Aalborg DFM Digital User Manual
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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 (!), and the command string is terminated with a carriage return (line feeds
are automatically stripped out by the DFM). See section 2.2.3 for information
regarding communication parameters and cable connections.
8.2 Commands
Structure
The structure of the command string:
!
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.
Several examples of commands follow. All assume that the DFM has been con-
figured for address 15 (0F hex) on the RS485 bus:
1. To get the temperature reading: !0F,TR
The DFM will reply:
!0F72.5 F
(Assuming temperature is 72.5F)
2. To get the pressure reading:
!0F,PR
The DFM will reply:
!0F14.5 PSI
(Assuming pressure is 14.5 PSI)
3. To get a flow reading:
!0F,F
The DFM will reply:
!0F50.0
(Assuming the flow is at 50%F.S.)
4. Set the high alarm limit to 85% F.S.:
!0F,A,H,85.0
The DFM will reply:
!0FAH85.0
** Default address for all units is 11. Do not submit start character and two character
hexadecimal device address for RS-232 option.