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GAS MASS FLOW CONTROLLERS
With RS485 Standard and Alarm Functions
For Clean Gases
FMA6500ST Series
Standard
U Digital and Analog
Modes Operate
Simultaneously
U Programmable Flow
Configurations
U RS485 Standard,
Multi-Drop Capability
of Up to 256 units
U Stores Calibration Data
for Up to 10 Gases
U Totalizer Indicates
Total Gas Quantity
U Alarm Limits for High
and Low Gas Flow
U Conversion Factors
for Up to 256 Gases
U Autotune Function
for Optimum
Control Response
U Self Diagnostic Tests
Microprocessor driven digital flow
controllers allow one to program,
record, and analyze flow rates of
various gases with a computer via
an RS485 interface (optional
RS232 is available).
Controllers can be programmed for
various control functions including,
flow setpoint, totalizer, stop totalizer,
read totalizer, totalizer from preset
flow, stop at preset total, auto zero,
and more.
Principles of Operation
Metered gases are divided into two
laminar flow paths, one through the
primary flow conduit, and the other
through a capillary sensor tube.
Both flow conduits are designed
to ensure laminar flow, therefore,
the ratio of their flow rates remains
constant. Two precision temperature
sensing windings on the sensor
tube are heated, and when flow
takes place, gas carries heat from
the upstream to the downstream
windings. The resultant temperature
differential is proportional to the
change in resistance of the sensor
windings.
A Wheatstone bridge
design is used to monitor the
temperature dependent resistance
gradient on the sensor windings
which is linearly proportional to the
instantaneous rate of flow. The
output of the Wheatstone bridge
is converted to digital format with
a 12-Bit Adc (analog to digital
converter).
An on-board microprocessor and
nonvolatile memory store all
calibration factors and directly
control a proportional
electromagnetic valve. The digital
D-XX
FMA6502ST shown
smaller than actual size.
closed loop control system
continuously compares the mass
flow output with the selected flow
rate. Deviations from the setpoint are
corrected by compensating valve
adjustments, with PID algorithm,
thus maintaining the desired flow
parameters with a high degree of
accuracy. Output signals of
0 to 5 Vdc or 4 to 20 mA are
generated indicating mass molecular
based flow rates of the metered gas.
Interface
The digital interface operates
via RS485 (optional RS232) and
provides access to applicable
internal data including: flow setpoint, actual flow, zero adjustments,
and linearization table adjustments.
The analog interface provides 0 to
5 Vdc, 0 to 10 Vdc and 4 to 20 mA
inputs and outputs.
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Auto Zero
The FMA6500ST automatically
nulls the sensor zero offset
whenever the flow setpoint is below
2% FS. To accommodate this feature
the control valve must fully close
under that condition. Provisions are
made to either disable, force, or store
thecurrent auto zero via digital
commands.
Totalizer
The firmware for the FMA6500ST
provides functions to register total gas
quantity. The total mass of gas is
calculated by integrating the actual
gas flow rate with respect to time.
Digital interface commands are
provided to: set the totalizer to zero,
start/stop totalizing the flow, read the
totalizer, start the totalizer at a preset
flow, and stop the flow at a preset
total.
Multi-Gas Calibration Option
The FMA6500ST is capable of
storing primary calibration data for
up to 10 gases. This feature allows
the same FMA6500ST to be calibrated
for multiple gases while maintaining
the rated accuracy on each.
Standard 10-Point NIST
Calibration
Optional up to 9 additional 10-point
calibration may be ordered at an
additional cost per gas.
Conversion Factors
Conversion factors for up to 256 gases
are stored in the FMA6500ST.
Conversion factors may be applied
to any of the ten gas calibrations via
digital interface commands.
Flow Alarms
High and Low gas flow ALARM
limits are programmed using the
digital interface. Alarm conditions
are reported via the digital interface
or can activate the contact closure
outputs.
Programmable Flow
OMEGA® software supports
programmable flow modes, allowing
execution of custom programming
of up to ten steps. Various flow
configurations include ramping,
linearized increasing, and
decreasing modes.
Autotune
The autotune function allows the
FMA6500ST to automatically
optimize control response for the gas
under actual process conditions.
During the autotune process, the
instrument adjusts PID gains for
optimum step response and determine key control valve characteristics
(only available on units with less than
80 L/min maximum flow).
Contact Closure
Two sets of dry contact relay
outputs are provided to actuate
user supplied equipment. These are
programmable via the digital interface
such that the relays can be made to
switch when a specified event occurs
(e.g. when a low or high flow alarm
limit is exceeded or when the totalizer
reaches a specified value).
Valve Override
Means are provided to force the
control valve fully open (purge) or
fully closed via either the analog or
digital interfaces.
Self Diagnostics
Whenever power is first applied,
the FMA6500ST runs a series
of self diagnostic tests to
ensure that it is in optimum
working condition.
Engineering Units
The flow setpoint, measured gas
flow and associated totalizer data
is scaled directly in engineering
units via digital interface commands. The following units of
measure are supported: % of
FS, mL/min, mL/hr, scfm, scfh, sL/
min, sL/hr, lbs/hr, lbs/min, and one
user defined unit of measure.
Leak Integrity
1 x 10-9 smL/sec of helium
maximum to the outside
environment.
Balanced Power Supply
The FMA6500ST operates on
±15 Vdc. The current requirements
for the positive and negative power
supplies are balanced such that
the current in the power supply
common connection is minimized.
Maximum power consumption is
13.5 watts at ±15 Vdc.
SPECIFICATIONS
Accuracy (including linearity):
15 to 25°C (59 to 77°F) and 0.7 to 4 bar
(10 to 60 psia): ±1% of FS, 0 to 50°C
(32 to 122°F) and 0.3 to 10 bar (5 to
150 psia): ±2% of FS, ±1% of FS at a
specific temperature and pressure
with special calibration
Repeatability: ±0.15% FS
Turndown Ratio: 50:1
Response Time: 0.6 to 1.0 s to within
±2% of setpoint over 20% to 100% FS
Temperature Coefficient:
0.05% of full scale/°C or better
Pressure Coefficient: 0.01% FS/psi
(0.07 bar) or better
Leak Integrity:
-9
1 x 10
smL/sec Helium maximum to the
outside environment
Optimum Gas Pressure:
1.73 bar (25 psig)
D-XX
FMA6502ST, shown
smaller than actual size.
Maximum Gas Pressure: 34.5 bar
(500 psig)
Maximum Diff. Pressure: 3.4 bar (50
psig) for up to 10 LPM, 2.8 bar (40 psig)
for 15 LPM and greater
Gas and Ambient Temperature:
5 to 50°C (41 to 122°F)
Output Signals: Linear 0 to 5 Vdc
(2000 Ω min load impedance);
0 to 10 Vdc (4000 Ω min impedance);
4 to 20 mA optional (0 to 500 Ω loop
resistance)
Communication Interface:
RS485, standard; RS232, optional
Transducer Input Power:
±15 Vdc, 450 mA maximum
Wetted Parts: 316 stainless steel,
416 stainless steel, FKM
Neoprene or Perfluoroelastomer
O-rings optional
Connections: Standard ¹⁄₄"
compression fittings up to 30 LPM
models; for 60 LPM models and greater:
³⁄₈" compression fittings
Circuit Protection:
Circuit boards have built-in polarity
reversal protection; resettable fuses
provide power input protection
Calibration Options:
Standard 10-point NIST calibration
optional up to 9 additional 10-point
calibrations may be ordered for a
additional cost per gas
O-rings
D
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FMA6500ST Controller Dimensions 15 LPM and Greater FMA6500ST Controller Dimensions Up to 10 LPM
25-Pin
D-Connector Male
25-Pin
D-Connector Male
157.1 (6.19)
12.7 (0.50)
15.9 (0.63)
47.6 (1.88)
* For High-Flow
Mass Flow Controllers
167.0 (6.58)
15.9 (0.63)
68.3 (2.69)
FLOW
92.1 (3.63)
143.5 (5.65)
*149.1 (5.87)
10.3 (0.41)
12.7 (0.50)
38.1 (1.50)
6-32-2B
17.5 (0.69)
Dimensions: mm (inch) Dimensions: mm (inch)
Standard Cable (Supplied with FMA6500ST) FMA65-C
25 Pins
FMA6500
3
Power
Supply
1.8 (6)
3
Computer
Communication
FMA65-C15
82.6 (3.25)
133.8 (5.27)
6-32-2B
74.3 (2.93)
4.0 (0.16)
FPW-D15 power supply,
sold separately.
Dimensions: m (ft)
17.5 (0.69)
FMA6500
FMA65PWA
FMA6500
FMA65PWC
FMA6500
25 Pins
1.8 (6)
25 Pins
1.8 (6)
25 Pins
1.8 (6)
Transformer
Transformer
15 Pins
3
9
3
3
3
3
Command
Module
Proc
Computer
Communication
Analog Setpoint
Analog Output
Purge
Close
Relay
Other See Manual
Computer
Communication
Power
110/230/240 V
Computer
Communication
Power
110/230/240 V
Dimensions: m (ft)
Dimensions: m (ft)
Dimensions: m (ft)
D-XX
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To Order
Model No. Maximum Flowrate** Compression Fitting Maximum Pressure Drop (psid)
FMA6502ST 10 SCCM ¹⁄₄" 1.06
FMA6504ST 20 SCCM ¹⁄₄" 1.06
FMA6506ST 50 SCCM ¹⁄₄" 1.06
FMA6508ST 100 SCCM ¹⁄₄" 1.06
FMA6510ST 200 SCCM ¹⁄₄" 1.06
FMA6512ST 500 SCCM ¹⁄₄" 1.06
FMA6514ST 1 SLM ¹⁄₄" 1.06
FMA6516ST 2 SLM ¹⁄₄" 1.06
FMA6518ST 5 SLM ¹⁄₄" 1.06
FMA6520ST 10 SLM ¹⁄₄" 3.87
FMA6523ST 15 SLM ¹⁄₄" 2.00
FMA6524ST 20 SLM ¹⁄₄" 3.50
FMA6526ST 30 SLM ¹⁄₄" 8.00
FMA6528ST 50 SLM ¹⁄₄" 8.00
FMA6540ST 60 SLM ³⁄₈" 18.9
FMA6541ST 80 SLM ³⁄₈" 18.9
FMA6542ST 100 SLM ³⁄₈" 18.9
Accessories
Model No. Description
FMA65-C Replacement cable 25 pin D-conn with 1.8 m (6') wire, branch
FMA65PWC Power supply with 25 pin female D-conn 110 Vac (±15 Vdc)
FMA65PWA
FMA65EPWC European power supply with 25 pin female D-conn 230 Vac
FMA65UKPWC UK power supply with 25 pin female D-conn 230 Vac (±15 Vdc)
FMA65-C15 25 pin D-conn with 1.8 m (6') wire to 15 pin DM, branch 1.8 m
FMA65-CAL-(*) 10-point NIST calibration per gas; specify up to 9 gases
Comes complete with operator’s manual, software, cable (FMA65-C), and NIST certificate.
Power supply sold separately.
Specify gas or gases and inlet/outlet pressure. Calibrations done at ambient [20ºC (70ºF)]
*
temperature only.
Flow ranges specified are for nitrogen or air at 20 psig inlet (up to 50 SLM) or 25 psig inlet
**
(60 to 100 SLM units) and 0 psig outlet, see above ordering chart.
For RS232 communications (replaces RS485), add suffix “-RS232” to model number, no
additional cost.
For 4 to 20 mA output (replaces 0 to 5V), add suffix “-I” to model number, no additional cost.
For Perfluoroelastomer O-rings (replaces FKM O-rings), add suffix “-K” to model number,
for additional cost.
Ordering Examples: FMA6512ST, mass flow controller, and FMA65PWC power supply.
FMA6542ST, mass flow controller, and FMA65PWC power supply.
to power supply
branch 1.8 m (6') wire to computer port, stripped
Power supply with 25 pin female D-conn 110 Vac (±15 Vdc)
branch 1.8 m (6') wire to analog interface
(±15 Vdc) branch 1.8 m (6') wire to computer port, stripped
branch 1.8 m (6') wire to computer port, stripped
(6'), wire to computer port, stripped
(specify primary gas on FMA6500, inlet/outlet,
and temperature)
D
FMA6502ST
shown smaller
than actual size.
D-XX
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