The following errors cause bit 4 in the ESR register to be set.
| Error code | Explanation |
| -200 | Execution error
An execution error as defined in IEEE 488.2, has occurred. |
| -203 | Command protected |
| -211 | Trigger ignored
A triggering signal was received and recognized by the device but was ignored because of timing considerations. |
| -212 | Arm ignored
An arming signal was received and recognized by the device but was ignored. |
| -213 | Init ignored
A request for a measurement initiation was ignored as another measurement was already in progress. |
| -221 | Settings conflict
A setting contradicts another setting. The last attempted setting was not executed. |
| -222 | Data out of range
A value of the transmitted command was outside the legal range. |
| -223 | Too much data
More data were sent by the host than the CMU can handle. |
| -224 | Illegal parameter value
An exact value, from a list of possible values, was expected but not received. |
| -225 | Out of memory
The CMU software has insufficient memory to perform the requested operation. |
| -230 | Data corrupt or stale
Possibly invalid data; new reading started but not completed since last access. |
| -240 | Hardware error
A legal program command or a query could not be executed because of a hardware problem in the device. |
| -241 | Hardware missing
A legal program command or a query could not be executed because of a missing device hardware. |
| -250 | Mass storage error
A mass storage error occurred. |
| -251 | Missing mass storage
A legal program command or a query could not be executed because of missing mass storage. |
| -252 | Missing media
A legal program command or a query could not be executed because of missing media; for example, no floppy disk. |
| -253 | Corrupt media
A legal program command or a query could not be executed because of corrupt media; for example, bad floppy disk or wrong format. |
| -254 | Media full
A legal program command or a query could not be executed because of the media was full; for example, no room on the floppy disk. |
| -255 | Directory full
The specified directory is full - no more files can be written. |
| -256 | File name not found
A file with the specified name does not exist. |
| -257 | File name error
The specified file name cannot be used, e.g. because the file does not exist (reading, clearing) or already exists (writing, generation). |
| -258 | Media protected
A legal program command or a query could not be executed because the media was protected. |