYTE-----------------------------------┐
ADDRESS
HEXADECIMAL
(BINARY)
ADDR OFFSET
┌Upper nibble┐
ADDR
┌Lower nibble┐
1
0 0 0 0
0 0 0 1
01
5
0 0 0 0
0 1 0 1
05
15
0 0 0 0
1 1 1 1
0F
16
0 0 0 1
0 0 0 0
F0

Instruction Manual CVM201 Super Bee
InstruTech, Inc. Page 13
BAUD [Factory default = 19,200]
This sets the baud rate for the RS485 and the RS232 serial communications. The baud rate can be set to various
values through the serial interface or via the front panel soft-keys. The parity can only be changed through the
serial interface command set. When this occurs, the current setting will be shown in the list of choices and can
be re-selected if changed.
SET LINEAR [Factory default = 0.01 VOLTS to 10 VOLTS corresponding to 1 mTORR to 1 TORR]
This will take the user to four different screens to setup the linear analog output (See Analog Output section).
a) Set the minimum pressure
b) Set the minimum voltage corresponding to the minimum pressure
c) Set the maximum pressure
d) Set the maximum voltage corresponding to the maximum pressure
The linear output voltage can be any value between 0.01 Vdc and 10 Vdc corresponding to pressures between
1 mTorr and 1000 Torr.
INFO
This screen shows the unit software version.
ANALOG TYPE [Factory default = NONLIN]
Select “NONLIN” for non-linear (S-Curve) or “LOG” for log-linear analog output (See Analog Output section).
4.3 Return to Factory Default Settings
You can reset all values to the original factory default settings by simultaneously pressing the upper left and
upper right soft-keys. The user will then be prompted “Set Factory Defaults?” Choose Yes or No.

Instruction Manual CVM201 Super Bee
InstruTech, Inc. Page 14
5 Using the gauge with different gases
A thermal conductivity gauge senses heat loss which depends on the thermal conductivity of the gas surrounding the
sensor. Since different gases, and mixtures, have different thermal conductivities, the indicated pressure readings and
outputs will also be different. InstruTech convection gauges (and most other thermal conductivity gauges) are calibrated
using nitrogen (N2). When a gas other than N2/ air is used, correction must be made for the difference in thermal
conductivity between nitrogen (N2) and the gas in use. The charts and tables on the following pages indicate how different
gases affect the display and output from an InstruTech convection gauge.
WARNING! Using a thermal conductivity gauge with gases other than that for which it is calibrated could result in
death or serious injury. Be sure to use gas correction data in this manual when measuring pressures of gases other than
N2 / air.
For N2the calibration shows excellent agreement between indicated and true pressure throughout the range from 10-4 to
1000 Torr. At pressures below 1 Torr, the calibration curves for the different gases are similar. The difference in readings
at these low pressures is a constant, a function of the difference between thermal conductivities of the gases.
At pressures above 1 Torr, indicated pressure readings may diverge significantly. At these higher pressures convection
currents in the gauge become the predominant cause of heat loss from the sensor and calibration depends on gauge tube
geometry and mounting position as well as gas properties.
Generally, air and N2are considered the same with respect to thermal conductivity, but even N2 and air will exhibit slight
differences in readings at higher pressures. For example, when venting a system to atmosphere using N2, you may see
readings change by 30 to 40 Torr after the chamber is opened and air gradually displaces the N2in the gauge. For most
other gases the effect is much more significant and may result in a hazardous condition as described below.
Other considerations when using gases other than N2/ air
Flammable or explosive gases
WARNING! InstruTech convection gauges are neither intrinsically safe nor explosion proof and are not intended for
use in the presence of flammable or explosive gases or vapors.
Under normal conditions the voltages and currents in InstruTech convection gauges are too low to cause ignition of
flammable gases. However, under certain failure conditions, sufficient energy could be generated to cause flammable
vapors or gases to ignite or explode. Thermal conductivity gauges like the InstruTech convection gauges are not
recommended for use with flammable or explosive gases.
Moisture / water vapor
In some processes (lyophilization, for example) the gas composition may not change significantly, except for moisture
content. Water vapor can significantly change the response of a thermal gauge and correction should be made, as you
would for any other gas.
Other contaminants
If your gases condense, coat, or corrode the sensor, the gauge calibration and response to different gases will change.
Generally, if the gauge can be "calibrated" ("zero" and "span" settings), these changes are small enough to be ignored. If
you can’t set zero and span, the gauge should be replaced or return to factory for evaluation and possible cleaning.

Instruction Manual CVM201 Super Bee
InstruTech, Inc. Page 15
Convection Vacuum Gauge
Indicated vs. True Total Pressure
Test Gases - N2, Ar, He
0.0001
0.001
0.01
0.1
1
10
100
1000
0.0001 0.001 0.01 0.1 1 10 100 1000
Indicated Pressure (Torr)
(convection gauge)
True Total Pressure (Torr)
(capacitance manometer)
CVG N2 Convectron N2 CVG Ar Convectron Ar Convectron He CVG He
Ar
N2
He
Gas Correction Chart
The Y- axis of the above chart is actual pressure as measured by a capacitance manometer, a diaphragm gauge
that measures true total pressure independent of gas composition. The X-axis is the pressure reading indicated
by the convection gauge under test. This chart shows readings for an InstruTech convection gauge (CVG) and
Granville-Phillips® Convectron® gauge to illustrate that the difference in the response for both of these types of
gauges is virtually indistinguishable.
CAUTION! Do not assume this data applies to other convection gauges which may or may not be the same.
Refer to the table in section 6.1 and note the following examples:
Ex A: If the gas is nitrogen (N2), when the true total pressure is 500 Torr, the gauge will read 500 Torr.
Ex B: If the gas is argon (Ar), when the true pressure is 100 Torr, the gauge will read about 9 Torr.
If you are backfilling your vacuum system with Ar, when your system reaches a pressure of 760 Torr
true pressure your gauge will be reading about 23 Torr. Continuing to backfill your system, attempting to
increase the reading up to 760 Torr, you will over pressurize your chamber which may present a hazard.
Ex C: If the gas is helium (He), the gauge will read 999 Torr when pressure reaches about 10 Torr true pressure
and opening the chamber to atmosphere prematurely may present other hazards for both people and product.
CAUTION! What these examples illustrate is that using gases other than nitrogen (N2) without using accurate
gas conversion data and other proper precautions could result in injury to personnel and/or damage to
equipment.
Suggested precautions when using gases other than nitrogen (N2):
Install a pressure relief valve or burst disk on your chamber, to protect it from overpressure. Post a warning
label on your gauge readout that states "Do Not Exceed ____ Torr Indicated Pressure" (fill in the blank for
maximum indicated pressure for the gas you use) so that an operator using the gauge will not exceed a safe
pressure.

Instruction Manual CVM201 Super Bee
InstruTech, Inc. Page 16
6 Display
6.1 Display - Torr / mTorr
The table below shows the displayed readings at various pressures for selected gases when engineering units
selected is in Torr/mTorr.
Displayed Pressure Readings vs. True Pressure for selected gases
Pressures shown in bold italic font in the shaded areas are in mTorr.
Pressures shown in normal font and in non-shaded areas are in Torr.
N2Ar He O2CO2Kr Freon12 Freon22 D2Ne CH4
0 mTorr 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
0.1 mTorr 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1
0.2 mTorr 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2
0.5 mTorr 0.5 0.5 0.5 0.5 0.5 0.3 0.5 0.5 0.5 0.5 0.5
1 mTorr 1.0 0.7 0.8 1.0 1.1 0.4 1.5 1.5 1.3 0.7 1.7
2 mTorr 2.0 1.4 1.6 2.0 2.3 1.0 3.1 3.1 2.4 1.5 3.3
5 mTorr 5.0 3.3 4.0 5.0 4.4 2.3 7.6 7.0 6.0 3.5 7.7
10 mTorr 10.0 6.6 8.1 9.7 11.0 4.8 14.7 13.5 12.1 7.1 15.3
20 mTorr 20.0 13.1 16.1 19.8 22.2 9.5 29.9 27.2 24.3 14.1 30.4
50 mTorr 50.0 32.4 40.5 49.2 54.9 23.5 72.5 69.0 60.0 34.8 77.2
100 mTorr 100 64.3 82.0 97.2 107 46.8 143 136 121 70.0 159
200 mTorr 200 126 165 194 210 91.1 275 262 250 141 315
500 mTorr 500 312 435 486 489 217 611 594 687 359 781
1 Torr 1.00 600 940 970 950 400 1.05 1.04 1.55 745 1.60
2 Torr 2.00 1.14 2.22 1.94 1.71 700 1.62 1.66 4.13 1.59 3.33
5 Torr 5.00 2.45 13.5 4.98 3.34 1.28 2.45 2.62 246 5.24 7.53
10 Torr 10.0 4.00 OP 10.3 4.97 1.78 2.96 3.39 OP 21.5 27.9
20 Torr 20.0 5.80 OP 22.3 6.59 2.29 3.32 3.72 OP 584 355
50 Torr 50.0 7.85 OP 77.6 8.22 2.57 3.79 4.14 OP OP 842
100 Torr 100 8.83 OP 209 9.25 2.74 4.68 4.91 OP OP OP
200 Torr 200 9.79 OP 295 12.3 3.32 5.99 6.42 OP OP OP
300 Torr 300 11.3 OP 380 16.9 3.59 6.89 7.52 OP OP OP
400 Torr 400 13.5 OP 485 22.4 3.94 7.63 8.42 OP OP OP
500 Torr 500 16.1 OP 604 28.7 4.21 8.28 9.21 OP OP OP
600 Torr 600 18.8 OP 730 36.4 4.44 8.86 9.95 OP OP OP
700 Torr 700 21.8 OP 859 46.1 4.65 9.42 10.7 OP OP OP
760 Torr 760 23.7 OP 941 53.9 4.75 9.76 11.1 OP OP OP
800 Torr 800 25.1 OP 997 59.4 4.84 9.95 11.4 OP OP OP
900 Torr 900 28.5 OP OP 79.5 4.99 10.5 12.0 OP OP OP
1000 Torr 1000 32.5 OP OP 111 5.08 11.1 12.7 OP OP OP
Notes:
1) OP = overpressure indication: display will read over pressure
2) Display auto-ranges between Torr and mTorr at 1 Torr
True Total
Pressure
Examples:
1) Gas used is nitrogen (N2). Display shows pressure measurement of 10 Torr. True pressure of nitrogen is 10 Torr.
2) Gas used is argon (Ar). Display shows pressure measurement of 600 mTorr. True pressure of argon is
1 Torr.
3) Gas used is oxygen (O2). Display shows pressure measurement of 486 mTorr. True pressure of oxygen is 500 mTorr.

Instruction Manual CVM201 Super Bee
InstruTech, Inc. Page 17
6.2 Display - mbar
The table below shows the displayed readings at various pressures for selected gases when engineering units
selected is in mbar.
Displayed Pressure Readings vs. True Pressure for selected gases - Engineering units in mbar
True Pressure
N2
Ar
He
O2
CO2
KR
Freon12
Freon22
D2
Ne
CH4
0 mbar
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
.0001 mbar
.0001
.0001
.0001
.0001
.0001
.0001
.0001
.0001
.0001
.0001
.0001
.0003 mbar
.0003
.0003
.0003
.0003
.0003
.0003
.0003
.0003
.0003
.0003
.0003
.0006 mbar
.0006
.0006
.0006
.0006
.0006
.0004
.0006
.0006
.0006
.0006
.0006
.0013 mbar
.0013
.0009
.0011
.0013
.0015
.0005
.0020
.0020
.0017
.0009
.0023
.0027 mbar
.0027
.0019
.0021
.0027
.0031
.0013
.0041
.0041
.0032
.0020
.0044
.0067 mbar
.0067
.0044
.0053
.0067
.0059
.0031
.0101
.0093
.0080
.0047
.0102
.0133 mbar
.0133
.0088
.0107
.0129
.0146
.0064
.0195
.0179
.0161
.0095
.0203
.0260 mbar
.0260
.0174
.0214
.0263
.0295
.0126
.0398
.0362
.0323
.0187
.0405
.0666 mbar
.0666
.0431
.0539
.0655
.0731
.0313
.0966
.0919
.0799
.0463
0.100
0.130 mbar
0.130
.0857
0.110
0.120
0.140
.0623
0.190
0.180
0.160
0.100
0.210
0.260 mbar
0.260
0.160
0.210
0.250
0.270
0.120
0.360
0.340
0.330
0.180
0.410
0.666 mbar
0.666
0.410
0.570
0.640
0.650
0.280
0.810
0.790
0.91
0.470
1.04
1.33 mbar
1.33
0.790
1.25
1.29
1.26
0.530
1.39
1.38
2.06
0.990
2.13
2.66 mbar
2.66
1.51
2.95
2.58
2.27
0.930
2.15
2.21
5.50
2.11
4.43
6.66 mbar
6.66
3.26
17.9
6.63
4.45
1.70
3.26
3.49
327
6.98
10.0
13.3 mbar
13.3
5.33
OP
13.7
6.62
2.37
3.94
4.51
OP
28.6
37.1
26.6 mbar
26.6
7.73
OP
29.7
8.78
3.05
4.42
4.95
OP
778
473
66.6 mbar
66.6
10.4
OP
103
10.9
3.42
5.05
5.51
OP
OP
1012
133 mbar
133
11.7
OP
278
12.3
3.65
6.23
6.54
OP
OP
OP
266 mbar
266
13.0
OP
393
16.3
4.42
7.98
8.55
OP
OP
OP
400 mbar
400
15.0
OP
506
22.5
4.78
9.18
10.0
OP
OP
OP
533 mbar
533
17.9
OP
646
29.8
5.25
10.1
11.2
OP
OP
OP
666 mbar
666
21.4
OP
805
38.2
5.61
11.0
12.2
OP
OP
OP
800 mbar
800
25.0
OP
973
48.5
5.91
11.8
13.2
OP
OP
OP
933 mbar
933
29.0
OP
1140
61.4
6.19
12.5
14.2
OP
OP
OP
1011 mbar
1011
31.5
OP
1250
71.8
6.33
13.0
14.7
OP
OP
OP
1060 mbar
1060
33.4
OP
1320
79.1
6.45
13.2
15.1
OP
OP
OP
1190 mbar
1019
37.9
OP
OP
105
6.65
13.9
16.0
OP
OP
OP
1330 mbar
1330
43.3
OP
OP
147
6.77
14.7
16.9
OP
OP
OP
Values listed under each gas type are in mbar.
Notes:
1) OP = Overpressure indication; display will read “overpressure”.
Examples:
1) Gas used is nitrogen. Display shows pressure measurement of 13.3 mbar. True pressure of nitrogen is 13.3 mbar.
2) Gas used is argon. Display shows pressure measurement of 11.7 mbar. True pressure of argon is 133 mbar.
3) Gas used is CO2. Display shows pressure measurement of .0731 mbar. True pressure of CO2is .0666 mbar.

Instruction Manual CVM201 Super Bee
InstruTech, Inc. Page 18
7 Analog Output
The CVM201 provides either a non-linear or a
log-linear analog output. Additionally it can provide
a linear 0-10 Vdc analog output.
Non-Linear Output
The first Convectron® gauge controllers produced a non-
linear output signal of 0.375 to 5.659 Vdc for 0 to 1000
Torr of N2, roughly in the shape of an "S" curve, as shown
at right. Granville-Phillips® adopted the same output
curve for most of their Mini-Convectron® modules and
controllers with non-linear output (although in recent
years, some Granville-Phillips® controllers may output
variations of the original S-curve).
The non-linear output from InstruTech convection
gauges, modules and controllers duplicates the original
S-curve of 0.375 to 5.659 Vdc for 0 to 1000 Torr.
The tables shown in section 7.1 and 7.2 contain the
lookup data for converting the non-linear output voltage
into pressure values for nitrogen and various other gases.
Log-Linear Output
Many InstruTech modules and controllers also provide a
log-linear output signal, as an alternative to the non-
linear signal described above. This output, shown at
right, is a 1 Volt per decade signal that may be easier to
use for data logging or control.
The table shown in section 7.3 and 7.4 contain the lookup
data and provides the formulas for converting the
log-linear output voltage into pressure values for
nitrogen and various other gases.
Linear 0-10 Vdc Analog Output
The CVM201 also provides a linear 0-10 Vdc analog output. The linear output voltage can be any value between 10
mV and 10 V corresponding to displayed pressure between 1 mTorr and 1000 Torr. However, the useful range of the
linear analog output is three decades. For example if the minimum pressure selected is 1 mTorr (1.0 x 10-3 Torr) with
a corresponding minimum voltage output of 0.01 volts, then maximum pressure selected to correspond to a
maximum voltage output of 10 volts should not exceed 1.0 Torr. If your application requires the analog output to
cover a pressure range exceeding three decades then consider using the non-linear or the log-linear analog output.
Note that an analog output of less than 0.01 volts (to near 0 volt) may indicate a damaged or faulty sensor.
Non-Linear Analog Output
10+3 10-3 10-2 10-1 10010+1 10+2
1
2
3
4
5
6
Pressure - Torr
Output - Volts
Non-Linear Analog Output
10+3 10-3 10-2 10-1 10010+1 10+2
1
2
3
4
5
6
Pressure - Torr
Output - Volts
10+3 10-3 10-2 10-1 10010+1 10+2
1
2
3
4
5
6
Pressure - Torr
Output - Volts
10+3 10-3 10-2 10-1 10010+1 10+2
2
3
4
5
6
7
8
Pressure - Torr
Output - Volts
Log-Linear Analog Output
1
10+3 10-3 10-2 10-1 10010+1 10+2
2
3
4
5
6
7
8
Pressure - Torr
Output - Volts
Log-Linear Analog Output
1