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6-12
ML4803A
EMULATION
COMMANDS
This section provides an alphabetical listing of the GPIB commands (mnemonics)
used to program the Model ML2430A Series Power Meter in ML4803A mode.
The emulation mode can be set through the front panel
SYSTEM|more|more|Rear panel|GPIB|MODE menu (see Chapter 4, Operation)
or through the GPIB command EMUL (page 6-86).
All ML4803A GPIB commands that use parameters must not
have a space be
-
tween the command header and the parameter. Multiple parameters must be
separated by semicolons.
Multiple commands may be sent on the same line, but must be separated by
spaces.
The format for ML4803A GPIB commands is:
<command header><parameter 1>;<parameter
n
>;...
The end of the command text must be terminated with a line feed character (0Ah,
decimal 10) or a GPIB End of Transmission State (EOI), or both.
The ML4803A has an array of memory addresses that each hold a structure of
four values; Frequency, Cal factor, Offset, and Reference. The data held for an
entered frequency is not automatically applied, but only applied if that memory
address is called. The frequency value is only a reference to the operator for
which the cal factor and other data is relevant. These memory address sets of
data are only available via the GPIB in ML4803A emulation mode.
SRQ’s The startup and default mode of operation for the ML4803A is to set an SRQ off
then on again for every reading when available. This has the affect of pulsing the
SRQ line very quickly and would make it very difficult to use the ML4803A with
other devices on the GPIB bus that wish to communicate via SRQ’s. These
SRQ’s can be turned off temporarily by the ‘SRQ0’ command. The SRQs will start
again as soon as any data is requested from the ML4803A.
Status Byte The following table and diagram define the Status Byte.
Bit 0 Zero execution Bit set during zeroing. When zeroing is complete the bit is
cleared and the ODR bit and RQS bits are reset.
Bit 1 Cal execution Bit is set during the Cal 0 dBm.
Bit 3 Output data ready ODR bit is cleared and set for every reading when made.
This is done in sync with the RQS bit giving an SRQ.
Bit 5 Command error Set on receiving an unrecognized command. The bit is
cleared by reading the status byte.
Bit 6 RQS bit Indicates that the device is requiring service (SRQ).
6-84 ML2430A OM
ML4803A EMULATION COMMANDS GPIB OPERATION