Aalborg DFM Digital - Manual (Page 6)

2
Attitude limit of Mass Flow Meter is ±15deg from calibration position (standard
calibration is in horizontal position). This means that the gas flow path of the Flow
Meter must be within this limit in order to maintain the original calibration accu-
racy. Should there be need for a different orientation of the meter, re-calibration
may be necessary. It is also preferable to install the DFM transducer in a stable
environment, free of frequent and sudden temperature changes, high moisture,
and drafts.
Prior to connecting gas lines inspect all parts of the piping system including fer-
rules and fittings for dust or other contaminants. Be sure to observe the direction
of gas flow as indicated by the arrow on the front of the meter when connecting
the gas system to be monitored. Insert tubing into the compression fittings until
the ends of the properly sized tubing home flush against the shoulders of the fit-
tings. Compression fittings are to be tightened according to the manufacturer's
instructions to one and one quarter turns. Avoid over tightening which will seri-
ously damage the Restrictor Flow Elements (RFE's)!
Caution: For models DFM 27/37/47 (Multi Parameter versions)
the maximum pressure in the gas line should not exceed 100 PSIA
(6.8 bars). Applying pressure above 100 PSIA (6.8 bars) for
extended periods of time will seriously damage the pressure sensor.
Burst pressure is 200 PSIA (13.6 bar)!
DFM transducers are supplied with standard 1/4 inch (DFM 26/27 and 36/37) or
3/8 inch (DFM 46/47), or optional 1/8 inch inlet and outlet compression fittings
which should not be removed unless the meter is being cleaned or calibrated for
a new flow range.
Using a Helium Leak Detector or other equivalent method perform a thorough
leak test of the entire system. (All DFM's are checked prior to shipment for leak-
age within stated limits. See specifications in this manual.)
2.2 Electrical Connections
DFM is supplied with a 25 pin "D" connector. Pin diagram is presented in figure b-1.
2.2.1 Power Supply Connections
DFM transducers are supplied for three different power supply options:
±15Vdc (bipolar power supply)
DC Power (+) --------------- pin 1 of the 25 pin "D" connector
DC Power Common --------------- pin 18 of the 25 pin "D" connector
DC Power (-)
--------------- pin 14 of the 25 pin "D" connector
ƽ