General - Satec PM172P Reference Manual

1 General

This document specifies a subset of the Modbus serial communications protocol used to
transfer data between a master computer station and the PM172. The document provides
the complete information necessary to develop third-party communications software
capable of communication with the Series PM172 instruments. Additional information
concerning communications operation, configuring the communications parameters, and
communications connections is found in "Series PM172 Powermeters, Installation and
Operation Manual".
IMPORTANT
In 3-wire connection schemes, the unbalanced current and phase readings for power factor,
active power, and reactive power will be zeros, because they have no meaning. Only the
total three-phase power values will be shown.
Most of the advanced features are configured using multiple setup parameters that can be
accessed in a number of contiguous registers. When writing the setup registers, it is
recommended to write all the registers at once using a single request, or to clear (zero) the
setup before writing into separate registers.
Designations used in the guide:
E - available in the meters with the E and EH suffixes
EH - available in the meters with the EH suffix
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