Common use of Transmitters Clause in Contracts

Transmitters. Transmitters will be used to provide the required 4 to 20 mA dc signals for all controllers and receivers. Transmitters will be of the electronic two-wire type, capable of driving a load up to 750 ohm, and will be powered from the plant distributed control system (DCS). Transmitters will be mounted such that the electronic housing is directly above the valve body. The valve body for all differential pressure transmitters (dP, level, flow) will be installed with sensing points on a horizontal plane. -------------------------------------------------------------------------------- Proprietary Information Page 7 AES IRONWOOD CONTRACT FINAL ISSUE - OCTOBER 30, 1998 -------------------------------------------------------------------------------- 2x1 501G REFERENCE PLANT APPLICATION HANDBOOK -------------------------------------------------------------------------------- CONTROL ENGINEERING DESIGN CRITERIA -------------------------------------------------------------------------------- Static Pressure and Differential Pressure Transmitters Static pressure and differential pressure transmitters shall be Rosemount, model 1151 with smart electronics option, or approved equivalent. Three valve manifolds will be mounted on all differential pressure transmitters for calibration and isolation purposes. Five valve manifolds will be used on instrument applications where it is necessary to fill the sensing line under pressure (e.g., drum level transmitter). All manifolds will have a set of capped 1/4" FNPT test connections on the instrument side of the isolation valve. Level Transmitters Sensing elements for level transmitters will be of the following types: o Static head devices for vessels exposed to atmospheric pressure; air bubbler-type devices may be used if absorption of air by the liquid is not objectionable. (Level transmitters of this type are the same as static pressure transmitters.) o Differential pressure type with constant head chamber for high-pressure and temperature applications. (Level transmitters of this type are the same as differential pressure transmitters.) o Displacement float type for enclosed vessels of limited height. o Moving float type for fuel oil storage tanks. o Ultrasonic type for specialized applications. Flow Transmitters Flow transmitters for general applications will be of the differential pressure type: o Primary Elements. Flow nozzles will be used for main steam flow, feedwater flow, and other critical measurements where weld-in construction is required. Flow nozzles will be made of stainless steel, with dual sets of pressure taps installed in the pipe wall, where required. Installation of flow nozzles and pressure taps will be made in the pipe fabricator's shop, with provisions for witness of the installation process by a representative from the flow nozzle manufacturer. Orifice plates will be used for other flow measurements where flanged construction and higher pressure loss are acceptable. Orifice plates will be made of stainless steel. Orifice flanges will be of the raised-face, weld-neck type with dual sets of taps. -------------------------------------------------------------------------------- Proprietary Information Page 8 AES IRONWOOD CONTRACT FINAL ISSUE - OCTOBER 30, 1998 -------------------------------------------------------------------------------- 2x1 501G REFERENCE PLANT APPLICATION HANDBOOK -------------------------------------------------------------------------------- CONTROL ENGINEERING DESIGN CRITERIA -------------------------------------------------------------------------------- Construction and installation of flow nozzles and orifices will conform to the requirements of ASME Performance Test code PTC-19.5, and discharge coefficients will be predicted in accordance with data published in ASME Research Report on Fluid Meters.