Fluke 5502A - Compound Commands; Coupled Commands; Overlapped Commands

5502A
Operators Manual
5-30
Table 5-5. IEEE-488 Interface Messages (Sent)
Mnemonic Name Function
END End
A message that occurs when the Calibrator asserts the EOI
control line. The Calibrator asserts EOI while it transmits the
ASCII character LF for its termination sequence or
terminator.
DAC Data Accepted Set the handshake signal line NDAC low.
DAV Data Valid Asserts the handshake signal line DAV.
RFD Ready for Data Sets the handshake line NRFD low.
SRQ Service Request
A control line that a device on the bus can assert to show
that attention is necessary. Refer to “Check Calibrator
Status”.
STB Status Byte
The status byte is what the Calibrator sends when it replies
to a serial poll (interface message SPE).
Compound Commands
A compound command is two or more commands in one command line. For example, the
subsequent two commands could be recorded individually,
OUT 1 V, 60 HZ
OPER
where the Calibrator sources 1 V ac at 60 Hz, and then goes into operate, or they could be
mixed into a compound command,
OUT 1 V, 60 HZ; OPER
with a semi-colon as a separator. Be careful when a compound command includes the
coupled commands. (See “Coupled Commands.”)
Coupled Commands
A coupled command refers to two or more commands that are in a compound command
(see “Compound Commands”) that do things that could interfere with each other and
cause a fault. Commands in a compound command are disconnected with the; character.
Compound commands with only coupled commands are not order-dependent.
In Chapter 6, the command shows a checkbox for coupled commands.
The coupled commands, but not the scope commands, are:
CUR_POST DBMZ DC_OFFSET HARMONIC OUT WAVE
An example of the coupled command interference is the command
*RST; OUT 100V, 1kHZ; WAVE SINE
Followed by the commands
WAVE TRI
OUT 10V, 1kHZ
The WAVE TRI causes an error. At 100 V, only sine waves are permitted. The WAVE and
OUT are coupled commands. So, the compound command
WAVE TRI; OUT 10V, 1kHZ
is successful. The WAVE and OUT are programmed together and at 10 V, triangle waves
are permitted.
Overlapped Commands
Commands that start execution but slightly more time to complete is necessary are
overlapped commands, because they can be overlapped by the subsequent command