82
Designs, materials, weights and performance ratings are approximate and subject to change without notice. Visit
armstrong
international.com for up-to-date information.
Serial Communications – continued
Register Definitions
The meter serial number and those variables that are commonly monitored (mass, volume and energy flow rates, total,
pressure, temperature, density, viscosity, Reynolds number, and diagnostic variables such as frequency, velocity, gain,
amplitude and filter setting) are accessible via the Modbus protocol. Long integer and floating point numbers are accessed
as pairs of 16-bit registers in the register order selected in the Modbus Order menu. Floating point numbers are formatted as
single precision IEEE 754 floating point values.
The flow rate, temperature, pressure, and density variables may be accessed as either the flow meter internal base units or
in the user-programmed display units, which is determined by the programming Output Menu’s “Modbus Units” item. The
display units strings may be examined by accessing their associated registers. Each of these units string registers contain 2
characters of the string, and the strings may be 2 to 12 characters in length with unused characters set to zero. Note that the
byte order affects the order in which the strings are transmitted. If the Modbus Order menu (see page 2) is set to 0-1:2-3
or 2-3:0-1, then the characters are transmitted in the correct order; if set to 1-0:3-2 or 3-2:1-0, then each pair of characters
will be transmitted in reverse order.
