Fluke NORMA 4000 Operators, User Manual, Page: 24 / 184

Remote Control
Users Guide
1-14
Command Sequence and Command Synchronization
As mentioned above, overlapping execution is possible for all commands. Likewise, the
setting commands of a command line are not necessarily processed in the order they are
received. To ensure that commands are carried out in a specific order, each command
must be sent in a separate command line with a separate viWrite (viPrintf, viQueryf) call.
To prevent overlapping execution of commands, one of the commands *OPC, *OPC? or
*WAI has to be used. Each of the three commands causes a certain action to be triggered
only after the hardware has been set and has settled. The controller can be programmed to
wait for the respective action to occur (see Table 1-1).
Table 1-1. Synchronization by Means of *OPC, *OPC? and *WAI
Command Action after the hardware has settled Programming of controller
*OPC Sets the operation-complete bits in the ESR - Setting of bit 0 in the ESE
- Setting of bit 5 in the SRE
- Waiting for a service request
(SRQ)
*OPC? Writes a "1" into the output buffer Addressing of instrument as a
talker
*WAI Continues the IEC/IEEE-bus handshake.
The handshake is not stopped.
Sending of next command
An example of command synchronization will be found in Chapter 6.
Command synchronization commands will work but are currently not needed (sequential
execution).