This configuration shows an example of how to use the Generic Serial Slave driver to configure the A8NXLT option card for an arbitrary ASCII protocol.

The example protocol is ASCII based and uses 8 data bits per character. The example protocol expects 1 second of gap time between request packets, and therefore there must be less than 1 second of gap time between characters of a single packet.



The example protocol supports the following commands:

Status Request
Reads the inverter's current status including whether its running, actual speed and setpoint speed.


Set Speed Command
Sets the setpoint speed in RPMs.


Run Command
Runs the inverter at the current setpoint speed.


Stop Command
Stops the inverter.



The structure of the request and response packets are as follows, where [CR] incates a carriage return character (0x0D) and [LF] indicates a line feed character (0x0A):


Status Request Command:

Request:
Status[CR][LF]

Response:
[RUN_STATUS][CR][LF]Actual Speed = [SPEED][CR][LF]SetPnt Speed = [SP_SPEED][CR][LF]

[RUN_STATUS] is either Running or Stopped
[SPEED] is the actual speed in RPMs
[SP_SPEED] is the setpoint speed in RPMs


Set Speed Command:

Request:
Speed = [SP_SPEED][CR][LF]

Response:
OK[CR][LF]

[SP_SPEED] is the setpoint speed in RPMs


Run Comand:

Request:
Run[CR][LF]

Response:
OK[CR][LF]


Stop Comand:

Request:
Stop[CR][LF]

Response:
OK[CR][LF]


Invalid Command:

Response:
??[CR][LF]