Intek RheoVac 950 - Manual (Page 7)

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Check installation clearance. Each transducer probe is almost 3 feet (0.9m) long and the hot
tap assembly is approximately 13 inches (0.33m) long, therefore, allow minimum clearance
of 4 feet (1.3m) for probe installation. Be sure there are no obstructions around the vacuum
line that will interfere with probe insertion. Figure 3 shows the proper insertion angle. THIS
ORIENTATION IS IMPORTANT FOR PROPER OPERATION.
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Observe the selected sites. They should be convenient for the removal and replacement of
probes at any time for service without building scaffolding or waiting for plant shutdown.
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Check operating conditions. The temperature and pressure limits (see Technical
Specifications; Section 1.3) of the unit should be checked to ensure compatibility with your
application.
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Gases in the air removal line should be free of liquid water, mist or fog. Wetness in the line
will result in erroneous readings from the instrument. If wet conditions exist in the air
removal line, there is either air removal section damage or design flaws which adversely
affect condenser performance. Consult Intek for assistance in evaluating the severity of the
problem and possible remedies.
2.2.2 Electronics Unit Site Selection
The Model 950 typically has two or three electronics enclosures (see Figure 1). The processor
enclosure and other electronics boxes should be installed in a convenient location and should be
kept away from direct sources of heat, such as uninsulated steam lines, or moisture. The
maximum temperature rating of electronics is 120°F; ensure that this temperature will not be
exceeded. Once the wiring connections are made, close and latch down the box lid to protect the
contents from damage and debris. All these enclosures should be located in a dry area and should
be kept clamped shut during normal operation. Do not allow water to get into the enclosures. If
installed outdoors, build a roof over all enclosures to prevent eventual water infiltration.
A. Processor Enclosure: This 12x10 NEMA 4 enclosure houses the display and central
processing unit. Input power (100-250 Vac, 50/60 Hz) is connected inside this enclosure.
This enclosure should be installed in a convenient location and should be kept away from
direct sources of high heat, such as uninsulated steam lines.
B. Distribution Box: This 8x6 NEMA 4 enclosure is typically located near the probe that is
closest to the processor enclosure unit. It is connected to the main processor with an RS-485
bus DeviceNet™ cable, which can be hundreds of feet long. The probe and transmitter RS-
485 cable connections are also made within this box. The probe and transmitter cable
lengths should be 15 ft. or less, if possible.
C. Transmitter Box (optional): This 10x8 NEMA 4 enclosure contains terminals for accessing
the eight 4-20mA signals. It can be located in or near the control room so that the 4-20 wires
do not have to be run from the plant floor. An RS-485 DeviceNet cable runs from the
distribution box to the transmitter box. (There are restrictions on how this can be done, so
check manual Section 6, or contact the factory.)