Measurement Computing Digital488/80A - Manual (Page 57)

E? - Query Error Status
SYNTAX E? Returns error status code which indicates the last error encountered. It returns:
• E0 if No Error has occurred.
•
E1 if Unrecognized Command.
•
E2 if Invalid Command Parameter.
•
E3 if Command Conflict Error.
• E5 if Non-Volatile RAM Checksum Failure.
•
E6 if Internal Data Buffer Overrun.
Note: Except for E5 , error is cleared upon reading error status.
DESCRIPTION
The Query Error Status (
E? ) command is used to determine the present error condition on the selected channel of the
Digital488/80A. After execution of the E? command, the present error condition is cleared. The error condition is also
cleared by executing the User Status ( U ) command U0 . When an error has occurred, the front-panel ERROR LED
indicator turns on. The ERROR LED stays on until an E? or U0 command is executed.
If a Non-Volatile RAM Checksum Failure (
E5 ) occurs, then it can only be cleared by doing a save of the configuration
using the Save Configuration ( S ) command. Executing this command updates the checksum to a known value and
clears the E5 error condition.
EXAMPLE 1: No Error.
PRINT#1,"CLEAR08" Line 1: Reset the Digital488/80A.
PRINT#1,"OUTPUT08;E?" Line 2: Query the error status.
PRINT#1,"ENTER08",
INPUT#2,A$,
PRINT A$ Line 5: Display shows: E0 (no errors have occurred).
EXAMPLE 2: Unrecognized Command.
PRINT#1,"OUTPUT08;W5X" Line 1: Send an illegal command to the Digital488/80A (no W command exists).
PRINT#1,"OUTPUT08;E?" Line 2: Query the error status (ERROR LED should be on).
PRINT#1,"ENTER08",
INPUT#2,A$,
PRINT A$ Line 5: Display shows: E1-Unrecognized Command (ERROR LED
should be off)
EXAMPLE 3: Error is cleared.
PRINT#1,"OUTPUT08;E?" Line 1: Query the error status.
PRINT#1,"ENTER08",
INPUT#2,A$
PRINT A$ Line 4: Display shows E0 because the previous error condition was cleared
after reading the error status.
EXAMPLE 4: Invalid Command Parameter.
PRINT#1,"OUTPUT08;P8X" Line 1: Send command with an invalid option (no P8 command option exists).
PRINT#1,"OUTPUT08;E?" Line 2: Query the error status (ERROR LED should be on).
PRINT#1,"ENTER08",
INPUT#2,A$,
PRINT A$ Line 5: Display shows: E2-Invalid Parameter (ERROR LED should be
off).
EXAMPLE 5: Command Conflict Error. (See Next Page.)
Digital488/80A User’s Manual 967695 Digital488/80A Commands 51