Kofloc HFM-301 Series User manual

MJ400063H1
Mass Flow Meter
HFM-301series
Mass Flow Controller
HFC-303series

MJ400063H1
The Kofloc HFM-301series mass flow meters and the HFC-303series controller are designed to accurately
measure and control mass flow over the range of 25slm to 1000slm. These instruments are intrinsically linear
and have an accuracy of better than ±1％F.S.（full scale）.
Kofloc mass flow instruments do not require any periodic maintenance under normal operating conditions with
clean gases. No damage will occur from the use of moderate overpressures（~500psi/3.45Mpa）or overflows.
Instruments are normally calibrated with the appropriate standard calibration gas（nitrogen）then a correction
factor is used to adjust the output for the intended gas. Calibrations for other gases, such as oxygen, helium
and argon, are available upon special order.

MJ400063H1
1.1 Specifications
Accuracy
±1％full scale（F.S.）
Repeatable
±0.07％of F.S.
Maximum pressure
500psi ［3.45Mpa］
Maximum pressure
（with high pressure option）
1000psi ［6.9Mpa］
Pressure coefficient
＜0.026％of reading/psi（N2）
Operating temperature
0-60℃in non-condensing environment
Temperature coefficient（ZERO）
Maxim ±0.085％/℃（0-60℃）
Temperature coefficient（SPAN）
Maxim ±0.092％/℃（15-50℃）
Leak integrity
＜1x10-9std.cc/s.
Standard output
0-5VDC （load min 2k Ohms）
Optional output
4-20mA.（load＜600 Ohms）
Power requirements
±（15）VDC＠55mA（meters）
±（15）VDC＠150mA（controller）
Class 2 power 150VA max
Wetted materials
302/304＆316stainless steel, nickle200, Viton
KalrezⓇ（controller only）
Attitude sensitivity of zero
＜±0.25％F.S. for 90℃without re-zeroing
{ N2at 19.7psia（135Kpa）}
Weight
HFM-301；3.5lb（1.6kg）
HFM-303；5.3lb（2.4kg）
Electrical connector
15pin subminiature“D”
Fitting options
HFM-301/HFC-303；1/2“SwagelokⓇ,3/4”SwagelokⓇ

MJ400063H1
1.2 Optional 4-20mA Current Output
An option to the standard 0-5VDC output is the 4-20mA current output that is
proportional to flow. The 4-20mA signal is produced from the 0-5VDC output of the flow
meter. The current loop output is useful for remote applications where pickup noise could
substantially affect the stability of the voltage output.
The current loop signal replaces the voltage output on pin6 of the “D”connector. The
current loop may be returned to either the power supply ground or the -15VDC connection
on the power supply. If the current loop is returned to the supply ground, the load must be
between 0 and 600Ω. If it is returned to the –15VDC, the load must be between 600 and
1200Ω. Failure to meet these conditions will cause failure of the loop transmitter.
2.1 Installation and Operation
Quick Start
1. Insure from circuit mechanical connection are leak free.
2. Insure electrical connections are correct（see label）.
3. Power up.（allow 30 minutes to 1 hour warm-up for best accuracy.）
4. Note the flow signal decays toward zero.
5. Run ~20％flow（~1VDC）through instrument for 5 minutes.
6. Insure zero flow；wait 2 minutes, then zero the instrument.
7. Instrument is ready for operation.
2.2 Power Requirements
The HFM-301 requires +15VDC 55mA, -15VD 50mA. The HFC-303 requires ±15VDC 150mA
for proper operation. The supply voltage should be sufficiently regulated to no more than 50mV
ripple. The supply voltage can very from 14.0 to 16.0VDC.
Surge suppressors are recommended to prevent power spikes reaching the instrument.

MJ400063H1
2.3 Output Signal
The standard output of the flow meter is a 0-5VDC signal proportional to the flow rate. In the
Kofloc power supply the output is routed to the display, and is also available at the terminal on
the rear panel. If a Kofloc supply is not used, the output is available on pin 6 of the “D”
connector. It is recommended that the road resistance be no less that 2ｋΩ. If the optional
4-20mA output is used, the load impedance must be selected in accordance with Section 1.2.
2.4 Mechanical Connection
The flow meter may be mounted in any position as long as the direction of gas flow through the
instrument follows the arrow marked on the bottom of the flow meter case label. The preferred
orientation is with the inlet and outlet fittings in a horizontal plane（if operating with a dense
gas or at high pressures the instrument must be installed horizontally）. When mounted in a
different orientation the instrument should be re-zeroed at zero flow with the system pressurized
to the expected operating pressure.
The smallest of the internal passageways in the 301/303 series is the diameter of the sensor
tube, which are 0.66mm, 0.43mm, 0.36mm, so the instrument requires adequate filtering of the
gas supply to prevent blockage or clogging of the tube.
The pressure regulator and the plumbing upstream must be of sufficient size to minimize
changes in the upstream pressure. When switching from full flow to zero flow, the inlet pressure
of instrument should rise to no more that 30％above the inlet pressure at full flow. In general,
high capacity regulators and large internal diameter plumbing help to make the system more
stable. The pressure drop between the regulator and the instrument due to line resistance
should be minimized.
There are two UNF8-32 threaded holes, 6.4mm deep, located on the bottom of the base that can
be used to secure it to a mounting bracket, if desired. Other holes for special mounting can be
added to the end cap as desired.
It is suggested that all connections be checked for leaks after installation. This can be done by
pressurizing the instrument（do not exceed 500psig unless the flow meter is specifically rated for
higher pressures）and applying a diluted soap solution to the flow connections.

MJ400063H1
2.5 Electrical Connections
If a power supply from Kofloc Instruments is used, installation consists of connecting the
HFM-301 and HFC303 series cable from the “D”connector of the power supply to the “D”
connector of the flow meter / controller .
If a different power supply is used, follow the instructions below when connecting the flow
meter and refer to either table 2.1 for the applicable pin-out. The power supply used must be
bipolar and capable of providing ±15VDC at 55mA for flow meter applications and ±15VDC at
150mA for controllers. These voltages must be referenced to a common ground. One of the
“common”pins must be connected to the AC ground locally. The cable shield （if available）
should be connected to AC ground at the either the power supply end, or the instrument end of
the cable, not to both. Pin6 is the output signal from the flow meter. The standard output will be
0 to 5VDC, where 5VDC is 100％of the rated or full scale flow.
The command（set point）input should be a 0-5VDC signal（or 4-20mA if configured as such）,and
must be free of spikes or other electrical noise, as these would generate false flow commands that
the controller would attempt to follow. The command signal should be referenced to signal
common.
A valve override command is available to the flow controller. Connect the center pin of a single
pole, three-position switch（center off）to the override pin. Connect +15VDC to one end of the
three position switch, and –15VDC to the other end. The valve will be forced full open when
+15VDC is supplied to the override pin, and full closed when –15VDC is applied. When there is
no connection to the pin（the three-position switch is centered）the valve will be in auto control,
and will obey the 0-5VDC commands supplied to command（set-point）input.
Figure 2.1show the 301/303 pin out.

MJ400063H1

MJ400063H1
2.6 Operating
2.6.1 Operating Conditions
For proper operation, the combination of ambient temperature must be such that the flow
meter temperature remains between 0 and 60℃. The301/303 series is intended for use in
non-condensing environments only.
2.6.2. Zero Check
Turn the power supply on if not already energized. Allow for a 1hour warm-up. Stop all flow
through the instrument and wait 2 minutes. Caution：Do not assume that all metering valves
completely shut off the flow. Even a slight leakage will cause an indication on the meter and an
apparent zero shift. For the standard 0-5VDC output, adjust the zero potentiometer located on
the lower inlet side of the flow meter until the meter indicates zero. For the optional 4-20mA
output, adjust the zero potentiometer so that the meter indicates slightly more than 4mA, i.e.
4.03 to 4.05mA. This slight positive adjustment ensures that the 4-20mA current loop
transmitter is not in the cut-off region. The error induced by this adjustment is approximately
0.3％of full scale. This zero should be checked periodically during normal operation. Zero
adjustment is required if there is a change in ambient temperature, or vertical orientation of the
flow orientation of the flow ,meter / controller.
2.6.3 Blending of Gases
In the blending of two gases, it is possible to maintain a fixed ratio of one gas to another. In this
case，the output of one flow controller is used as the reference voltage for set point potentiometer
of a second flow controller. The set point potentiometer then provides a control signal that is
proportional to the output signal of the first flow controller. The set point potentiometer then
provides a control signal that is proportional to the output signal of the first flow controller，and
hence controls the flow rate of the second gas as a percentage of the flow rate of the first gas.
EXAMPLE：Flow controller A has 0-100slpm range with a 5.00V output at full scale. Flow
controller B has 0-10slpm range with a 5.00V output at full scale. If flow controller A is set at
80slpm，its output voltage would be 4.00V（80slpm/100slpm ｘ5.00V＝4.00V）.If the output
signal from flow controller A is connected to the command potentiometer of flow controller B，it
then becomes a variable reference voltage for flow controller B proportional to the flow rate of
flow controller A.
If the set point potentiometer of flow controller B is set at 50％of full scale，and the reference
voltage from flow controller A is 4.00，then the command signal going to flow controller B would
be 2.00V（4.00V x 50.0％＝2.00V）.The flow of gas through flow controller B is then controlled at
4slpm（2.00V／5.00V x 10slpm＝4slpm）.
The ratio of the gases is 20：1（80slpm/4slpm）. The ％mixture of gas A is 95.2（80slpm/84slpm
and the ％mixture of gas B is 4.8％（4slpm/84slpm）.
Should the flow of flow controller A drop to 3.9slpm, hence maintaining the same ratio of the
mixture.（78slpm/100slpm x 5V＝3.90V ｘ50％＝1.95V；1.95V/5.00V x 10slpm＝3.9slpm；
78slpm：3.9slpm＝20：1）

MJ400063H1
3. Overall Function Description
The 301/303 series consists of a sensor, base, shunt, control valve（303）and electronic circuitry.
The sensor is configured to measure gas flow rate from 25-1000slm, depending on the customers
desired overall flow rate. The shunt divides the overall gas flow such that the flow through the
sensor is a precise percentage of the flow through the shunt. The flow through both the sensor
and shunt is laminar. The control valve adjusts the flow so that the sensors measurement
matches the set-point input. The circuit board amplifies the sensor output from the two RTD’s
（Resistive Temperature Detectors）and provides an analog output of either 0-5VDC or 4-20mA.
4. Gas Correction Factors
Most Kofloc flow meters and controllers are calibrated using nitrogen. The correction factors
published by applied to these instruments. To apply the GCF’s（Gas Conversion Factors）, simply
multiply the gas flow reading times the GCF for the process gas in use. For example, to calculate
the actual flow of argon passing through a nitrogen-calibrated meter that reads 20sccm, multiply
the reading times the GCF for argon.
20.000 x 1.3978 ＝27.956
That is, you set the meter to read 14.308sccm.

MJ400063H1
5. Outside Drawing

MJ400063H1
6 Product Warranty
1. The contents of warranty
①Warranty period
The warrant period shall be one year after the shipment.
②Warranty range
If a malfunction of the product you purchased occurs because of our responsible reasons, offer of
substitute or it will be charge-free repaired in our factory. But if a malfunction of the machine
occurs due to the following reasons, even within the warrant period, it becomes the outside for a
warranty.
(a) Malfunctions due to erroneous applications, repairs or remodeling.
(Including the case in which the manufacturing specification differs from the application
conditions.)
(b) Malfunctions due to the falling after the purchase.
(c) Malfunctions caused by natural disasters such as fire, earthquake, water disaster and lightning
stoke, or riots or wars.
(d) Malfunctions caused by mixing-in of foreign matters out of the piping.
(e) Malfunctions caused by the peculiar problems due to combinations with other built in equipment.
In addition, a warranty here means the warranty of the product simple substance of our company.
So the damage induced by failure of the products of our company shall be eliminated from the
object of warranty.
6.1 Coverage
If the failure of the purchased product arises from our fault, the product will be repaired at no
charge. Only the body and our products are covered and no damage caused by the failure will be
compensated.
6.2 Uncovered items
In the following cases, repair will be charged even in the warranty period:
•Failure due to improper use, or unauthorized repair or remodeling.
•Failure due to fall etc. after purchase.
•Failure due to acts of providence including fire, earthquake, flood, stroke of lightning etc.
•Failure due to foreign body from piping.
•Failure due to problems that arise from combination with built-in equipment.

MJ400063H1
URL：http://www.kofloc.co.jp