Aalborg PWE Digital - Manual (Page 66)

7. RS-485/RS-232 SOFTWARE
INTERFACE COMMANDS
7.1 General
The standard PWE comes with an RS-485 interface. For the optional RS-232 inter-
face, the start character (!) and two hexadecimal characters for the address must
be omitted. The protocol described below allows for communications with the unit
using either a custom software program or a “dumb terminal.” All values are sent
as printable ASCII characters. For RS-485 interface, the start character is always
(!). The command string is terminated with a carriage return (line feeds are auto-
matically stripped out by the PWE). See Section 2.2.5 for information regarding
communication parameters and cable connections.
7.2 Commands Structure
The structure of the command string:
!<Addr>,<Cmd>,Arg1,Arg2,Arg3,Arg4<CR>
Where:
! Start character **
Addr RS485 device address in the ASCII representation of hexadecimal
(00 through FF are valid).**
Cmd The one or two character command from the table below.
Arg1 to Arg4 The command arguments from the table below.
Multiple arguments are comma delimited.
CR Carriage Return character.
** - OMIT FOR RS232 INTERFACE.
Several examples of commands for RS-485 option follow. All assume that the PWE
meter has been configured for address 18 (12 hex) on the RS485 bus:
1. To get a flow reading: !12,F<CR>
The device will reply: !12,50.0<CR> (Assuming the flow is at 50.0% FS)
2. To get current Flow Alarm status: !12,FA,R<CR>
The device will reply: !12,FA,N<CR> > (Assuming no alarm conditions)
3. To get a Main Totalizer reading: !12,MT,R<CR>
The device will reply: !12,MT:93.05<CR>
(Assuming the Main totalizer reading is 93.5)
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