Fairbanks X SERIES PR 5410 Process Indicator - Manual (Page 118)

Section 5: SMA Protocol
10/08 118 51207 Revision 1
5 SMA Protocol
5.1 General
The protocol of the 'Scale Manufacturers Association' (SMA) provides a simple access to the scale.
It can be used for reading data, or for executing functions.
The RS-485 interface is used as an interface. Fixed interface settings are 8 bits, no parity and 1
stop bit.
The commands to the instrument are printable ASCII characters starting with = 0A hex and
ending with = 0D hex.
The instrument sends a reply on each received command after approx. 100 µs. With commands that
wait for stability of the weight value, the reply can be delayed by the waiting time.
5.2 Description of Used Symbols
All characters used in this protocol are printable ASCII characters. Characters
and are excepted.
< >
The symbols < and > are used to put communication fields and non-printable ASCII
characters into brackets. These symbols are never part of any communication
message.
A data set starts with a line feed character (line feed = 0A hex).
A data set ends with the carriage return character (carriage return = 0D hex).
‘_’ The underscore or space character is used to mark an ASCII space character (20
hex).
The 'escape' character (1B hex) is used to cancel a command.
‘!’ An ASCII exclamation mark (21 hex) is used for communication errors.
‘:’ An ASCII colon is used as a field delimiter.
‘-’ ASCII minus sign (2D hex)
‘?’ An ASCII question mark (3F hex) is used for unknown or non-supported commands.
‘c’ Command character. All printable ASCII characters are permitted.
Scale status indicator characters; ASCII letters or spaces
For details, see Chapter 5.4.1.
Scale diagnostics indicator characters; upper case ASCII letters or spaces.
For details, see Chapter 5.4.4 .
Weight data including minus sign (right-adjusted) and a decimal point (if any). If
necessary, leading spaces are introduced with a leading zero before the decimal
point. The entire field is always 10 characters long. With some error states, the field
is filled up with minus signs '-'.
Examples: <_ _ _ _ _0.000>; <_ _ _ _11.120>; <_ _ _ _ -1.000>; <- - - - - - - - - ->
Text field of printable ASCII characters; for transporting scale information. The field
has max. 25 characters.
Abbreviation of the used unit. The field is always 3 characters long; it is left-adjusted
and filled up with spaces.