Rs485 / Rs232 Software Interface Commands; General; Commands Structure - Omega FMA 4000 User Manual

Enable DAC update by typing:
Unit will respond with:
Close BackDoor access by typing:
Unit will respond with:
8.

RS485 / RS232 SOFTWARE INTERFACE COMMANDS

8.1

General

The standard FMA 4000 comes with an RS485 interface. For the optional RS232
interface, 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 RS485 interface, the start character is
always (!). The command string is terminated with a carriage return (line feeds are
automatically stripped out by the FMA 4000). See section 2.2.3 for information
regarding communication parameters and cable connections.
8.2

Commands Structure

The structure of the command string:
!<Addr>,<Cmd>,Arg1,Arg2,Arg3,Arg4<CR>
Where:
!
Addr
Cmd
Arg1 to Arg4 The command arguments from the table below.
CR
Note: ** Default address for all units is 11. Do not submit start
character and two character hexadecimal device address for
RS232 option.
Several examples of commands follow. All assume that the FMA 4000 has been
configured for address 18 (12 hex) on the RS485 bus:
1. To get current calibration tables:
The FMA 4000 will reply:
(Assuming Current Gas table is #0, calibrated for AIR )
2. To get current Alarm status:
The FMA 4000 will reply:
3. To get a flow reading:
4. Set the high alarm limit to 85% of full scale flow rate:
The FMA 4000 will reply:
Start character **
RS485 device address in the ASCII representation of hexadecimal
(00 through FF are valid).**
The one or two character command from the table below.
Multiple arguments are comma delimited.
Carriage Return character.
!11,WRITE,4,N[CR]
!11,DisableUpdate: N
!11,MW,1000,0[CR]
!11,BackDoorEnabled: N
!12,G<CR>
!12,G 0 AIR<CR>
!12,A,R<CR>
!12,N<CR> (Assuming no alarm conditions)
!12,F<CR>The FMA 4000 will reply:
!12,50.0<CR> (Assuming the flow is at 50% FS)
!12,A,H,85.0<CR>
!12,AH85.0<CR>
26