Site Considerations; Electronics Console Location; Flowcell Location; Transducer Location - GE DigitalFlow GS868 Startup Manual

Chapter 1. Installation

1.2 Site Considerations

Because the relative physical locations of the flowcell and the Model GS868 electronics console are important, use the
guidelines given in this section to plan the Model GS868 system installation.

1.2.1 Electronics Console Location

The standard Model GS868 electronics enclosure is a Type-4X weather-resistant, dust-tight, indoor/outdoor type.
Typically, the electronics console is mounted in a meter shed. When choosing a mounting site, make sure that the
location permits easy access to the console for programming, testing, and servicing.
Note: For compliance with the European Union's Low Voltage Directive, this unit requires an external power
disconnect device such as a switch or circuit breaker. The disconnect device must be marked as such, clearly
visible, directly accessible, and located within 1.8 m (6 ft) of the Model GS868.

1.2.2 Flowcell Location

The pipeline flowcell consists of the flowmeter transducers and any pressure and/or temperature transducers employed
as part of the flowmeter system. Ideally, choose a section of pipe with unlimited access as the flowcell; for example, a
long stretch of pipe that is above ground. However, if the flowcell is mounted on an underground pipe, dig a pit around
the pipe to facilitate installation of the transducer mechanisms.

1.2.3 Transducer Location

For a given fluid and pipe, the Model GS868's accuracy depends primarily on the location and alignment of the
transducers. In addition to accessibility, when planning for transducer location, adhere to the following guidelines:
1. Locate the transducers so that there are at least 20 pipe diameters of straight, undisturbed flow upstream and 10
pipe diameters of straight, undisturbed flow downstream from the measurement point. To ensure undisturbed flow,
avoid: sources of turbulence in the fluid such as valves, flanges, expansions and elbows; swirl; and dips or low
spots in which condensed liquid may collect.
2. Because condensate or sediment at the bottom of the pipe may cause attenuation of the ultrasonic signal, locate the
transducers on the side of a horizontal pipe, where possible. If limited pipe access necessitates top-mounted
transducers and the sound beam path includes a reflection, shift the transducers to at least 10° off top center. This
will minimize the influence of any sediment on the reflected ultrasonic signals.

1.2.4 Cable Lengths

Locate the flowcell/transducers as close as possible to the electronics console. The factory supplies transducer cables
up to 500 ft (153 m) in length. If longer cables are required, consult the factory for assistance.

1.2.5 Temperature and Pressure Transmitters

When installing temperature and/or pressure transmitters in the flowcell, locate them downstream of the flowmeter
transducers. These transmitters should be positioned no closer to the flowmeter transducers than 2 pipe diameters and
no further away from the flowmeter transducers than 20 pipe diameters.
2 DigitalFlow™ GS868 Startup Guide