3.2 Remote Operating Modes
This section describes the various methods and modes that are used for remotely controlling the PPM
through the GPIB. Typical sample programs illustrating the use of commands are provided.
3.2.1 PPM IEEE Bus Functions
Remote operation of the PPM is accomplished through the GPIB under the control of a remote
controller/calculator. Bus functions are implemented using the notation of the IEEE-488 1978
specification. These are given in the Bus Functions Summary in Section 3.7.
The following is the general order of events when operating through the GPIB:
1. Parsing of Command String.
2. Actions taken:
a. Autoscale, if requested.
b. Power measurement, and so forth.
c. Output of data upon TACS (Talker Active State)
It is necessary to wait for certain events to complete before sending new commands. Examples of such
commands are AUTO and Marker Placement. If the PPM is placed in TACS and then untalked or if a new
command string is sent, then the taking of data will be terminated as will the autoscale function if it is
not yet complete. Failure of autoscale will result in a service request and the error condition of 60.
Completion will be signaled by the SRQ reporting either success or failure. If the command is AUTO and
Marker Placement, it is necessary to wait for AUTO success or failure, and then Marker Placement
success or failure before expecting any time measurement output data from the PPM.
The controller should time out if the PPM does not complete the appropriate service requests in a
reasonable amount of time; allowing for the autoscale average number, pulse repetition rate, etc.
It is recommended that commands be sent after Device Clear from the controller to guarantee the state of
the instrument. See Section 1.3 for the default settings.
Any pulse profile related command (DUMG, Plot commands, and marker placement commands) will
perform their operation on the collected data when they are received.
Throughout this IEEE Bus operation, delays handled as arguments to commands sent to the PPM are
listed as nnnnnn.nn µs. The PPM will accept resolution down to 0.1 ns or 0.0001 µs. A total of eight
digits are allowed. The position of the decimal point can vary. Arguments should not be sent with excess
digits to the right of the decimal point.
Series 8500A Peak Power Meters
3-2
Manual No. 20790, Rev C, November 1998
To Next Page
Loading...
