GE AT868-2-1-1 Flow Meter

To ensure safe and reliable operation of the Model AT868 Flowmeter,the system must be installed and programmed in accordance with theguidelines established by GE Infrastructure Sensing engineers.

Thoseguidelines, explained in detail in this chapter, include the followingtopics:

· Unpacking the Model AT868 system

Selecting suitable sites for the electronics enclosure and theflowcell/transducers

Installing the flowcell/transducersNote: See the enclosed Liquid Transducer Installation Guide(916-055) for detailed instructions on transducer installation.

Installing the electronics enclosure

Wiring the electronics enclosure

Unpacking

Site Considerations

Electronics EnclosureLocation

Carefully remove the electronics enclosure, the transducers, and thecables from the shipping containers.

Before discarding any of thepacking materials, account for all components and documentationlisted on the packing slip.

The discarding of an important item alongwith the packing materials is all too common. If anything is missingor damaged, contact the factory immediately for assistance.

Because the relative location of the flowcell and the electronicsenclosure is important, use the guidelines in this section to plan theAT868 installation

The standard Model AT868 electronics enclosure is a powder-coatedaluminum NEMA 4X, IP66 weatherproof.

Typically, the enclosure ismounted as close as possible to the transducers. When choosing asite, make sure the location permits easy access to the electronicsenclosure for programming, maintenance and service.

Note: For compliance with the European Union's Low VoltageDirective (73/23/EEC), this unit requires an external powerdisconnect device such as a switch or circuit breaker.

Thedisconnect device must be marked as such, clearly visible,directly accessible, and located within 1.8 m (6 ft) of theModel AT868.

Flowcell Location

Transducer Location

Ideally, choose a section of pipe with unlimited access; for example, along stretch of pipe that is above ground.

However, if the flowcell isto be mounted in an underground pipe, dig a pit around the pipe tofacilitate installation of the transducers

For a given fluid and pipe, the Model AT868's accuracy dependsprimarily on the location and alignment of the transducers. In additionto accessibility, when planning for transducer location, adhere to thefollowing guidelines:

Locate the transducers so that there are at least 10 pipe diametersof straight, undisturbed flow upstream and 5 pipe diameters ofstraight, undisturbed flow downstream from the measurementpoint.

Undisturbed flow means avoiding sources of turbulence inthe fluid such as valves, flanges, expansions, and elbows; avoidingswirl; and avoiding cavitation.

Cable Lengths

Transducer Cables

Locate the electronics enclosure as close as possible to theflowcell/transducers, preferably directly on the flowcell.

However,GE Infrastructure Sensing can supply transducer cables up to 1.000 ft(300 m) in length for remote location of the electronics enclosure. Iflonger cables are required, consult the factory for assistance.

When installing the transducer cables, always observe establishedstandard practices for the installation of electrical cables.

Do not routetransducer cables alongside high amperage AC power lines or anyother cables that could cause electrical interference. Also, protect thetransducer cables and connections from the weather and corrosiveatmospheres.

Note: If you are using your own cables to connect the transducers tothe electronics console, they must have electricalcharacteristics identical to the cables supplied by the factory.

For transducer frequencies up to 2 MHz, the cables in eachpair must be the same length within +4 in. (10 cm). Fortransducer frequencies above 2 MHz, the cables in each pairmust be the same length within +0.5 in. (1.25 cm).

Installing a Flowcell

Mounting the AT868Electronics Enclosure

A flowcell is the section of pipe where the transducers are mounted. Itcan be created either by mounting the transducers on the existingpipeline or by mounting them on a spoolpiece.

A spoolpiece is aseparately manufactured pipe section, matched to the existing pipe,which contains ports for mounting the transducers. This approachallows the transducers to be aligned and calibrated before insertingthe spoolpiece into the pipeline.

For detailed instructions on installingthe transducers and/or spoolpiece, refer to the supplied drawings andthe enclosed GE Infrastructure Sensing Liquid TransducerInstallation Guide (916-055).

The standard Model AT868 electronics package is housed in anpower-coated aluminum NEMA 4X, IP66 weatherproof enclosuresuitable for indoor or outdoor use.

Refer to Figure 1-3 on page 1-13for the mounting dimensions and the weight of this enclosure.