Det-Tronics PIRVOLHV Volumetric Infrared Hydrocarbon Gas Process Monitor for Heavy Hydrocarbons User Manual
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3 .1
95-8632
CURRENT OUTPUT—
4 to 20 mA current source (non-isolated). For output
levels below 4.0 mA, refer to Table 1.
To convert PIRVOLHV current output to % by volume gas
concentration, use the following formula:
(milliamp signal – 4.0) x 6.25 = % by volume propane
Example:
(4.0 – 4.0) x 6.25 = 0%
(12.0 – 4.0) x 6.25 = 50% by volume
(20.0 – 4.0) x 6.25 = 100% by volume.
Maximum loop resistance: 580 ohms at +24 Vdc. See
Figure 1 for further information.
WIRING—
The PIRVOLHV has five 22 AWG wires, 20 inches (50 cm)
long.
Red = + 24 volts dc
Black = – (common)
White = 4 to 20 mA signal output
Yellow = Calibration input
Green = Chassis ground
Field Wiring: 18 AWG minimum is recommended for field
wiring. Larger diameter wire may be required to maintain
a minimum of 18 Vdc (including ripple) at the sensor for all
operating conditions (see Figure 2). For maximum EMI/
RFI protection, shielded cable is recommended.
TEMPERATURE RANGE—
Operating: –40°F to +167°F (–40°C to +75°C).
Storage:
–40°F to +185°F (–40°C to +85°C).
HUMIDITY (non-condensing)—
0 to 99% relative humidity (Det-Tronics verified)
5 to 95% relative humidity (CSA verified).
ENCLOSURE MATERIALS—
Copper-free aluminum (clear anodized) or 316 stainless
steel.
SAMPLE DRAW CUP—
Material:
Aluminum or stainless steel.
Fittings:
Nickel-plated Brass.
Tubing Size: 1/4 inch O.D.
DIMENSIONS—
See Figure 3 for dimensions of the PIRVOLHV and
Figure 4 for dimensions of the PointWatch Termination
Box Model PIRTB.
SHIPPING WEIGHT (Approximate)—
Aluminum:
1.9 pounds (0.9 kilogram).
Stainless Steel: 5.0 pounds (2.3 kilograms).
Table 1—Current Loop Output Levels
and Corresponding Status Indications
Figure 1—4 to 20 mA Current Loop Resistance
C1964
18
20
22
24
POWER SUPPLY VOLTAGE (VDC)
26
28
30
32
MAXIMUM LOOP RESISTANCE (OHMS)
400
500
600
700
800
900
LOOP RESISTANCE (OHMS)
Figure 2—PIRVOL Wiring Requirements
A2433
18
20
22
24
POWER SUPPLY VOLTAGE (VDC)
26
28
30
32
MAXIMUM DIST
ANCE FROM POWER SUPPL
Y
T
O PIR
VOLHV IN FEET
16 AWG
14 AWG
12 AWG
18 AWG
500
1000
1500
2000
2500
0
Current Level
Status
23.0 mA
Over 90% by volume
20.0 mA
90% by volume
4.0 mA
Zero gas level (0% by volume)
3.9-2.4 mA
Negative zero drift
2.2 mA
Zero calibration in progress
2.0 mA
Span calibration in progress
1.8 mA
Calibration complete - remove gas
1.6 mA
Calibration fault
1.0 mA
Fouled optics
0.8 mA
24 Vdc line low (less than 17.5 Vdc)
0.6 mA
Calibrate input active at power-up
(probable wiring fault)
0.4 mA
Active channel fault
0.2 mA
Reference channel fault
0.0 mA
CPU system fault, warmup