Kobold MAS Series User manual

KOBOLD MAS Series
Thermal Mass
Flowmeters
March1997
r2_12-13
Part Number:
IM-82
KOBOLD Instruments Inc
1801 Parkway View Drive · Pittsburgh, PA 15205
[phone]·[phone]·Fax[phone]

MAS Instruction Manual
Page 1
The purpose of this instruction manual is to cover the following
KoboldInstrumentsIncproducts:
Model MAS-1000 Flowmeter with Polyamide body and display.
Model MAS-2000 Flowmeter with Polyamide body and no display.
Model MAS-3000 Flowmeter with stainless steel flow body and
display.
ModelMAS-4000 Flowmeter withstainlesssteelflow bodyand no
display.
ModelMAS-1100 Flowmeterwith aluminum bodyanddisplay.
ModelMAS-2100Flowmeterwithaluminumbodyandnodisplay.
Kobold Instruments’ MAS Series Flowmeters measure the mass
flowrateofgasesinrangesfrom0-10standardcubiccentimeters
perminute(SCCM) to0-500standardlitersperminute(SLM). For
mostmodels,accuracyis1.5%offullscaleoverawidetemperature
andpressure range, andtime response is2 seconds towithin 2%
of final flow. Certain models are rated at 1% or 5% of full scale.
The MAS is ideal for a complete range of gas flow applications
includinggeneralprocesscontrol,laboratories,instrumentOEM’s,
gaspanels, and flowcalibration.
1
INTRODUCTION
Figure 1-1
Tiltable Display is Viewed
from any Angle
1.1
Purpose

MAS Instruction Manual
Page 2
CAUTION! Any application whatsoever related to humanCAUTION! Any application whatsoever related to human
CAUTION! Any application whatsoever related to humanCAUTION! Any application whatsoever related to human
CAUTION! Any application whatsoever related to human
respiration must have the written consent of Koboldrespiration must have the written consent of Kobold
respiration must have the written consent of Koboldrespiration must have the written consent of Kobold
respiration must have the written consent of Kobold
Instruments Inc.Instruments Inc.
Instruments Inc.Instruments Inc.
Instruments Inc.
The versatile MAS Flowmeter digitally displays the mass flow
rate directly in engineering units or percent of full scale. The
displayis tiltable over180°for easyviewingand can beremoved
forremotemountingonafrontpanel.
TheKobold MASdirectly monitorsthe mass flow rate of the gas.
Thismeansitmeasuresmolecularflow–themeasurement quality
ofdirect concerninmostapplications, suchashumanrespiration,
chemical processes, combustion, and heating or cooling. No
temperatureorpressure correctionsarerequired,asin thecaseof
mostotherflowmonitoringdeviceslikerotameters,turbinemeters,
andorificeplates.
Figure 1-2
MAS Operation
and Features
Direct Monitoring of
MassFlow.
No temperature or
pressure corrections
required.
Unexcelled Performance.
● ± 1.5% accuracy.
● 0.5% repeatability.
● 2 second response time
TiltableDisplay.
9 positions provide easy
viewing from any angle.
Connector.
9-Pin "D" Sub-type. Has
0-5 VDC or 4-20 mA
(optional) output signal
linearly proportional to
mass flow rate.
Input Power Jack.
Accepts 12 to15 VDC or
24 VDC input power from
Kobold power supply or
customer supplied power.
Inlet Screen.
Filters out particulates.
Easily removable.
Inlet/OutletFittings.
Available with Female
NPT or Swagelok®
style compression
fittings.
DigitalDisplay.
Gives mass flow
rate in engineering
units.
Zero and Span
Potentiometers.
Adjustable from
outside of enclosure.
Patented Sensor
Tube.
Straight,large-I.D.
sensor tube is easy
to clean.
Patented Laminar
FlowBypass.
Provides a variety of
flow ranges. Unique
cutouts make range
changes easy.
FlowBody.
Corrosion resistant
plastic or stainless
steel. FKM "O"-
rings standard.
MountingHoles.
The MAS mounts in any
position for convenience
ofinstallation.

MAS Instruction Manual
Page 3
1.2
Principle of
Operation
Figure 1-3
Two Flow Paths
Figure 1-4
Measuring Sensor Flow
*U.S. Patent No. 4,487,062.
The MAS Flowmeter is a transducer requiring a 12-15 VDC (24
VDCoptional)externalpowersource.A0-5VDCoroptional4-20
mA output singal linearly proportional to gas mass flow rate is
providedforrecording,data-logging,orcontrol.A9-Pin“D”sub-
connectorisprovidedforpowerinputandsignaloutput. TheMAS
isavailablein severalbasicconfigurationswitheither 1/4inchNPT
(female)or1/4to1/2
inchO.D.tubecompressioninlet/outletfittings,
withorwithout the digitaldisplay,or the optional powersupply.
Gas enters the MAS flow body and divides into two flow paths.
Mostoftheflowgoesthroughthelaminarflowbypass.Thiscreates
apressuredrop thatforcesasmallfractionofthe flow throughthe
sensortube.
TWO COILS
SENSOR
TUBE
LAMINAR FLOW BYPASS
m
2
P
1
P
2
•
m
•
m
1
•
The patented* straight sensor tube is mounted parallel to the
bypassflowpath. Since bothpathsareperfectlylaminar,theratio
of the total flow (
˙
m
) to the sensed flow (
˙
m
1) is constant. Two
resistance temperature detector (RTD) coils around the sensor
tubedirect a constant amount ofheat into the gas stream.
RTD COILS
R
1
, T
1
R
2
, T
2
m
·1H
0
CONSTANT HEAT, H
FIRST LAW OF THERMODYNAMICS
(HEAT IN = HEAT OUT)
H = m
·
1
C
p
(T
2
– T
1
) + H
0
m
·= H–H
0
C
p
∆T

MAS Instruction Manual
Page 4
In actual operation, the gas mass flow carries heat from the
upstreamcoiltothedownstreamcoil.Theresultingtemperature
differenceT2–T1isdetectedbytheRTD coils and givestheoutput
signal. Since the molecules of the gas carry away the heat, the
output signal is directly and linearly proportional to gas mass
flow.
MAS's patented laminar flow bypass makes changing of flow
rangeseasy with thepropercalibration facilities. Eachof the two
bypasses in the optional Laminar Flow Bypass Set has a
combinationofrectangularslotsalongitscircumferenceasshown
inFigure 1-5 below.
To change the flow range of your MAS, follow the instructions
providedwiththeKobold Model EL LaminarFlowBypassSetand
cutawaythe “gate(s)”leadingtotherightcombinationof laminar
flow paths in one of the two bypasses. This procedure requires
propercalibration facilities andminimal skill inelectronics.
FLOW RANGES
_________________________________________________________________
Code SCCM Code S L M
_________________________________________________________________
01 0-10 07 0-1
02 0-20 08 0-2
03 0-50 09 0-5
04 0-100 10 0-10
05 0-200 11 0-20
06 0-500 12 0-30
13 0-40
_________________________________________________________________
Flowrangesspecifiedare for an equivalent flow of nitrogen at 760 mm
Hg and 21°C (70°F). Other ranges are available.
GASES
Most gases; check compatibility with wetted materials; specify
whenordering.
DISPLAY
31/2digitLCD(0.5inches tall); removable for remote mounting.
Figure 1-5
Changing Flow Ranges
is Easy with MAS’s
Patented Bypass
1.3
Specifications
A
A
“GATES”
SECT. A-A

MAS Instruction Manual
Page 5
OUTPUT SIGNAL
Linear0-5VDC standard, 1000 ohms min. load impedance;4-20
mAoptional,50 to 500 ohms loopresistance.
POWER REQUIREMENTS
12-15VDC nominal;100mA max(24 VDCoptional,specify when
ordering).
ACCURACY
±1.5%offull scale including linearity over 15 to25°Cand5 to 60
psia(0.35 to 4.2kg/cm2);with specialcalibration±1% of fullscale
accuracyat a specific temperature and pressure is available.
REPEATABILITY
±0.5%offullscale.
TEMPERATURE COEFFICIENT
0.15% of full scale per °C, or better.
PRESSURE COEFFICIENT
0.01%of full scale perpsi(0.07 kg/cm2),orbetter.
RESPONSE TIME
800 ms time constant; 2 seconds (typical) to within ±2% of final
valueover 25 to 100% of full scale.
PRESSURE DROP
____________________________________________________________
Typical MaximumPressureDrop
Flow Rates (cmofWater)
_____________________________________________________________
100 SCCM .025
1 SL M .454
10 S L M 6.00
20 S LM 23.83
30 S LM 45.60
40 S LM 83.36
___________________________________________________________
GAS PRESSURE
150psi(10kg/cm2)gaugemax;20psi(1.4kg/cm2)gaugeoptimum.
LEAK INTEGRITY
1×10–4 SCCS of helium max to outside environment.
GAS AND AMBIENT TEMPERATURE
0 to 50°C.

MAS Instruction Manual
Page 6
WETTED MATERIALS
5% glass-filled Polyamide 6/6; 316 stainless steel; FKM “O”-
WEIGHT
2 lb. (0.9 kg) net; 3 lb. (1.4 kg) shipping.
Dimensions
1.15
(29.21)
3.05
(77.47)
4.16
(105.66)
(WITHOUT
DISPLAY)
5.38
(136.65)
3.50 (88.90)
1
/ 4 " NPT
6.68 (169.67)
1
/ 4 " SWAGELOCK
®
ALL DIMENSIONS IN INCHES
0.58
(14.73) 1.16
(29.46)
0.56
(14.22)
6-32 X 0.15 DP.
(SELF TAPPING)
0.75 (19.05)
0.38
(9.65)
0.13 (3.30)
2.75
(69.85)
3.00
(76.20)
0.125 DIA. THRU PANEL-2 PLACES;
FOR TWO 4-40 FLAT HEAD SCREWS
0.25 DIA. THRU; FOR 4 WIRES
0.88 (22.35)
1.00 (25.4)
PANEL MOUNTING HOLES
DIMENSIONS IN INCHES
(DIMENSIONS IN MILLIMETERS IN PARENTHESES)
SIDE VIEW END VIEW BOTTOM VIEW
rings standard, FFKM and silicone O-rings optional.

MAS Instruction Manual
Page 7
1.4
Options
Manyoptions are available for yourKobold MAS. Please consult
Kobold’scurrent PriceList for the respective prices.
V4 (Optional) 4-20mAoutputsignal
C( ) Cableassembly,specifycabletype(roundorribbon)and
length
T2 1-5 Channel Power Supply, in NEMA Box, 115 VAC
T4 1-5 Channel Power Supply, in NEMA Box, 230 VAC
T5 PowerSupply,foronechannel,110VAC
T6 PowerSupply,foronechannel,230VAC
UV Upstream valve
DV Downstreamvalve
MS Replacementmass flowsensor,includes “O”-rings and
mountingflanges
OV Completeset ofFKM “O”-rings
TP Tipplatefor electrical enclosure
RD–( ) Remotedisplay
* U.S.and foreign patents pending.
® Registered trademarks: Swagelok, VCO, VCR–Crawford Fitting Co.

MAS Instruction Manual
Page 8
2
INSTALLATION
2.1
Receipt of Your
MAS
When
the equipment is received, carefully check the outside
packingcarton fordamage incurred in shipment. Ifthe packing
carton is damaged, the local carrier should be notified at once
regardingtheirliability.Kobold’s Customer Service Department
shouldalsobenotifiedimmediately.
CustomerServicePhoneNumber:
USA(412)788-2830,orFax(412)788-4890
ForourcustomersotherthantheUSA,CanadaandMexicoplease
callthedistributorfromwhomyoupurchasedyourMASorcallour
headofficeinGermanyfortheKobold location nearest you:
Germany49(0)61-92-29-90orFax49(0)61-92-23-398
Remove the packing slip from its envelope and verify that the
carton contains all parts listed. Inspect the carton and packing
materialthoroughly to ensurethat no spareparts or accessories
are mistakenly discarded. In case of shortages, please contact
Customer Service at the above phone number, or they may be
contacted in writing at the address listed in the next section.
Please do not return any equipment without a Return Material
Authorization, which is obtained from the Customer Service
Department.Informationdescribingtheproblem,correctiveaction
orworktobeperformedatthefactory,thepurchaseordernumber
that the equipment was purchased under, and the name of the
persontocontact mustbeincludedwiththereturnedequipment.
The use of a Return Material Authorization is for your benefit. It
makes the proper service and return of your equipment much
easiertoaccomplish.
Returnshippingaddress:
USA KOBOLD INSTRUMENTS INC.
1801Parkway ViewDrive
Pittsburgh,PA15205
Non-North American customers may contact the KOBOLD
Messring GmbH Customer Service Department Technical
Assistanceat:
Europe KOBOLD MESSRING GmbH
Nordring22-24
65719Hofheim/Ts.
Germany
NOTE:Equipmentreturnedforrepairthatisfoundtobecompletely
operational will be subject to the current “no problem found”
billingrate.
2.2
Return Shipment

MAS Instruction Manual
Page 9
CAUTION! The maximum pressure and temperature in theCAUTION! The maximum pressure and temperature in the
CAUTION! The maximum pressure and temperature in theCAUTION! The maximum pressure and temperature in the
CAUTION! The maximum pressure and temperature in the
flow line in which your MAS is to be installed must notflow line in which your MAS is to be installed must not
flow line in which your MAS is to be installed must notflow line in which your MAS is to be installed must not
flow line in which your MAS is to be installed must not
exceed 150 psig (10 kg/cmexceed 150 psig (10 kg/cm
exceed 150 psig (10 kg/cmexceed 150 psig (10 kg/cm
exceed 150 psig (10 kg/cm22
22
2gauge) or 150gauge) or 150
gauge) or 150gauge) or 150
gauge) or 150°F (65F (65
F (65F (65
F (65°C),C),
C),C),
C),
respectively.respectively.
respectively.respectively.
respectively.
Inorderto ensureasuccessfulinstallation,inlet andoutlet tubing
orpipingshouldbeinaclean state prior to plumbing your MAS to
the system. MAS is applicable to clean gas onlyclean gas only
clean gas onlyclean gas only
clean gas only because
particulatesandotherforeignmattermayclogthesensortubeand
laminar flow element over a period of time. If the gas contains
particulatematter,installahigh-efficiency, 50 to 100 micron,in-
line filter upstream of the MAS.
Do not locate the MAS Flowmeter in areas subject to sudden
temperaturechanges,moisture,drafts,ornearequipmentradiating
significant amounts of heat. Allow adequate space for cable
connectorsandwiring. If your MASistobemountedinotherthan
ahorizontal position, the zero willneed adjustment. See Section
5.2, RECALIBRATION OVER THE SAME FLOW RANGE.
CAUTION! Be sure the arrow on the side of the transducerCAUTION! Be sure the arrow on the side of the transducer
CAUTION! Be sure the arrow on the side of the transducerCAUTION! Be sure the arrow on the side of the transducer
CAUTION! Be sure the arrow on the side of the transducer
points in the direction of flow.points in the direction of flow.
points in the direction of flow.points in the direction of flow.
points in the direction of flow.
TheMASmaybe mounted to achassiswithtwo6-32 self-tapping
screws. See Section 1.3, SPECIFICATIONS, for hole dimensions.
Your MASis suppliedwith either 1/4inchfemaleNPT (standard)
or 1/4, 3/8or1/2
inch compression inlet and outlet fittings. These
fittingsshouldnot be removedunlessyour MAS is beingcleaned
or calibrated for a new flow range. VCO®or VCR®fittings are
available on special order. 1/4-inch pipe requires a good quality
pastepipethread sealant andshouldbe installed in theinletand
outletfittings11/2turnsbeyond hand-tight.
CAUTION! Over-tightening will crack the fittings andCAUTION! Over-tightening will crack the fittings and
CAUTION! Over-tightening will crack the fittings andCAUTION! Over-tightening will crack the fittings and
CAUTION! Over-tightening will crack the fittings and
shift calibration.shift calibration.
shift calibration.shift calibration.
shift calibration.
Forthefirstinstallationof compressionfittings,simplyinsertthe
tubing into the fitting. Make sure that the tubing rests firmly on
theshoulderof thefittingandthatthe nutishand-tight.Scribethe
nutatthesixo’clockposition.Whileholdingthefittingbodysteady
with a back-up wrench, tighten the nut 11/4turns, watching the
scribemarkmakeonecompleterevolutionandcontinuetothenine
o’clock position. After this, the fitting can be reconnected by
snuggingwitha wrench. Do notfailtouseaback-upwrenchor the
inletfitting may bedamaged.
2.4
Plumbing
Connections
2.3
Mechanical
Installation

MAS Instruction Manual
Page 10
CAUTION! Do not mix or interchange parts of tube fittingsCAUTION! Do not mix or interchange parts of tube fittings
CAUTION! Do not mix or interchange parts of tube fittingsCAUTION! Do not mix or interchange parts of tube fittings
CAUTION! Do not mix or interchange parts of tube fittings
made by different manufacturers.made by different manufacturers.
made by different manufacturers.made by different manufacturers.
made by different manufacturers.
Finally,check the system’sentire flow path thoroughly forleaks
beforeproceeding to Section3,OPERATION.
CAUTION!Allinstrumentsareleak-testedpriorto shipping.CAUTION! All instruments are leak-testedpriortoshipping.
CAUTION!Allinstrumentsareleak-testedpriorto shipping.CAUTION! All instruments are leak-testedpriortoshipping.
CAUTION!Allinstrumentsareleak-testedpriorto shipping.
Tocheck yourinstallation, testthe fittings only. Do not useTo check your installation,test thefittings only.Do not use
Tocheck yourinstallation, testthe fittings only. Do not useTo check your installation,test thefittings only.Do not use
Tocheck yourinstallation, testthe fittings only. Do not use
liquid leak detectors such as Snoop® to search for leaksliquid leak detectors such as Snoop® to search for leaks
liquid leak detectors such as Snoop® to search for leaksliquid leak detectors such as Snoop® to search for leaks
liquid leak detectors such as Snoop® to search for leaks
inside or outside the MAS. Instead, monitor pressureinside or outside the MAS. Instead, monitor pressure
inside or outside the MAS. Instead, monitor pressureinside or outside the MAS. Instead, monitor pressure
inside or outside the MAS. Instead, monitor pressure
decay.decay.
decay.decay.
decay.
Figure 2-1
Plumbing Requirements
for Model’s 1100/2100
2.50"
(63.5 mm)
1
/ 2 " NPT PIPE
(5 DIAMETERS)
5.0"
(127 mm)
1
/ 2 " NPT PIPE
(10 DIAMETERS)
FLOW
➡
EXAMPLE: Cross Section
CORRECT
1/2" NPT pipe for
1/2" NPT flow body
INCORRECT
Avoid use of compression
fitting on inlet of flow body. The
reduction of internal diameter of
the fitting results in a “jet”, creating
noise and affecting calibration.
DO NOT reduce down right at the
inlet with 1/4" pipe.

MAS Instruction Manual
Page 11
MAS flowmeters require a single +12 to +15 VDC power supply
capableofproviding aminimumcurrentof100mA.The MAS can
alsobeconfigured for +24VDCpower at 100 mA.
Operatingpowerinputisviaeitherthe DC power jack or the 9-pin
“D”connectoronthesideoftheenclosure.KoboldofferstheModel
MAS-5000 single channel power supplies for single transducer
applications and the Model MAS-5100 for powering up to eight
transducersthroughthe"D"connector.
CAUTION! Do not supply + DC power at the “D” connectorCAUTION! Do not supply + DC power at the “D” connector
CAUTION! Do not supply + DC power at the “D” connectorCAUTION! Do not supply + DC power at the “D” connector
CAUTION! Do not supply + DC power at the “D” connector
while using an MAS-5000 power supply at the DC powerwhile using an MAS-5000 power supply at the DC power
while using an MAS-5000 power supply at the DC powerwhile using an MAS-5000 power supply at the DC power
while using an MAS-5000 power supply at the DC power
jack. Do not plug power connector into DB9 connector.jack. Do not plug power connector into DB9 connector.
jack. Do not plug power connector into DB9 connector.jack. Do not plug power connector into DB9 connector.
jack. Do not plug power connector into DB9 connector.
Damage to electronics will result.Damage to electronics will result.
Damage to electronics will result.Damage to electronics will result.
Damage to electronics will result.
ThestandardMASisprovidedwitha9-pin“D”subtypeconnector
located on the side of the MAS enclosure as shown in Figure 2-2.
Thepinnumbersforthis“D”connectorarealsoshowninFigure2-
2,andthe pinassignmentsaregiveninTable2-1 on thenextpage.
Theoutputsignalis obtained from the 9-pin“D”connector.A0to
5VDCoutput signal linearly proportionaltogasmass flow rateis
standard. A 4-20 mA current loop signal is optionally available.
Thematingconnector is included.
WhentheMAS isconfiguredforaremote display,connectionsare
made via the 9-pin “D” connector. Power connections for the
displayandtransduceraresharedinthismodeunlesstheaccessory
MAS-5000powersupplyisused.
Figure 2-2
“D” Connector and DC
Power Jack Location and
Number Assignments
6
7
8
9
1
2
3
4
5
“D” CONNECTOR
DC POWER JACK
2.5.1
9-Pin “D”-Connector
Pin Assignments
2.5
Electrical
Connections

MAS Instruction Manual
Page 12
The following connection points can be made through the “D”
connectoror,inOEMapplications,madethroughthecircuitboard
solderpadconnections.
Thedisplay padconnectionsareshown forapplicationsrequiring
remotemountingofthe digital display. Thelettersappearonthe
displaycircuit board andare shown in Figure 2-3.
___________________________________________________________
Pin No. Function Display Pad
____________________________________________________________
1 NoConnection N/A
2 SignalCommon N/A
3 0 to +5 VDC Flow Signal N/A
4 + Power Supply (12 or 24 VDC) *1, *2 (A)
5 Remote Display Flow Signal (D)
6 RemoteDisplayReference (C)
7 PowerCommon(B)
8 4to20mA Return (Common) N/A
9 4 to 20 mA Output N/A
____________________________________________________________
NOTE:thenumberson the connector plug maynotagreewiththe
numbering system as it appears on our Figure 2-2 (on previous
page).Itisimportanttomakesurethattheproperwiresarein the
properlocationratherthan the proper number. Mostconnectors
utilizea standard numberingscheme but there are afew that do
not.
Theremotedisplayconnectsthroughthe9-pin“D”connectoronly.
The pads A-D in the top right of the main circuit board are for
integraldisplaymountingonly.
*1 Power supply voltage mustbe specified attime oforder. Operating a12 VDCmeter at
24 VDC will cause damage. Running a 24 VDC meter at 12 VDC will result in faulty
operation.
*2 Donot supply + DC poweratthe “D” connector while usinga powersupply at the DC
powerjack. Both supplies may bedamaged.
Figure 2-3
Printed Circuit Board
Input/Output Solder Pad
Assignments (wires shown
are typical)
Table 2-1

MAS Instruction Manual
Page 13
As shown in Figure 2-4, the digital display on your MAS may be
removed and mounted remotely on a front panel. The MAS
transducerismounted atanyconvenientlocationin yoursystem.
Remoteinstallation is notrecommended unless you possess the
proper soldering tools and skills to accomplish the job. Remote
installation of the digital display is accomplished by following
thesesteps:
1. Remove the digital display from your MAS by following the
procedure described in Section 2.5.3, OEM ELECTRICAL C ONNEC-
TIONS.
2. Gain access to the printed circuit board (PCB) also by following
the procedure in Section 2.5.3, OEM ELECTRICAL C ONNECTIONS.
3. Verycarefully unsolderthefourshortleadsfrom thePCBtothe
display.
4. Gain access to the display circuit board by removing the two
snaprings(No. 36) and openingthe“clamshell”displayenclo-
sure. Remove the four short wires by carefully unsoldering.
Solderthelongerfourwires(26AWG,100ft.maxshieldedcable
recommended)tothedigital display and solder theotherends
tothe appropriate pinnumbers of the 9-pin “D”connector as
showninFigure 2-3 and Table2-1(onprevious page).
5. Reassemble the MAS,replacing the displaybase (No. 35)with
the Model TP Plain Top Cover (No. 28).
6. Make the necessary plumbingconnectionstotheunit.
7. Mountthe digitaldisplayasshowninFigure2-4referringtothe
panelmounting holedimensions inSection 1.3, SPECIFICATIONS.
2.5.2
Remote Installation of
Digital Display
Figure 2-4
Remote Installation of
Digital Display

MAS Instruction Manual
Page 14
2.5.3
OEM Electrical
Connections
2.5.4
Using Kobold’s Single,
Dual, and Flo-Box™
Electronics
TheOEM version MASflowmeter has an electrical port(hole) on
its side for electrical input/outputs. This port is just above the
inputpowerjack(seeFigure 2-2). Wires entering theMASviathis
portare solderedtotheprintedcircuit boardasshowninFigure 2-
3.The solderpad assignments are given inTable 2-1.
How to Gain Access to the MAS’s Printed Circuit Board (PCB):
Togain accessto thePCB to make the solder connections, please
refertothe exploded view inAppendixAand follow thesesimple
steps.
1. If your MAS has the digital display:
(a) First,remove the displaybycarefully rotating thedisplay
until it hits the top plate. Slowly continue to rotate until this
lever arm action snaps out the two yokes holding the display
(Nos.30).Use extra cautionduringthis operation as excessive
forcewill break the delicatewire connections. Carefully move
the display assembly to expose the two screws securing the
displaybase(No.35).Donotexertexcessiveforceonthedisplay
while rotating as doing so could crack the LCD display.
(b) Next,remove thetwo screws (Nos. 21) inthe displaybase
(No. 35) and the two screws (also Nos. 21) in the back of the
enclosure(No.10).
(c) Thetop, front, andback sides ofthe enclosure cannow be
removed,(thefrontslidesouttowardsyouandperpendicularto
the flow path) exposing the PCB.
2. If your MAS does not have the digital display:
(a) Removethelabel (No. 29) fromtheplaintopcover(No.28)
toexpose the twoscrews(Nos. 21).
(b) Thenfollowsteps1(b)and1(c)above.
Toreassemble,just reverse theprocess.
For applications requiring flow totalization or alarms simply
ordertheoptionalModelEC-( )cabletoconnecttotherearpanel
of Kobold Instruments’ Single-Channel, Dual-Channel, or Flo-
Box(1-5Channels)Electronics.TheKoboldelectronicswillprovide
youwithaselectabledigitalreadoutforeachchannel,inputpower,
high,low, or windowalarms, and optionalflow totalization.

MAS Instruction Manual
Page 15
3
OPERATION
3.1
Quick Operating
Instructions
3.2
Notes to Operating
Instructions
Quick operating instructions are given on the first page of this
manual.
FollowingareimportantnotesandcommentsregardingtheQuick
OperatingInstructions.
NOTE 1 REFERENCING THE FLOW RATE TO OTHER TEMPERATURE AND
PRESSURE CONDITIONS:
Thegasflow rate outputofyour MAS is referencedto“standard”
conditionsof21°C(70°F)and760mmofmercury(1atmosphere),
unlessyouhavespecifiedotherwise.Besureyouknowthereference
conditionsofyourMAS,becauseitmaymakeadifferenceifyouare
comparingtheoutput oftheMASwithanother typeofflowmeter.
Forexample,the outputreadingoftheMAS willbeapproximately
7% lower if it is referenced to 0°C rather than 21°C. Appendix B
shows how to convert the flow rate output of your MAS to other
standardconditionsandhowtofindtheflowratereferencedtothe
actualtemperatureandpressureconditionsinthepipewhereyour
MAS is located.
NOTE 2 ACCURACY:
Thestandard accuracyoftheMASis ±1.5%offullscale.The±1.5%
offullscaleaccuracymeansthe0-5VDCoutputsignalisaccurate
towithin±0.1 VDC, andthe4-20 mA outputisaccurate to within
±0.4mA.This means, for example,thattheoutput signal forzero
flowcanbeasmuchas±0.1VDCor±0.4mA.Pleasenoteifyouget
anoutput signal atzero flow (as long asit is withineither of these
two ranges) it does not mean your MAS is malfunctioning. For
MAS’swiththe digital readout, theaccuracyissimply 1.5% times
the full scale flow rate listed on your MAS’s front label. For
example, if your full scale is 10 SLM, the digital readout will be
accurateto±0.2SLM,andthereadingat zeroflowmaybeasmuch
as±0.2 SLM and still be within thestated accuracy specification.
NOTE 3 OVERRANGING:
If the flow rate exceeds the full scale range listed on your MAS’s
frontlabel, theoutputsignalanddigital display(ifyouhaveit) will
reada higher value.
TheMAShasnotbeencalibratedforoverrangedflowsandprobably
willbebothnon-linearandinaccurate.Ifthesupply voltageisonly
12 VDC, the overranged reading may only exceed the full scale
readingby10%maximum.Ifthesupplyvoltageishigher,suchas
withthe24 VDCoption,thentheoutputcanexceed full scalebyas
muchas50%, or more. Ifyouhavethe digital display,thedisplay
cannotexceedthefourdigits1999.Iftheflowrateexceeds1999the

MAS Instruction Manual
Page 16
rightmostdigitswill blank and onlytheleft-hand“1”will appear
onthedisplay.
Overrangeconditionsare indicated by thedisplayand/oroutput
goingtoahighlevel,abovethefullscale range.Aftertheoverrange
conditionhas been removed,it may take several secondsfor the
MAStorecoverandresumenormaloperation.Thiswillnotharm
theinstrument.
NOTE 4 OPTIONAL 4-20 mA OUTPUT S IGNAL:
The4-20 mAoutputsignalcurrentflows fromthe4-20mAoutput
pin on the “D” connector through the load (50 to 500 ohms) to
ground (see Section 2.5.1, 9-PIN “D” CONNECTOR P IN A SSIGNMENTS).
Figures 3-1 and 3-2 illustrate single and multiple installations
withcurrentloop outputs.
NOTE 5 ZERO AND SPAN ADJUSTMENTS:
Thezeroandspanpotentiometers are accessed through marked
portsontherightsideofyourMAS.Ifyourzerooutputismorethan
±1.5%of full scale,you may adjustthe zero potentiometerwhen
youare absolutely certain thatyou have zero flow.
Sincetheoutputdoesnotindicatenegativenumbers,itisnecessary
toadjust down from aslightly positive reading. Slowlyrotate the
zeropotclockwiseuntilapositivereadingisindicated.Tocomplete
thezero adjustment,slowly turn the pot counterclockwiseuntil
zeroisreached.
Normally, span adjustments are not made unless you areNormally, span adjustments are not made unless you are
Normally, span adjustments are not made unless you areNormally, span adjustments are not made unless you are
Normally, span adjustments are not made unless you are
calibrating your MAS, as described in Section 5.calibrating your MAS, as described in Section 5.
calibrating your MAS, as described in Section 5.calibrating your MAS, as described in Section 5.
calibrating your MAS, as described in Section 5.The span
adjustmentshould not beusedunless you havea known precise
non-zeroflow rate thatyouwish to match.
NOTE 6 ATTITUDE:
Unless specified otherwise, your MAS has been calibrated for
installationwiththe flow direction inthehorizontalplane (±15°)
with the enclosure facing upward. If your actual installation
orientation is different, you will have to make a small zero
adjustment.

MAS Instruction Manual
Page 17
Figure 3-2
Multiple Installation
4-20 Hookup
Figure 3-1
Single Unit 4-20 Hookup

MAS Instruction Manual
Page 18
4
MAINTENANCE
4.1
General Statement
4.2
Flow Path Cleaning
YourMAS essentiallyrequiresnomaintenanceand hasnoregular
maintenanceschedule, other than periodicflow path cleaning if
the gas is dirty. Calibrations may be scheduled once or twice
yearly,dependingontheaccuracytobemaintained,orasneeded.
It is recommended that your MAS be returned to KoboldIt is recommended that your MAS be returned to Kobold
It is recommended that your MAS be returned to KoboldIt is recommended that your MAS be returned to Kobold
It is recommended that your MAS be returned to Kobold
Instrumentsifcleaning,repair,orrecalibrationare needed.Instrumentsifcleaning,repair,orrecalibrationareneeded.
Instrumentsifcleaning,repair,orrecalibrationare needed.Instrumentsifcleaning,repair,orrecalibrationareneeded.
Instrumentsifcleaning,repair,orrecalibrationare needed.
This is usually your most cost-effective and reliableThis is usually your most cost-effective and reliable
This is usually your most cost-effective and reliableThis is usually your most cost-effective and reliable
This is usually your most cost-effective and reliable
alternative.alternative.
alternative.alternative.
alternative.
The flow path (wetted parts) ofthe MAS are 5% glass-filled
Polyamide 6/6;316stainlesssteel(sensortube);and FKM “O”-rings
(standard).
CAUTION! IF YOU WISH TO CLEAN YOUR MAS PURGECAUTION! IF YOU WISH TO CLEAN YOUR MAS PURGE
CAUTION! IF YOU WISH TO CLEAN YOUR MAS PURGECAUTION! IF YOU WISH TO CLEAN YOUR MAS PURGE
CAUTION! IF YOU WISH TO CLEAN YOUR MAS PURGE
IT THOROUGHLY BEFORE DISCONNECTING FROM THEIT THOROUGHLY BEFORE DISCONNECTING FROM THE
IT THOROUGHLY BEFORE DISCONNECTING FROM THEIT THOROUGHLY BEFORE DISCONNECTING FROM THE
IT THOROUGHLY BEFORE DISCONNECTING FROM THE
GAS LINE WHEN TOXIC OR CORROSIVE GASES AREGAS LINE WHEN TOXIC OR CORROSIVE GASES ARE
GAS LINE WHEN TOXIC OR CORROSIVE GASES AREGAS LINE WHEN TOXIC OR CORROSIVE GASES ARE
GAS LINE WHEN TOXIC OR CORROSIVE GASES ARE
USED. NEVER RETURN AN MAS TO KOBOLDUSED. NEVER RETURN AN MAS TO KOBOLD
USED. NEVER RETURN AN MAS TO KOBOLDUSED. NEVER RETURN AN MAS TO KOBOLD
USED. NEVER RETURN AN MAS TO KOBOLD
INSTRUMENTS OR ANY OTHER REPAIR ORINSTRUMENTS OR ANY OTHER REPAIR OR
INSTRUMENTS OR ANY OTHER REPAIR ORINSTRUMENTS OR ANY OTHER REPAIR OR
INSTRUMENTS OR ANY OTHER REPAIR OR
CALIBRATION FACILITY WITHOUT FULLYCALIBRATION FACILITY WITHOUT FULLY
CALIBRATION FACILITY WITHOUT FULLYCALIBRATION FACILITY WITHOUT FULLY
CALIBRATION FACILITY WITHOUT FULLY
NEUTRALIZING ANY TOXIC GASES TRAPPED INSIDE.NEUTRALIZING ANY TOXIC GASES TRAPPED INSIDE.
NEUTRALIZING ANY TOXIC GASES TRAPPED INSIDE.NEUTRALIZING ANY TOXIC GASES TRAPPED INSIDE.
NEUTRALIZING ANY TOXIC GASES TRAPPED INSIDE.
Please refer to the exploded drawing of the MAS transducer in
AppendixAwhenusingthe following procedures. All cleaningof
theflow pathcan beaccomplished with Freon™, alcohol, or any
cleanersafe forthe listedmaterials.
Remove inlet and outlet fittings (Nos. 13), pull out the LFE hold-
downs (Nos. 12) and either replace or clean the inlet and outlet
screens(Nos.14).
Remove the inlet and outlet fittings as in Section 4.2.1, INLET AND
OUTLET S CREEN. The LFE (either No. 24 or No. 25) has a slightly
tapered shape with the larger diameter upstream (on the inlet
side).To remove the LFEfor cleaning, simply pushit out the inlet
sidefrom the outletsideusing a bluntobject which doesnotmar
the flow channels. A 3/8" (9 mm) nut driver is perfect for the job.
Whencleaning,be sure to carefullycleanallactive flow channels
in the LFE.
IMPORTANT:IMPORTANT:
IMPORTANT:IMPORTANT:
IMPORTANT: When reinstalling the LFE it is of utmost
importanceto press itin the correct distance. Referto Figure 4-1
forthecorrect distance.
4.2.1
Inlet and Outlet Screen
4.2.2
Laminar Flow Element
(LFE)

MAS Instruction Manual
Page 19
Figure 4-1
Proper LFE Location
Within The Flow Body
4.2.3
Sensor Tube
CAUTION! Opening the sensor cavity will shift calibra-CAUTION! Opening the sensor cavity will shift calibra-
CAUTION! Opening the sensor cavity will shift calibra-CAUTION! Opening the sensor cavity will shift calibra-
CAUTION! Opening the sensor cavity will shift calibra-
tion.tion.
tion.tion.
tion.
Do not remove the PCB Bracket (No. 7) unless it is absolutely
necessary to gain access to the sensor cavity. Doing so will shift
thecalibration morethan 1.5%. The remaining partsof theflow
pathare disassembledasshowninthe explodedviewinAppendix
A.Notethepositionof the insulation blanket beforeremovaland
re-installinthesamefashion. After removal, the sensortube(No.
5)canbecleanedbypurging,washingwithasolvent,orbyrodding
outthe0.031inch(.787mm) internaldiametertube witha0.029-
0.030inch(.737-.762mm)outsidediameterrodorwireorwiththe
ModelCKCleaningStyletavailable from Kobold Instruments. To
maximize the time response of your MAS, Kobold has designed
the sensortube with thinwalls. Therefore, when cleaning, beTherefore, when cleaning, be
Therefore, when cleaning, beTherefore, when cleaning, be
Therefore, when cleaning, be
extremely careful not to bend the sensor tube or to mar itsextremely careful not to bend the sensor tube or to mar its
extremely careful not to bend the sensor tube or to mar itsextremely careful not to bend the sensor tube or to mar its
extremely careful not to bend the sensor tube or to mar its
inlet or outlet edges.inlet or outlet edges.
inlet or outlet edges.inlet or outlet edges.
inlet or outlet edges.
Itis important when reinstalling thesensor to make sure thatno
torqueis imparted on thesensor tube. Torque canbe eliminated
byusing agood quality oxygen compatible greaseon thesensor
sealing “O”-rings. The sensor assembly should slide freely into
thecavity flanges without having totwist it. Twisting will impart
undesirable torque on the sensor and could lead to long term
shifting of the zero value. Also, take EXTREMEEXTREME
EXTREMEEXTREME
EXTREMEcare to not
disturbor unravelthe sensorwindings.
.61
(15.49)
.60
(15.24)
INLET OUTLET
.85
(21.59) .90 (22.86)
DIMENSIONS IN INCHES
(DIMENSIONS IN MILLIMETERS IN PARENTHESES)