System information

17-Nov-2014 G2T Programmers Guide Rev-A
57
The Last Command Error (LCE), Last Execution Error (LEE) and Last
Query Error (LQE) registers and their behavior are specific to
UNIVERSAL SWITCHING products. As indicated above, when one of
the errors is encountered, a numeric error code placed in one of
the registers and its flag in ESR is set. The error code can be read
using the GET? Command with the code for that register.
The error code stays in the register until:
• It is replaced by a new error code
• The register is cleared with a *RST, *CLS or processor reset
• The register was read with a *GET? Command when its
corresponding bit in the ESR is cleared.
6.1.6. Procedure for Recovering Errors
The suggested procedure for recovering these errors is to first read
ESR with an *ESR? If its bit in ESR is set, then perform a GET? To
recover the code.
6.1.6.1. Example Register Interaction
The following example should help illustrate the interaction between
these registers and ESR.
• Suppose that the prior command has caused an execution
error 1 (invalid output) and there were no other problems
prior to it.
• Assume that LEE is read by the GET? 16 command. In that
case, the following:
GET? 16; GET? 16; *ESR?; GET? 16; GET? 16; *ESR?
Yield: 1;1;16;1;0;0.
• The first and second reads of the LEE both return 1 since
nothing has happened to change it. Reading the ESR
returns 16 (the set EXE bit) and clears it. The next read of
LEE also returns 1, but since EXE is now cleared, LEE is also
cleared. Finally, the last read of LEE and ESR show the
results of the clearing.