Kobold MAS User manual

Operating Instructions
for
Electronic Mass Flow Meter
Model: MAS

MAS
page 2 MAS K05/0722
1. Contents
1. Contents........................................................................................................2
2. Note ..............................................................................................................3
3. Instrument Inspection....................................................................................3
4. Regulation Use .............................................................................................4
5. Application ....................................................................................................4
6. Operating Principle........................................................................................5
6.1 Measuring principle..............................................................................5
7. Mechanical Installation..................................................................................6
8. Electrical Connection ....................................................................................7
8.1 Power supply.......................................................................................8
8.2 Output signals......................................................................................9
8.3 Display.................................................................................................9
9. Operation....................................................................................................10
10. Totalizer......................................................................................................12
11. Maintenance ...............................................................................................13
12. Technical Information..................................................................................14
13. Conversion to other Working Conditions.....................................................15
14. Order Codes ...............................................................................................19
15. Dimensions.................................................................................................20
16. Disposal......................................................................................................21
17. Supplement.................................................................................................21
18. EU Declaration of Conformance .................................................................25
Sold by:
Kobold Messring GmbH
Nordring 22-24
D-65719 Hofheim
Tel.: [phone]
Fax: [phone]
E-Mail: [e-mail]
Internet: www.kobold.com

MAS
MAS K05/0722 page 3
2. Note
Please read these operating instructions before unpacking and putting the unit
into operation. Follow the instructions precisely as described herein.
The instruction manuals on our website www.kobold.com are always for currently
manufactured version of our products. Due to technical changes, the instruction
manuals available online may not always correspond to the product version you
have purchased. If you need an instruction manual that corresponds to the
purchased product version, you can request it from us free of charge by email
([e-mail]) in PDF format, specifying the relevant invoice number and
serial number. If you wish, the operating instructions can also be sent to you by
post in paper form against an applicable postage fee.
The devices are only to be used, maintained and serviced by persons familiar
with these operating instructions and in accordance with local regulations
applying to Health & Safety and prevention of accidents.
When used in machines, the measuring unit should be used only when the
machines fulfil the EC-machine guidelines.
as per PED 2014/68/EU
In acc. with Article 4 Paragraph (3), "Sound Engineering Practice", of the PED
2014/68/EU no CE mark.
3. Instrument Inspection
Instruments are inspected before shipping and sent out in perfect condition.
Should damage to a device be visible, we recommend a thorough inspection of
the delivery packaging. In case of damage, please inform your parcel service /
forwarding agent immediately, since they are responsible for damages during
transit.
Scope of delivery:
The standard delivery includes:
•Electronic Mass Flow Meter model: MAS
•Connector

MAS
page 4 MAS K05/0722
4. Regulation Use
Any use of the Electronic Mass Flow Meter, model: MAS, which exceeds the
manufacturer’s specifications, may invalidate its warranty. Therefore, any
resulting damage is not the responsibility of the manufacturer. The user assumes
all risk for such usage.
5. Application
The KOBOLD Electronic Mass Flow Meter, model: MAS, makes very precise
measurements of the Mass Flow Rate of gases in different measuring ranges
from 0 - 10 Ncm³/min up to 0 - 500 NI/min nitrogen. The operation of the meter is
based on the calorimetric principle.
The measuring accuracy is ±1,5% of full scale including linearity over 15 to 25 °C
and 0.3 to 4 bar absolute. Its response time is 800 ms. The typical response time is
6 seconds to display 98% of the full scale value. This can be realised in between
25 to 100% of the full scale value.
Compared to most of the volume flow meters there is no temperature- or
pressure-correction necessary. This means that the MAS is ideally suited for
almost every gas flow application. Typical industrial applications are process
control, laboratory measuring tasks, OEM applications, gas indication panels,
leakage and filter monitoring.
Display rotatable

MAS
MAS K05/0722 page 5
6. Operating Principle
6.1 Measuring principle
The operation of the Mass Flow Meter, model: MAS, is based on the principle of
heat transport (first law of thermodynamic).
The medium flows through the bypass measuring system. Gas enters the MAS
flow body and divides into two flow paths. Part of the flow goes through the
laminar flow bypass the other part flows through the above located measuring
pipe.
Due to the differential pressure between P1 and P2 which is generated by the
laminar flow bypass element a part flow (m1) is separated from the main flow (m)
and guided through the sensor tube.
Two resistance temperature detectors (RTD elements) transferring a constant
amount of heat to the gas stream are mounted on the measuring tube. Under flow
conditions, the gas molecules absorb and transport the heat away from one to the
other coil. The resulting temperature difference is detected by the RTD-sensors
and evaluating by the measuring electronic into an output signal or a display
value. Since the heat is transported by gas molecules, the output signal is linear
proportional to the gas mass flow.

MAS
page 6 MAS K05/0722
7. Mechanical Installation
In order to ensure a successful installation, inlet and outlet tubing or piping should
be in a clean state prior to plumbing your MAS to the system. MAS is applicable
to clean gas only because particles and other foreign matter may pollute the
sensor tube and laminar flow element and cause wrong measurement results. In
case of doubt, we recommend to use filters.
The following working pressures and/or medium temperatures may not be
exceeded:
•10 bar or 50 °C for devices with nylon casing (MAS-1xxx and MAS-2xxx)
•35 bar or 50 °C for devices with stainless steel casing
(MAS-3xxx and MAS-4xxx)
Be sure that the arrow on the side of the transducer points in the direction of flow.
With the nylon casing you must take care not to the turn the thread too far
(maximum 1.5 turns).
Attention! Over-tightening will crack the fittings and shift
calibration.
The preferred mounting position is horizontal. A vertical installation is possible,
but this must be considered during factory-calibration, since one has to count on
a zero-point movement depending on the operating pressure.
Swagelok and NPT screw connections must not be removed from the casing nor
should their position be altered since they form a unit with the laminar element
and could alter the calibration.
Swagelock-connections:
For the first installation of compression fittings, simply insert the tubing into the
fitting. Make sure that the tubing rests firmly on the shoulder of the fitting and that
the nut is hand-tight. Mark the nut at the six o’clock position. While holding the
fitting body steady with a back-up wrench, tighten the nut 11/4 turns. Watching the
mark on the nut, make one complete revolution and continue to the nine o’clock
position. After this, the fitting can be reconnected by tightening with a wrench. Do
not fail to use a back-up wrench or the inlet fitting may be damaged.

MAS
MAS K05/0722 page 7
8. Electrical Connection
The standard MAS is provided with a 9-pin “D” sub type connector located on the
side of the MAS.
Attention! Ensure that the voltage of your installation corresponds
with the voltage of the measuring device.
Attention! A wrong terminal assignment may lead to a damage of the
electronic. If a power supply is connected, do not supply with any
additional voltage on the 9-pin-Sub-D-connector.
When the MAS is configured for a remote display, the display is supplied via the
9-pin “D” connector.
Attention! Please note that opening the device cancels the
guarantee. We therefore recommend that you let such work be done
by KOBOLD Messring GmbH.

MAS
page 8 MAS K05/0722
Pin No. Function
1 No Connection
2 Flow Signal Ground
3 0 to +5 VDC Flow Signal
4 + Power Supply
(12 VDC) *1, *2
5 Remote Display Flow Signal
6 Remote Display Ground
7 Power Supply Ground
8 Analogue output 4 to 20 mA
Ground
9 Analogue output 4 to 20 mA
signal
*1Power supply voltage must be specified
at time of order. Operating a 12 VDC
meter at 24 VDC will cause damage.
Running a 24 VDC meter at 12 VDC will
result in faulty operation.
*2Do not supply + DC power at the “D”
connector while using a power supply at
the DC power jack. Both supplies may be
damaged.
8.1 Power supply
If you use a KOBOLD MAS-5000 or MAS-5015 power pack, insert the jack plug in
the foreseen socket on the Mass Flow Meter MAS. Then simply connect the
power unit to the mains.
If not using a MAS-5000 or MAS-5015 power pack, supply the MAS via the 9-Pin
Sub-D-Connector with a voltage of 12-15 VDC. MAS Flow Meters require a single
+12 to +15 VDC power supply capable of providing a minimum current of 100
mA. The MAS can also be configured for +24 VDC power at 100 mA.
After the power has been switched on the output signal is initially maximum for a
short time (c. 10-20 seconds). It then returns to 0 Volt (or 4 mA, depending on the
model provided). Please note that the warming up period for the MAS should be
about 15 minutes.
After the warming up phase the MAS indicates the measured flow values on the
display.
connector

MAS
MAS K05/0722 page 9
8.2 Output signals
The output signal is obtained from the 9-pin “D” connector. A 0 to 5 VDC output
signal linearly proportional to gas mass flow rate is standard. A 4-20 mA current
loop signal is optionally available.
8.3 Display
KOBOLD Mass Flow Meters, model MAS, for gases are available with an
integrated digital display, a remote digital display and without a digital display.
The decimal point on the version with digital display is set at the factory. It is
always a 3 ½-digit display.
Attention! KOBOLD Messring accepts no liability for any damage,
claims or faults resulting from operation with oxygen. MAS devices
can be manufactured oil and grease free if desired.

MAS
page 10 MAS K05/0722
9. Operation
Pressure- and temperature conditions
The gas flow rate output of your MAS always refers to “standard” conditions of 21 °C
(70 °F) and 760 mm of mercury (1 atmosphere), unless you have specified
otherwise. Make sure that your MAS is always calibrated on the operating
conditions.
Accuracy
The standard accuracy of the MAS is ±1.5% of full scale.
Overranging
If the flow rate exceeds the full scale range listed on your MAS’s front label, the
output signal and digital display (if available) will read a higher value.
Overrange conditions are indicated from the display and/or output by going to a
high level, above the full scale range. After the overrange condition has been
removed, it may take several seconds for the MAS to recover and resume normal
operation. This will not harm the instrument.
Zero and Span Adjustments
The zero and span potentiometers are accessed through marked ports on the
right side of your MAS. The analogue output is factory set and should only be
adjusted, when the zero point is drifting away more than 2% of the maximum
scale value and when you are absolutely sure that no gas is flowing.
Standard 0-5 VDC Output Signal
The standard 0-5 VDC output signal flows from Pin 3 (0-5 VDC Out) through the
load (1 K Ohm minimum) to Pin 7 (Power Common). The figure below is a typical
example of input power and output signal connections.