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uti15VDC valve configuration, connecting the TEST pin 12 on 15-pin "D"
connectors) to ground will fully open the valve. For FMA 1400's with a +30VDC
valve configuration, connecting the TEST pin to +15VDC will fully open the valve.
6.
MAINTENANCE
6.1
Introduction
It is important that the Mass Flow Meter/Controller is used with clean, filtered
gases only. Liquids may not be metered. Since the RTD sensor consists, in part,
of a small capillary stainless steel tube, it is prone to occlusion due to impedi-
ments or gas crystallization. Other flow passages are also easily obstructed.
Therefore, great care must be exercised to avoid the introduction of any potential
flow impediment. To protect the instrument a 50 micron (FMA 1500/1400 for
ranges up to 10 L/min) or 60 micron (FMA 1500/1400 for ranges above 10 L/min)
filter is built into the inlet of the flow transducer. The filter screen and the flow
paths may require occasional cleaning as described below. There is no other rec-
ommended maintenance required. It is good practice, however, to keep the meter
away from vibration, hot or corrosive environments and excessive RF or magnet-
ic interference.
If periodic calibrations are required they should be performed by qualified per-
sonnel and calibrating instruments, as described in section 7. It is recommended
that units are returned to Omega
7
for repair service and calibration.
CAUTION: TO PROTECT SERVICING PERSONNEL IT IS MANDATORY
THAT ANY INSTRUMENT BEING SERVICED IS COMPLETELY
PURGED AND NEUTRALIZED OF TOXIC, BACTERIOLOGICALLY
INFECTED, CORROSIVE OR RADIOACTIVE CONTENTS.
6.2
Flow Path Cleaning
Before attempting any disassembly of the unit for cleaning, try inspecting the flow
paths by looking into the inlet and outlet ends of the meter for any debris that may
be clogging the flow through the meter. Remove debris as necessary. If the flow
path is not unclogged, then proceed with steps below.
Do not attempt to disassemble the sensor. If blockage of the sensor tube is not
alleviated by flushing through with cleaning fluids, please return meter to Omega
7
for servicing.
6.2.1
Restrictor Flow Element (RFE)
The Restrictor Flow Element (RFE) is a precision flow divider inside the trans-
ducer, which splits the inlet gas flow by a preset amount to the sensor and main
flow paths. The particular RFE used in a given Mass Flow Meter/Controller
depends on the gas and flow range of the instrument.
12
Содержание FMA 1400
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