Tegam 2411B, Operation Manual

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Chapter 8 Advanced Programming
GPIB (IEEE-488.2) Overview - Error Reporting
Functional Elements (continued)
<PROGRAM MESSAGE>:
WVFM:SINE 1,0;:MODE BURST;:BURST 5;:AMPL 2.5;:EXEC
{ msg 1 } { msg 2 } { msg 3 } { msg 4 }
The semicolon (ASCII 3B) is required to separate <PROGRAM MESSAGE UNITS> within a
<PROGRAM MESSAGE>. For the 2411B a <PROGRAM MESSAGE> can be virtually any length.
The structure for a <RESPONSE MESSAGE> for query responses is similar.
<PROGRAM MESSAGE TERMINATOR> or <PMT> - In order for the device to recognize the end of
a <PROGRAM MESSAGE>, a special terminator is required.
For command messages, the <PMT> can take one of three different formats:
^END - This is defined as sending EOI TRUE and ATN FALSE with the last byte of the
message.
NL - NL represents new line and is an ASCII 0A.
NL^END - A ^END sent along with NL as the last byte.
<RESPONSE MESSAGE TERMINATOR> or <RMT> - For query messages the required terminator is:
NL^END - A ^ND sent along with NL as the last byte.
Error Reporting
There are four basic types of errors that are reported by a device:
Command - In general, when a <PROGRAM MESSAGE> is sent with an error in the syntax, a
command error is reported. The command parser (the module that recognizes individual com
mands) will report the bad command, and look for the next valid command in sequence.
Execution - This error represents either program data which is out of range, or a message which
was not properly executed due to some device condition.In this case the faulty command will
generate the error, but not be performed.
Device Specific - As the name implies, this error is defined by the specific instrument. Currently
there are no Device Specific errors generated by the 2411B.
Query - When a controller or other device attempts to read data from the Output Queue when
no data is present or pending, or when output data is lost, a query error is generated.
To clear an error:
1. Correct the condition which caused the error.
2. Send the *CLS command or read the standard event status register by using the *ESR? query com-
mand.
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