Giga-tronics 8003, Руководство по эксплуатации

Страница: 183 / 258

Remote Operation
Manual 20791, Rev. C, June 2001 3-41
Modifiers: Modifiers Used Only With T3 Mode
Modifier Description: ITEMS activates buffered readings in T3 mode. A Buffer
is memory internal to the analyzer set aside to store
readings. The memory is user defined to any length
between 1 and 512 readings. In buffered reading mode,
the analyzer directs readings to the buffer memory until
the buffer is full. When talk-addressed, the analyzer then
sends the entire buffer full of readings to the controller.
Buffering the data allows the analyzer to measure even
faster since it does not have to output the data to the
controller between each reading. Once a buffer is
specified for one channel, all active channels must use a
buffer of the same size. The last ITEMS n command
received determines the buffer size for all channels.
When n=1 or when ITEMS is not specified, the triggered
mode waits to be talk-addressed after each reading. For
buffer sizes greater than 1, the analyzer does not wait to
be talk-addressed after each trigger, but instead adds
the new reading to each active channel’s buffer. When
the buffer is full, the analyzer halts and waits to be talk-
addressed. When talk-addressed, the analyzer sends
the buffered readings to the controller. The entire buffer
for the lowest channel number is sent first, followed by
the buffer for the next highest channel number, and so
on, until all buffers are sent. Each individual data item is
separated from the next by a comma, and data from the
end of one buffer and the beginning of the next is simply
separated by a comma.
Modifier name: ITEMS
Modifier syntax: ITEMS hs numerical value
Valid numerical values: Any integer between 1 and 512
Modifier Description: The RFT (Ready For Trigger) modifier provides a full
hardware handshake for TTL-triggered readings. As
with GPIB-triggered readings, the 8003 will ignore extra
hardware triggers that occur before it is ready to take
another reading. In the TTL-triggered mode, an optional
hardware handshake is provided which is analogous to
the SRQ handshake used in the GPIB-triggered mode.
The hardware handshake mode with data buffers is the
analyzer’s fastest way to collect data. Single channel
reading speeds of greater than 400 readings per second
are possible in this mode. To use the hardware
handshake, add the RFT modifier to the
POWER
command (this assumes you have already selected T3
mode). The AC MOD OUT connector on the 8003
provides the hardware handshake. If the RFT modifier is
given, the 8003 provides a TTL-high at the AC MOD
OUT connector until it receives a hardware trigger on its
INPUT 1 connector. It then sets AC MOD OUT to TTL-
low while it is busy processing the reading. When it has
finished the reading, the 8003 toggles the AC MOD OUT
connector back to TTL-high. Appropriate circuitry in the
test system can decode and use this signal to complete
the handshake. There are a couple of timing consider-