Generic Device Driver
Defining Serial Commands ("Property/Command sequence")

When changing the current value of a property, the device driver not only sends a serial command, but an entire commands sequence. The value assignment is considered complete only if all commands of the sequence were correctly performed. A serial command is repeated until the maximum number of retries is reached.

• Flush receive queue determines whether the driver receive queue is cleared before the first character is sent.

• Error level timeout indicates the priority of the error if no positive reply is received within a specified time.

• If the reply is negative, the error level specified under Error level neg. ack. is returned.

• The error level specified under Error level failed is used if a command sequence cannot be executed.

The list corresponds to the sent command sequence. Each line represents a single command. The commands are sent in the order listed. Each command is composed of the following seven entries:

• Command: Enter the format statement for creating the command string to send. For a description of the format, see below.

• Pos. response: If the instrument sends a positive response in reply to the command string, the response can be entered here. The driver then waits until the response arrives. If the response does not arrive, an error message appears.

• Neg. response: If the instrument sends a negative response in reply to the command string, the response can be entered here. Upon receiving this response, an error message is displayed.

• Exec. time: The command is considered completed when the specified time has passed after the first character was sent.

• Timeout: The positive response must arrive within this period.

• Waittime: If a negative response or no positive response is received, the command is repeated after this period.

• Retries: The command is repeated as specified before being aborted.

For an overview, refer to  The Generic Device Driver.