Note3) Zero adjustment error alarms regardless of the “Enable” / “Disable” of the alarm.
·
If a zero-set input of longer than 5seconds is input the Baud rate will be set to 9600bps and other
communication protocols will be returned to initial value (factory shipped value).
9. Operation
(1) Procedure
1) This product is packed in a clean room before shipment. Please break the
seals in a clean room after taking it out of its box.
2) Check the gas type and flow rate, and check the direction of the gas flow
and the MFC before installation.
3) Please set up the high temperature part in a thermostatic bath. When
using a heater, set up the heater in a way of not causing temperature
distribution (When controlling the liquid by vapor pressure, set the
temperature of main body higher than the liquid temperature.
Recommended time: above 20 ºC)
4) Check for gas leaks from the tubing with a helium (He) leak detector.
5) Connect the interface connectors according to the Connector tale.
6) Power requirements are +15VDC: 100mA and -15VDC: 200mA. Check
the voltage, polarity, and capacitance of the power supply voltage.
7) This product consists of a control part and a high temperature part. Be sure
to connect the control part and the high temperature part of the same serial
number before supplying power to the control part. Incorrect procedure
may cause damage to internal equipment. Also, please supply the power
supply, warm up the high temperature part to the specified temperature
range and warm up for 2 hours or more (Please carry out until the main
body temperature reaches the same temperature as the ambient
temperature).
8) Adjust the zero point by pressing the zero adjustment, switch located on
the top of the MFC. Before zero-point adjustment, check that gas is not
being supplied and the device was warmed up for 30 minutes or more in
order to ensure sensor stability.
9) Input the flow rate setting signal and supply gas with required differential
pressure to the MFC. The MFC will begin to control the gas flow in
proportion to the preset voltage. Full-scale voltage is 5VDC. Maximum
input voltage is ±15.5VDC.
10) When the output flow rate signal is used, the tolerance voltage of the
external device should be more than ±15.5VDC. When it’s connected the
output valve may be within the range of the maximum voltage ±15.5VDC.
11) Complete shut off cannot be achieved with the mass flow controller. If
complete shut off is desired, a shut-off valve should be installed.
12) When a highly reactive gas is used, thoroughly purge all foreign matter
from the tubing and the MFC before operation.
13) When contaminated gas is used, install a filter at the equipment inlet.
14) Use the MFC within the range of the operating temperature, and keep it
at the same temperature with the gas. If usedin any environment that does
not meet the above-mentioned requirements, the flow rate cannot be
measured accurately and the device may fail.
15) Donotswitchthepowersupplyonandoffwithinonesecond.Itmaycausefailure.
(2) Valve control signal
The MC features a forced valve open/close input function.
The connector pin No.1 is used to input the internal valve open/close signal.
By inputting this signal, a forced opening/closing of the internal valve can be
performed without depending on the value of the flow rate preset signal.
When +15VDC is input: fully open
When –15VDC is input: fully closed.
(3) Conversion factor
TheMFC ispresetbased on thekind of gas and the flow rate. If a gasthat is not
specified issupplied, thecontrolled flow rate may be different fromthe actual flow rate.
This difference is called a conversion factor, and is normally represented by a ratio
with N2. When gas B is fed into the MFC, which was calibrated with gas A, the
controlled flow rate is shown below.
Theaccuracy of this value maybe decreased ifthe characterof the gas is greatly
different. Also, thevalue of the MFC has been adjusted based onthe viscosity and
density ofthegas,thereforeifa gasother than thecalibrationgasisapplied,the
operating pressure range may be altered. The conversion factor can be set atany desired
value, with an operating rangeof 0.6666 to 1.5000. Iftheconversion factorvalue
exceedsthis range, theoperationoftheMFCbecome unstable.Theaccuracyisdifferent
from the standard specifications of the MFC, whenthe conversion factor is changed.
(4) Digital interface
The MFC features the RS-485 serial digital interfaces. Many special functions
can be employed using the digital interfaces. Please refer to other manuals
(Digital Interface Manual, Special Function Manual, Command Chart).
(5) For general gas control
1) The heat exchange of gas should be made thoroughly to prevent any
difference between the gas temperature and the temperature of the main
body. When there is a big difference between them, errors occur in the
controlled flow rate.
2) Do the temperature control to prevent rapid changes in the temperature of
main body as well as the gas temperature.
3) When adding a heater to the main body, install the heater in a way of not
causing the temperature gradient of the main body.
4) The temperature of the main body should not exceed 120ºC.
(6) For liquid control by vapor pressure
1) Check whether the vapor pressure of the liquid is sufficient (and the
temperature is appropriate).
2) Check whether there is dissolved gas in the liquid (or whether the vacuum
degassing has been made thoroughly).
3) Check whether the surface area of liquid level in the tank is proportionate to
the flow rate in use (If the surface area is small, the control becomes unstable
due to changes in the temperature distribution and vapor pressure. In some
cases, it may become hard to obtain the required flow rate).
4) Do not heat up the liquid locally. Just as the above-mentioned, doing so may
cause a great change in temperature distribution.
5) Control the temperature of tubing and MFC to make a gradual rise in
temperature at the downstream side.
6) If the used materials have reactivity with moisture and oxygen, thoroughly
purge all foreign matter from the tubing and the MFC by baking and
vacuuming before operation.
7) Be sure to do baking and vacuuming after using to keep no residual gas
inside. If it is left with residual gas inside for a long time, it may become very
hard to liquefy again, and the MFC cannot be reused.
8) In the case of internal liquefaction due to the temperature management bias,
after long hours of purging and vacuuming, it can be used again as long as it
has not been corroded by liquefaction.
10. Product warranty
(1) Period
This product is guaranteed for a period of 1 year from date of shipment. Defects
are repaired according to the following regulations.
(2) Scope
Warranty coverage is restricted to this product only. Any other damage caused
by this product is not covered.
(3) Disclaimer facts
The following repairs are not covered by the warranty:
1) Failure caused by by-product of fluid used.
2) Failurecausedbymisuse(includingcarelessoperation)orincorrectrepairormodification.
3) Failure caused by dropping after purchasing.
4) Failure caused by a natural disasters.
Even if thewarranty period is still in effect, the following items may not be repaired.
1) When the kind of fluid used in the product is unclear.
2) The product is returned with fluid remaining inside and safety cannot be
confirmed.
The MFC is a precision instrument. Control may become unstable if electric
noise, temperature change of fluid, pulsation of fluid pressure etc. occurs.
Please be forewarned.
This instruction manual is subject to revision without notice.
http://www.lintec-mfc.co.jp
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