Remote Control
Remote Control Commands
6
6-19
Synchronization
*OPC Operating Complete Command
Sending a command using the IEEE-488 bus, followed by the command *OPC in the
same string, sets bit 0 (operation complete) of the 'Standard Event Status Register' to 1
when the function is finished. This bit activates bit 5 of the 'Status Byte Register' (Event
Status Bit), which generates a Service Request. This alerts the controller that the function
is finished. See Page 6-15 to enable the Service Request.
*OPC? Operation Complete Query
Sending the query *OPC? to the generator during a running function causes the
instrument to wait until the function is finished, and then set a 1 in the output queue. The
register can be read out by the controller without a Service Request. When a 1 is
returned, your user program can then continue.
Data in the output queue activate bit 4 of the 'Status Byte Register' (MAV, message
available), which may generate a Service Request. To avoid generating an SRQ, disable
bit 4 (set it to 0). Bit 0 (operation complete) of the 'Standard Event Status Register' is not
affected by *OPC?
Contrary to *OPC, the query *OPC? is more convenient for the RS-232 Interface
because the 1 is directly sent; a separate read-out is not necessary as it would be for the
IEEE-488 Interface.
If *OPC? is sent when the operation is already finished, bit 0 is not set to 1.
*WAI Wait-to-Continue Command
This command sent to the instrument in a message string with other commands causes
the generator to execute the command following *WAI only when the previous
command is completed.
Example:
FREQ 500M;*SAV 10;*WAI;FREQ 400M
The command *WAI in this string causes the instrument to change the frequency setting
to 400 MHz after the previous setting of 500 MHz has been stored.
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