California Instruments 2001RP, User And Programming Manual

Page: 89 / 130

User and Programming Manual - Rev N
9.5 SCPI Data Formats
All data programmed to or returned from the AC source is in ASCII. The data type may be
numerical or character string.
Numerical Data Formats
Symbol Data Form
Talking Formats
<NR1> Digits with an implied decimal point assumed at the right of the least-significant
digit. Examples: 273
<NR2> Digits with an explicit decimal point. Example:.0273
<NR3> Digits with an explicit decimal point and an exponent. Example: 2.73E+2
<Bool> Boolean Data. Example: 0 | 1
Listening Formats
<Nrf> Extended format that includes <NR1>, <NR2> and <NR3>. Examples: 273.2 ,
2.73E2
<Bool> Boolean Data. Example: 0 | 1
Character Data
Character strings returned by query statements may take either of the following forms,
depending on the length of the returned string:
<CRD> Character Response Data. Permits the return of character strings.
<AARD> Arbitrary ASCII Response Data. Permits the return of undelimited 7-bit ASCII.
This data type has an implied message terminator.
<SRD> String Response Data. Returns string parameters enclosed in double quotes.
9.6 Bus Throughput and Timing Considerations
The 2001RP has a limit on how fast it can process commands sent over the bus. When
developing an application program that controls the 2001RP AC source, this must be
considered. Specifically, if non-query commands (commands that don’t wait for a response such
as output setup commands) are sent at too high a rate, the AC source may not be able to
process them. In that case, a –100 Command Error will be reported.
This condition may exist on both RS232 and GPIB interface modes and is more prone when
faster controllers are used to run the application software. To prevent this condition, it will be
necessary to space out successive commands using a 20 msec delay. Alternatively, commands
could be sent to other instruments in the same system to accomplish the same result.
80 April 2007 2001RP