Dwyer DMF User Manual
Page 10
4.1
DMF Mass Flow Controllers
ACCURACY:
+1% of full scale, including linearity for gas temperatures ranging from
59
F
F to 77
F
F (15
F
C to 25
F
C) and pressures of 10 to 60 psia (0.7 to 4.1 bars).
REPEATABILITY:
+0.15% of full scale.
TEMPERATURE COEFFICIENT:
0.1% of full scale/
F
C.
PRESSURE COEFFICIENT:
0.01% of full scale/psi (0.07 bar).
RESPONSE TIME:
DMF 41401-41411: 300ms time constant; approximately 1
second to within +2% of set flow rate for 25% to 100% of full scale flow.
DMF41431-41842: 600ms time constant; approximately 2
seconds to within +2% of set flow rate for 25% to 100% of full scale flow.
GAS PRESSURE:
500 psig (34.5 bars) maximum; optimum pressure is 20 psig (1.4
bars); 25 psig (1.7 bars gauge) for DMF 41842.
DIFFERENTIAL PRESSURES REQUIRED:
5 to 50 psig (0.35 to 3.34 bars) differential
pressures. Optimum differential pressure is 25 psid (1.7 bars). See Table IV for
pressure drops associated with various models and flow rates.
MAXIMUM PRESSURE DIFFERENTIAL:
50 psid for DMF 41401-41433, 40 psid for
DMF 41842.
GAS AND AMBIENT TEMPERATURE:
41
F
F to 122
F
F (5
F
C to 50
F
C).
RELATIVE GAS HUMIDITY:
Up to 70%.
LEAK INTEGRITY:
1 x 10
-9
sccs He maximum to the outside environment.
ATTITUDE SENSITIVITY:
1% shift for a 90 degree rotation from horizontal to verti-
cal; standard calibration is in horizontal position.
OUTPUT SIGNALS:
Linear 0-5 VDC (2000
:
minimum load impedance); 4-20 mA
optional (50-500
:
loop resistance); 20 mV peak to peak max noise.
Contact your distributor or Dwyer for optional RS232 or IEEE488 interfaces.
COMMAND SIGNAL:
0-5 VDC (200K
:
input impedance); 4-20 mA optional.
TRANSDUCER INPUT POWER:
DMF - +15 +5% VDC, 450 mA max, 6.75 watts
max; -15 +5% VDC, 450 mA max; 6.75 watts max; Power inputs are each pro-
tected by a 500mA M (medium time-lag) resettable fuse, and an inverse shunt
rectifier diode for polarity protection.
WETTED MATERIALS:
316 stainless steel, 416 stainless steel, VITON
7
O-rings;
BUNA-N
7
, NEOPRENE
7
or KALREZ
7
O-rings are optional.
7