Aalborg DFC Digital User Manual
OPERATING MANUAL
DFC MASS FLOW
CONTROLLER
Technical Data Sheet No. TD9805M Rev. O
Date of Issue: February 2012
TABLE OF CONTENTS
1. UNPACKING THE DFC 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 DFC 26/36/46 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...........................................................
6. MAINTENANCE...................................................................3
6.1 Introduction........................................................................................
6.2 Flow Path Cleaning..............................................................................
6.2.1 Restrictor Flow Element (RFE).................................................
6.2.2 DFC 26 models.........................................................................
6.2.3 DFC 36/46 models........................................................................
6.2.4 Valve Maintenance ...................................................................
7. CALIBRATION PROCEDURES....................................................
7.1 Flow Calibration...................................................................................
7.2 Calibration of DFC Mass Flow Controllers.......................................
8. TROUBLESHOOTING.............................................................
8.1 Common Conditions...........................................................................
8.2 Technical Assistance............................................................................
8.3 Troubleshooting Guide....................................................................
9. CALIBRATION CONVERSIONS FROM REFERENCE GASES................
1
1
1
1
1
1
2
2
6
6
7
8
11
11
11
11
12
12
12
13
13
13
14
14
14
14
15
15
15
16
17
17
17
18
20
APPENDIX 1 COMPONENT DIAGRAM......................................................
APPENDIX 2 GAS FACTOR TABLE ("K" FACTORS).....................................
APPENDIX 3 DIMENSIONAL DRAWINGS..................................................
APPENDIX 4 SENDING COMMANDS TO THE DFC........................................
APPENDIX 5 SDPROC TABLES: GAS INDEPENDENT VARIABLES................
GAS DEPENDENT VARIABLES...............
APPENDIX 6 WARRANTY...........................................................................
21
25
29
31
37
39
41
1. UNPACKING THE DFC MASS FLOW CONTROLLER
1.1 Inspect Package for External Damage
Your DFC 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 Aalborg7 directly.
When unpacking the instrument please make sure that you have 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 Aalborg7
if you purchased your Mass Flow Controller directly, and request a Return
Authorization Number (RAN). Equipment returned without an RAN will not
be accepted. Aalborg7 reserves the right to charge a fee to the customer for
equipment 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 DFC 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 prevent the introduction of impediments into the
sensor.
1
Caution: It is the users responsibility to determine if the instrument is
appropriate for their OXYGEN application, and for specifying O2
cleaning service if required. Aalborg is not liable for any damage or
personal injury, whatsoever, resulting from the use of this instrument
for oxygen.
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 DFC 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)!
DFC transducers are supplied with standard 1/4 inch (DFC 26 and 36) or 3/8 inch
(DFC 46), 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.
(All DFC's are checked prior to shipment for leak-
age within stated limits. See specifications in this manual.)
2.2 Electrical Connections
DFC 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 DFC models to operate in analog mode. The
Aalborg7 SDPROC accessory Command Modules offer a convenient and compact means to fulfill these needs.
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).
2
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 converter/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.
3
4
FIGURE b-1, WIRING DIAGRAM FOR DFC TRANSDUCERS.
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 - Normally 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, DFC 25 PIN "D" CONNECTOR CONFIGURATION
Important notes:
In general, "D" Connector numbering patterns are standardized. There are, however, some connectors with nonconforming 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 cables 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).
Use of the DFC flow transducer in a manner other than that specified in this manual or in writing from Aalborg7, may impair the protection provided by the equipment.
5
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 geometry 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, DFC model Mass Flow 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 DFC 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.
Free PC Software with Gas Blending and Programmable Flow functions.
4. SPECIFICATIONS
FLOW MEDIUM: Please note that DFC Mass Flow Controllers are designed to
work with clean gases only. Never try to meter or control flow rates of liquids
with any DFC.
CALIBRATIONS: Performed at standard conditions [14.7 psia (1.01 bars) and 70
F
F (21.1 FC)] unless otherwise requested or stated.
ENVIRONMENTAL (PER IEC 664): Installation Level II; Pollution Degree II.
6
4.1 DFC 26/36/46 Mass Flow Controllers
ACCURACY: +
1% of full scale, including linearity for gas temperatures ranging from
59
F
F to 77 FF (15 FC to 25 FC) and pressures of 10 to 60 psia (0.7 to 4.1 bars).
REPEATABILITY: +
0.15% of full scale.
TEMPERATURE COEFFICIENT: 0.1% of full scale/
F
C.
PRESSURE COEFFICIENT: 0.01% of full scale/psi (0.07 bar).
RESPONSE TIME: 1.0 to 2.0 second to within ±2% of set point over 20% to 100%
of full scale.
GAS PRESSURE: 500 psig (34.5 bars) maximum; optimum pressure is 20 psig
(1.4 bars); 25 psig (1.7 bars gauge) for DFC46.
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 DFC26/DFC36, 40 psid for
DFC46.
GAS AND AMBIENT TEMPERATURE: 32
F
F to 122 FF (0 FC to 50 FC). 14 FF to 122
F
F (-10 FC to 50 FC) - Dry gases only.
RELATIVE GAS HUMIDITY: Up to 70%.
MAXIMUM INTERNAL LEAK: 0.5% FS.
LEAK INTEGRITY: 1 x 10-9sccs He maximum to the outside environment.
ATTITUDE SENSITIVITY: 1% shift for a 90 degree rotation from horizontal to verti-
cal; standard calibration is in horizontal position.
OUTPUT SIGNALS: Linear 0-5 VDC (2000 Ω minimum load impedance); 4-20 mA
optional (50-500 Ω loop resistance); 20 mV peak to peak max noise.
Contact your distributor or Aalborg7for optional RS232 or IEEE488 interfaces.
COMMAND SIGNAL: 0-5 VDC (200K Ω input impedance); 4-20 mA optional.
TRANSDUCER INPUT POWER: DFC - +15 +
5% VDC, 450 mA max, 6.75 watts max;
-15 +
5% VDC, 450 mA max; 6.75 watts max;
Power inputs are each protected 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, EPR or KALREZ7 O-rings are optional.
7
Aalborg7 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" (DFC 26/DFC36) or 3/8" (DFC46)
compression fittings standard. 1/8" (DFC26) or 3/8" (DFC26/DFC36)
compression fittings or 1/4" (DFC26/DFC36) VCR7 fittings 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)].
FREE PC SOFTWARE WITH GAS BLENDING AND PROGRAMMABLE FLOW FUNCTIONS.
4.2 CE Compliance
Any model DFC 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
8
FLOW RANGES
TABLE I DFC 26 LOW FLOW MASS FLOW CONTROLLERS*
TABLE II DFC 36 MEDIUM FLOW MASS FLOW CONTROLLERS*
TABLE III DFC 46 HIGH FLOW MASS FLOW CONTROLLERS*
* Flow rates are stated for Nitrogen at STP conditions [i.e. 70 FF (21.1 FC) at 1 atm].
For other gases use the K factor as a multiplier from APPENDIX 2.
9
CODE scc/min [N2]
CODE
std liters/min [N
2
]
01 0 to 10 07 0 to 1
02 0 to 20 08 0 to 2
03
0 to 50
09
0 to 5
04 0 to 100 10
0 to 10
05
0 to 200
06 0 to 500
CODE standard liters/min [N2]
11
0 to 15
30 20
31 30
32 40
33 50
CODE standard liters/min [N2]
40 60
41 80
42 100
TABLE IV PRESSURE DROPS
TABLE V APPROXIMATE WEIGHTS
10
MODEL
FLOW RATE
[std liters/min]
MAXIMUM PRESSURE DROP
[mm H2O] [psid]
[mbar]
DFC 26
up to 10
720 1.06 75
DFC 36
15 2630 3.87 266
20
1360 2.00 138
30
2380 3.50 241
40
3740
5.50
379
50 5440 8.00 551
DFC 46
60
7480 11.00 758
100
12850 18.89 1302
MODEL WEIGHT SHIPPING WEIGHT
DFC 26 transmitter 2.20 lbs (1.00 kg) 3.70 lbs (1.68 kg)
DFC 36/46 transmitter 2.84 lbs (1.29 kg) 4.34 lbs (1.97 kg)
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 DFC transducer, the flow output signal will be indicating a higher than usual output. This is indication that the DFC 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.
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 observed 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
DFC transducer. The output flow signal is also available 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 Aalborg7.
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.
11
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.
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