Dwyer DMF User Manual
Technical Data Sheet No. TD9805M Rev. L
Date of issue: September, 2006
OPERATING MANUAL
FOR DMF
DIGITAL MASS FLOW CONTROLLERS
P.O. Box 373
Michigan City, IN 46361 USA
Phone: (219) 879 8000
FAX: (219) 879 9057
E mail: info@dwyer.com
Internet: http://www.dwyer-inst.com
TABLE OF CONTENTS
1. UNPACKING THE DMF MASS FLOW CONTROLLER........................
1.1 Inspect Package for External Damage..............................................
1.2 Unpack the Mass Flow Controller.......................................................
1.3 Returning Merchandise for Repair.....................................................
2. INSTALLATION....................................................................
2.1 Primary Gas Connections.................................................................
2.2 Electrical Connections......................................................................
2.3 Communication Parameters and Connections................................
3. PRINCIPLE OF OPERATION..................................................
4. SPECIFICATIONS..................................................................
4.1 DMF 41 Mass Flow Controllers.........................................................
4.2 CE Compliance................................................................................
5. OPERATING INSTRUCTIONS.....................................................
5.1 Preparation and Warm Up................................................................
5.2 Flow Signal Output Readings..............................................................
5.3 Swamping Condition...........................................................................
5.4 Set Point Reference Signal .............................................................
5.5 Valve OFF Control ..........................................................................
5.6 Valve Open/Purge ............................................................................
5.7 Analog Interface Configuration...........................................................
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6. MAINTENANCE...................................................................3
6.1 Introduction........................................................................................
6.2 Flow Path Cleaning..............................................................................
6.2.1 Restrictor Flow Element (RFE).................................................
6.2.2 DMF 41401-41411 models..........................................................
6.2.3 DMF 41431-41842 models..........................................................
6.2.4 Valve Maintenance ...................................................................
7. CALIBRATION PROCEDURES....................................................
7.1 Flow Calibration...................................................................................
7.2 Calibration of DMF Mass Flow Controllers.......................................
8. TROUBLESHOOTING.............................................................
8.1 Common Conditions...........................................................................
8.2 Technical Assistance............................................................................
8.3 Troubleshooting Guide....................................................................
9. CALIBRATION CONVERSIONS FROM REFERENCE GASES................
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APPENDIX 1 COMPONENT DIAGRAM......................................................
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APPENDIX 2 GAS FACTOR TABLE ("K" FACTORS).....................................
APPENDIX 3 DIMENSIONAL DRAWINGS..................................................
APPENDIX 4 SENDING COMMANDS TO THE DMF........................................
APPENDIX 5 SDPROC TABLES: GAS DEPENDENT VARIABLES....................
GAS INDEPENDENT VARIABLES...............
APPENDIX 6 WARRANTY...........................................................................
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1. UNPACKING THE DMF MASS FLOW CONTROLLER
1.1 Inspect Package for External Damage
Your DMF Mass Flow Controller was carefully packed in a sturdy cardboard carton, with anti-static cushioning materials to withstand shipping shock. Upon
receipt, inspect the package for possible external damage. In case of external
damage to the package contact the shipping company immediately.
1.2 Unpack the Mass Flow Controller
Open the carton carefully from the top and inspect for any sign of concealed shipping damage. In addition to contacting the shipping carrier please forward a copy
of any damage report to your distributor or Dwyer directly.
When unpacking the instrument please make sure that you hav e all the items indicated on the Packing List.Please report any shortages promptly.
1.3 Returning Merchandise for Repair
Please contact the customer service representative of your distributor or Dwyer if
you purchased your Mass Flow Controller directly, and request a Return
Authorization Number (RAN). Equipment returned without an RAN will not
be accepted. Dwyer reserves the right to charge a fee to the customer for equip-
ment returned under warranty claims if the instruments are tested to be free from
warrantied defects.
Shipping charges are borne by the customer.Meters returned "collect" will not be
accepted!
It is mandatory that any equipment returned for servicing be purged and neutralized of any dangerous contents including but not limited to toxic, bacterially infectious, corrosive or radioactive substances. No work shall be performed on a
returned product unless the customer submits a fully executed, signed SAFETY
CERTIFICATE. Please request form from the Service Manager.
2. INSTALLATION
2.1 Primary Gas Connections
Please note that the DMF Mass Flow Controller will not operate with liquids.Only
clean gases are allowed to be introduced into the instrument. If gases are contaminated they must be filtered to prev ent the introduction of impediments into the
sensor.
Caution: DMF transducers should not be used for monitoring
OXYGEN gas unless specifically cleaned and prepared for such
application. For more information, contact your distributor or Dwyer.
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Attitude sensitivity of the Mass Flow Controller is +15F. This means that the gas flow
path of the Flow Controller must be horizontal within those stated limits. Should
there be need for a different orientation of the meter, re-calibration may be necessary.It is also preferable to install the DMF transducer in a stable environment, free
of frequent and sudden temperature changes, high moisture, and drafts.
Prior to connecting gas lines inspect all parts of the piping system including ferrules and fittings for dust or other contaminants.
Be sure to observe the direction of gas flow as indicated by the arrow on the front
of the meter when connecting the gas system to be monitored.
Insert tubing into the compression fittings until the ends of the properly sized tubings home flush against the shoulders of the fittings. Compression fittings are to
be tightened according to the manufacturer's instructions to one and one quarter
turns. Avoid over tightening which will seriously damage the Restrictor Flow
Elements (RFE's)!
DMF transducers are supplied with standard 1/4 inch (DMF 41401-41433) or 3/8
inch (DMF 41842), or optional 1/8 inch inlet and outlet compression fittings which
should not be removed unless the meter is being cleaned or calibrated for a new
flow range.
Using a Helium Leak Detector or other equivalent method perform a thorough
leak test of the entire system.
age within stated limits. See specifications in this manual.)
(All DMF's are checked prior to shipment for leak-
2.2 Electrical Connections
DMF transducers require a +15VDC and -15VDC power supply to operate.
Additionally, a readout panel meter, digital multimeter, or other equivalent device
is required to observe the flow signal in analog mode. A variable analog 0-5VDC
reference input is required for DMF models to operate in analog mode. The Dwyer
SDPROC accessory Command Modules offer a convenient and compact means
to fulfill these needs.
DMF is supplied with a 25 pin "D" connector. Pin diagram is presented in figure b-2.
2.3 Communication Parameters and Connections
Baud rate: 9600 baud Stop bit: 1
Data bits: 8 Parity: NON
RS-232 option: Crossover connection has to be established:
Pin 11 (TX) of the “D” connector has to be connected to RX
(pin 2 on the DB9 connector).
Pin 24 (RX) of the “D” connector has to be connected to TX
(pin 3 on the DB9 connector).
Pin 20 (Common) of the “D” connector has to be connected
to GND (pin 5 on the DB9 connector).
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RS-485 option:
The RS485 converter/adapter has to be configured for:multidrop, 2 wire, half duplex
mode.The transmitter circuit has to be enabled by TD or RTS (depending on which
is available on the con v erter/adapter).Settings for the receiver circuit usually should
follow the selection made for the transmitter circuit in order to eliminate Echo.
Pin 11 (-) of the “D” connector has to be connected to
T- or R- on the RS-485 converter/adapter.
Pin 24 (+) of the “D” connector has to be connected to
T+ or R+ on the RS-485 converter/adapter.
Pin 20 (Common) of the “D” connector has to be connected
to GND on the RS-485 converter/adapter.
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FIGURE b-1, WIRING DIAGRAM FOR DMF TRANSDUCERS.
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PIN FUNCTION
1 +15 VDC Power Supply
2 0-5 VDC Flow Signal (4-20mA Option)
3 0-5 VDC Set Point Input (4-20mA Option)
4 Force Valve Open Control
5 Force Valve Closed Control
6 (Reserved)
7 (Reserved)
8 Relay No. 1 - Common Contact
9 Relay No. 1 - Nor mally Open Contact
10 Relay No.2 - Normally Closed Contact
11 RS485 (-) (Optional RS232 TX)
12 (No Connection)
13 Chassis Ground
14 -15 VDC Power Supply
15 Common, Signal Ground For Pin 2
16 Common, Signal Ground For Pin 3
17 (Optional) RS232 Common
18 Common, Power Supply
19 Common
20 Common
21 Relay No.1 - Normally Closed Contact
22 Relay No.2 - Common Contact
23 Relay No.2 - Normally Open Contact
24 RS485 (+) (Optional RS232 RX)
25 Return for Pin 2 (Optional 4-20 mA Only)
FIGURE b-2, DMF 25 PIN "D" CONNECTOR CONFIGURATION
Important notes:
In general, "D" Connector numbering patterns are standardized.There are, however , some connectors with nonconf orming patterns and the numbering sequence
on your mating connector may or may not coincide with the numbering sequence
shown in our pin configuration table above. It is imperative that you match the
appropriate wires in accordance with the correct sequence regardless of the particular numbers displayed on your mating connector.
Make sure power is OFF when connecting or disconnecting any cab les in the system.
The (+) and (-) power inputs are each protected by a 500mA M (medium time-lag)
resettable fuse. If a shorting condition or polarity reversal occurs, the fuse will cut
power to the flow transducer circuit. Disconnect the power to the unit, remove the
faulty condition, and reconnect the power. The fuse will reset once the faulty condition has been removed.
Cable length may not exceed 9.5 feet (3 meters).
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Use of the DMF flow transducer in a manner other than that specified in this man-
F
ual or in writing from Dwyer, ma y impair the protection provided b y the equipment.
3. PRINCIPLE OF OPERATION
The stream of gas entering the Mass Flow transducer is split by shunting a small
portion of the flow through a capillary stainless steel sensor tube. The remainder
of the gas flows through the primary flow conduit. The geometr y of the primary
conduit and the sensor tube are designed to ensure laminar flow in each branch.
According to principles of fluid dynamics the flow rates of a gas in the two laminar flow conduits are proportional to one another.Therefore, the flow rates measured in the sensor tube are directly proportional to the total flow through the transducer.
In order to sense the flow in the sensor tube, heat flux is introduced at two sections of the sensor tube by means of precision wound heater sensor coils.Heat is
transferred through the thin wall of the sensor tube to the gas flowing inside. As
gas flow takes place heat is carried by the gas stream from the upstream coil to
the downstream coil windings. The resultant temperature dependent resistance
differential is detected by the electronic control circuit.The measured gradient at
the sensor windings is linearly proportional to the instantaneous rate of flow taking place.
An output signal is generated that is a function of the amount of heat carried by
the gases to indicate mass molecular based flow rates.
Additionally , DMF model Mass Flo w Controllers incorporate a microprocessor and
non-volatile memory that stores all calibration factors and directly controls a proportionating solenoid valve. The digital closed loop control system of the DMF
continuously compares the mass flow output with the selected flow rate.
Deviations from the set point are corrected by compensating valve adjustments,
thus maintaining the desired flow parameters with a high degree of accuracy.
4. SPECIFICATIONS
FLOW MEDIUM: Please note that DMF Mass Flow Controllers are
designed to work with clean gases only. Never try to
meter or control flow rates of liquids with any DMF.
CALIBRATIONS: Performed at standard conditions [14.7 psia
(1.01 bars) and 70
requested or stated.
ENVIRONMENTAL (PER IEC 664):
Installation Level II;Pollution Degree II.
F (21.1FC)] unless otherwise
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4.1 DMF Mass Flow Controllers
F
F
F
ACCURACY: +
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F to 77FF (15FC to 25FC) and pressures of 10 to 60 psia (0.7 to 4.1 bars).
REPEATABILITY: +
TEMPERATURE COEFFICIENT: 0.1% of full scale/
1% of full scale, including linearity for gas temperatures ranging from
0.15% of full scale.
C.
PRESSURE COEFFICIENT: 0.01% of full scale/psi (0.07 bar).
RESPONSE TIME: DMF 41401-41411: 300ms time constant; approximately 1
second to within +
2% of set flow rate for 25% to 100% of full scale flow.
DMF41431-41842: 600ms time constant; approximately 2
seconds to within +
2% of set flow rate for 25% to 100% of full scale flow.
GAS PRESSURE: 500 psig (34.5 bars) maximum; optimum pressure is 20 psig (1.4
bars); 25 psig (1.7 bars gauge) for DMF 41842.
DIFFERENTIAL PRESSURES REQUIRED: 5 to 50 psig (0.35 to 3.34 bars) differential
pressures. Optimum differential pressure is 25 psid (1.7 bars). See Table IV for
pressure drops associated with various models and flow rates.
MAXIMUM PRESSURE DIFFERENTIAL: 50 psid for DMF 41401-41433, 40 psid for
DMF 41842.
GAS AND AMBIENT TEMPERATURE: 41
F to 122FF (5FC to 50FC).
RELATIVE GAS HUMIDITY: Up to 70%.
LEAK INTEGRITY: 1 x 10
-9
sccs He maximum to the outside environment.
ATTITUDE SENSITIVITY: 1% shift for a 90 degree rotation from horizontal to vertical; standard calibration is in horizontal position.
OUTPUT SIGNALS: Linear 0-5 VDC (2000 : minimum load impedance); 4-20 mA
optional (50-500 :loop resistance); 20 mV peak to peak max noise.
Contact your distributor or Dwyer for optional RS232 or IEEE488 interfaces.
COMMAND SIGNAL: 0-5 VDC (200K :input impedance); 4-20 mA optional.
TRANSDUCER INPUT POWER: DMF - +15 +
max; -15 +
5% VDC, 450 mA max; 6.75 watts max; Power inputs are each pro-
5% VDC, 450 mA max, 6.75 watts
tected by a 500mA M (medium time-lag) resettable fuse, and an inverse shunt
rectifier diode for polarity protection.
WETTED MATERIALS: 316 stainless steel, 416 stainless steel, VITON7 O-rings;
BUNA-N7, NEOPRENE7 or KALREZ7 O-rings are optional.
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Dwyer makes no expressed or implied guarantees of corrosion resistance of
mass flow meters as pertains to different flow media reacting with components of
meters. It is the customers' sole responsibility to select the model suitable for a
particular gas based on the fluid contacting (wetted) materials offered in the different models.
INLET AND OUTLET CONNECTIONS: 1/4" (DMF 41401-41433) (DMF 41842) or 3/8"
compression fittings standard; 1/8" or 3/8" compression fittings and 1/4" VCR7 fit-
tings are optional.
TRANSDUCER INTERFACE CABLE: Flat cable with 25-pin "D" connectors on the
ends is standard.Optional shielded cable is available with male/female 25-pin "D"
connector ends. [Cable length may not exceed 9.5 feet (3 meters)]
4.2 CE Compliance
Any model DMF bearing a CE marking on it, is in compliance with the below
stated test standards currently accepted.
EMC Compliance with 89/336/EEC as amended;
Emission Standard: EN 55011:1991, Group 1, Class A
Immunity Standard: EN 55082-1:1992
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FLOW RANGES
TABLE I DMF 41 LOW FLOW MASS FLOW CONTROLLERS*
CODE
401 0 to 10 07 0 to 1
402 0 to 20 08 0 to 2
403 0 to 50 09 0 to 5
404 0 to 100 10 0 to 10
405 0 to 200
406 0 to 500
scc/min [N2]
CODE
std liters/min [N
TABLE II DMF 36 MEDIUM FLOW MASS FLOW CONTROLLERS*
CODE standard liters/min [N2]
11 0 to 15
30 20
31 30
32 40
33 50
]
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TABLE III DMF 46 HIGH FLOW MASS FLOW CONTROLLERS*
CODE standard liters/min [N2]
40 60
41 80
42 100
* Flow rates are stated for Nitrogen at STP conditions [i.e. 70FF (21.1FC) at 1 atm].
For other gases use the K factor as a multiplier from APPENDIX 2.
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TABLE IV PRESSURE DROPS
MODEL
DMF 41411 up to 10 720 1.06 75
DMF 41431
DMF 41433 50 5440 8.00 551
DMF 41842 100 12850 18.89 1302
FLOW RATE
[std liters/min]
15 2630 3.87 266
30 2380 3.50 241
MAXIMUM PRESSURE DROP
[mm H2O] [psid] [mbar]
TABLE V APPROXIMATE WEIGHTS
MODEL WEIGHT SHIPPING WEIGHT
DMF 41401-41411 controller 2.20 lbs (1.00 kg) 3.70 lbs (1.68 kg)
DMF 41431-41842 controller 2.84 lbs (1.29 kg) 4.34 lbs (1.97 kg)
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5. OPERATING INSTRUCTIONS
5.1 Preparation and Warm Up
It is assumed that the Mass Flow Controller or Controller has been correctly
installed and thoroughly leak tested as described in section (2). Make sure the
flow source is OFF. Power up the transducer using your own power supply (or
switch the POWER switch to the ON position at the front panel of your SDPROC
Command Module). Allow the Mass Flow Meter or Controller to warm-up for a
minimum of 15 minutes.
During initial powering of the DMF transducer, the flow output signal will be indicating a higher than usual output. This is indication that the DMF transducer has
not yet attained it's minimum operating temperature. This condition will automatically cancel within a few minutes and the transducer should eventually zero.
Caution: If the valve is left in the AUTO (control) or OPEN mode for an
extended period of time, it may become warm or even hot to the touch.
Use care in avoiding direct contact with the valve during operation.
5.2 Flow Signal Output Readings
The flow signal output can be viewed on the panel meter, digital multimeter, or
other display device used as shown in figure b-1.
When using the accessory SDPROC Command Module the flow rate will appear
on the display at the front panel.The obser ved reading is a 0 to 100% indication
(direct engineering units are optional). [If using a multichannel readout, be sure
that the CHANNEL selector switch is set to the correct channel.]
Analog output flow signals of 0 to 5 VDC or optional 4 to 20 mA are attained at
the appropriate pins the 25-pin "D" connector (see Figure b-2) on the side of the
DMF transducer.The output flow signal is also a v ailab le at the DATA connector on
the rear panel of the SDPROC Command Module.
Meter signal output is linearly proportional to the mass molecular flow rate of the
gas being metered. The full scale range and gas for which your meter has been
calibrated are shown on the flow transducer's front label.
For information on the RS485 or optional RS232 interfaces please contact your
distributor or Dwyer.
5.3 Swamping Condition
If a flow of more than 10% above the maximum flow rate of the Mass Flow
Controller is taking place, a condition known as "swamping" may occur.Readings
of a "swamped" meter cannot be assumed to be either accurate or linear. Flow
must be restored to below 110% of maximum meter range. Once flow rates are
lowered to within calibrated range, the swamping condition will end. Operation of
the meter above 110% of maximum calibrated flow may increase recovery time.
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