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During initial powering of the FMA 1400/1500 transducer, the flow output signal will be
indicating a higher than usual output. This is indication that the FMA 1400/1500 trans-
ducer 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 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 2-1.
When using the accessory FMA14PD Series Command Module the flow rate will
appear on the display at the front panel. The observed reading is a 0 to 100% indi-
cation (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 of the 15-pin "D" connector (see Figure 2-3) on the top of the
FMA 1400/1500 transducer. The output flow signal is also available at the DATA
connector on the rear panel of the FMA14PD Series Command Module.
The default calibration is performed for 0 to 5 VDC output signal. If 4-20 mA out-
put signal is used for flow indication on the FMA 1400, the accuracy of the actual
flow rate will be in the specified range (+1.0%) of full scale, but the total uncer-
tainty of the output reading may be in the range of +2.0% of full scale. Optional
calibration for 4-20 mA output signal is available upon request at time of order.
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.
5.3
Swamping Condition
If a flow of more than 10% above the maximum flow rate of the Mass Flow Meter
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.
5.4
Set Point Reference Signal (FMA 1400)
FMA 1400 flow controllers have a built-in solenoid valve and allow the user to set
the flow to any desired flow rate within the range of the particular model installed.
This valve is normally closed when no power is applied.
The set point input responds to an analog 0 to 5 VDC reference voltage. This volt-
Содержание FMA 1500
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