HP 8153A - Page 103

You cannot control the instrument over the HP-IB if the TtK ONLY indicator is
lit. If this indicator is lit, see “MODE” in Chapter 4 for details on how to change
the HP-IB state.
The Parser
The parser is responsible for reading in messages from the interface, converting
them into commands, and then performing those commands.
Normally, the instrument takes all the Incoming data from the interface port
and puts it in the input queue. When all the data is in the queue, it is parsed.
When the input queue is full, and there are additional bytes at the interface, the
parser
1. removes one byte from the input queue
2. parses it,
3. then takes a byte from the interface port and puts it in input queue.
These three steps are repeated until there are no additional bytes at the
interface.
Parser Type
Beside the HP 8153A commands, the instrument also has a parser that can use
the HP 8152A commands. You can only choose between the parsers from the
front panel in system mode, see “LANGUAGE” in Chapter 4.
Synchronization
Most of the'commands and queries described are executed when parsed. There
are some exceptions for which execution continues afterward. These fall into
three categories.
1. Trigger commands.
2. Measurement commands.
3. The Zero command.
These commands block further execution in the same channel until they have
finished. Commands in the second channel are executed independently. You can
control synchronization for these commands by using the *DPC, >hopC?, and the
>HWAI commands (see Chapter 6 for more details on these commands).
Remote Operation 5-3