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3.4
DISPLAY
The
RheoVac
950 has a 2x20 alphanumeric scroll-through display that shows seven parameters for each
probe. The display shows Air In-leakage, W/A Mass Ratio, Total Mass Flow, Temperature, Pressure,
Relative Saturation, or Actual Volume Flow (as well as Time/Date, Software Version, or Serial
Number). To change the displayed parameter, press the
Scroll
Up or Down arrows. The display units
can be changed from English or Metric units by pressing the
Units
button.
If the Model 950 has two or three probes the display will show two or three serial numbers at a time,
one for each probe. The numbers will be in order, from the lowest serial number to the highest, reading
from left to right on the display. Example: 02611-1, 02611-2 and 02611-3.
3.5
COMMUNICATIONS
Typical
RheoVac
950 instruments have an Ethernet port, two serial communications choices (RS-232
or RS-422) and eight 4-20mA output signals for each probe. Each process variable is a linear, fully
temperature and pressure compensated value on any of these readable outputs. All 4-20 mA output
signals are scaled such that 4 mA represents 0% of the rated full scale value (except temperature, which
is 0°C) and 20 mA represents 100% of the rated full scale value (temperature is 100°C). The standard
full scale values and definitions of all process variables are listed in Table III.
Table III.
Process Variable Definitions and 4-20 mA Range*
PROCESS VARIABLE
4-20 mA
FULL
SCALE
VALUE
PROCESS VARIABLE DEFINITION
A C T U A L V O L U M E FL O W
AC FM [m
3
/hr]
5000
[8,500]
The actual volumetric flow rate of gases leaving the condenser. It is a measure of exhauster
capacity. Decreased capacity means pump degradation.
T O T A L M A S S FL O W
lbs/hr [kg /hr]
10000
[4,536]
Th e to tal m ass flow rate of th e flo wi ng ga s. N ote : this va lue is n ot a me asu re o f air i n-le ak .
It is a measure of total vapor and air removal and exhauster operating capacity.
W A T E R V A PO R M A S S FL O W
lbs/hr [kg /hr]
8000
[3,629]
The water v apor c omp onen t of the flow ing ga s being remo ved fro m the c ond enser.
RheoVac
P R E S SU R E
" Hg [mm Hg]
30
[762]
Absolute pressure at the
RheoVac
probe head. Should be equal to or less than turbine back
pressure.
W A T E R V A P O R S P EC I FI C
VOLU ME [cu. ft/lb]
N/A
Th e inv erse d ens ity of th e w ater v apo r pres ent in the lin e. N ot su pplie d as 4-2 0m A o utpu t.
W AT ER to AIR M AS S R AT IO
20
Ra tio o f w ater va po r flo w r ate t o d ry a ir flo w r ate. D efin es “ va cu um qu ality .”
R E L A TI VE S A TU R A T IO N
[% ]
100
The percent concentration of water vapor in the extraction line relative to saturation.
P A R T I A L P R E SS U R E , W A T E R
"Hg [mm Hg]
N/A
Th e pa rtial pre ssure of w ater v apo r in the vac uum line. N ot su pplie d as 4-2 0m A o utpu t.
A IR IN -L E A K
SCFM [nm
3
/hr]
100
[169.9]
Actual meas ure of air volume flow rate passing the
RheoVac
sensor head, normalized to
standa rd conditions (70°F, 29.9" Hg A).
RheoVac
T E M P E R A T U R E
° F [° C ]
212
[100]
4 mA = 0°C /32°F 20 m A = 1 00°C/21 2°F
Temperature of the flow med ia at the
RheoVac
pro be he ad .
* See Custom Information section (Section 6) for custom units of measure.
Comm unication with the
RheoVac
unit using Intek supplied software is discussed in Appendix A of this
manual.
