The primary function of the Maxiflex M1713B 4PI Module is to monitor dual inputs from up to four oil/gas turbine flow meters and to detect and correct errors in the input pulse streams, and totalise the pulses. The module meets the Level A security requirements of specification ISO 6551:

• Petroleum liquids and gases
• Fidelity and security of dynamic measurement
• Cabled transmission of electric and/or electronic pulsed data.

ISO6551 recommends specific techniques to be employed in the quantitative measurement of petroleum products when royalty, fiscal and custody transfer accounting is required. Five levels of security are specified by this standard, with level A being the most stringent. When  configured for Level A security, the Maxiflex M1713B 4PI module will continuously verify and correct pulse counts received from the flow meters.

This module uses sophisticated correlation techniques in real time to compare the pulse streams and detect missing or added pulses, and accumulates all errors detected and corrected for reporting to the Maxiflex CPU.

This module also provides a pulse output signal selectable from any of the input pulse streams for use with the Maxiflex M1714A Meter Prover module.

A wide range of turbine meter inputs can be accommodated, with any phase. When used with 90 degree phase shifted dual pulse streams, forward and reverse flow is totalised separately.