The following errors cause bit 5 in the ESR register to be set.
| Error code | Explanation |
| -100 | Command error
Generic error message that cannot detect a more specific error. |
| -101 | Invalid character
The command contains a character which is invalid for that type. |
| -102 | Syntax error
The data type received is not accepted at this position. |
| -103 | Invalid separator
The semicolon was omitted after a program message unit. |
| -104 | Data type error
The recognized data element is of the wrong type (e.g. character data instead of numeric data) |
| -105 | GET not allowed
A GET was received within a program message. |
| -108 | Parameter not allowed
The command contains parameters at a position where they are not accepted. |
| -109 | Missing parameter
The command does not contain the required parameters. |
| -111 | Header separator error
A character which is not a legal header separator was encountered while parsing the header; for example, no white space followed the header. |
| -112 | Program mnemonic too long
The header contains more than 12 characters. |
| -113 | Undefined header
The sent command header has not been defined. |
| -114 | Header suffix out of range
The command contains an illegal numeric suffix. |
| -120 | Numeric data error
An invalid character for the data type being parsed was encountered. |
| -121 | Invalid character in number
The command contains an illegal numeric suffix. |
| -123 | Exponent too large
The magnitude of the exponent is too large. |
| -124 | Too many digits
The decimal numeric data element contains too many digits. |
| -128 | Numeric data not allowed
The command contains a numeric data element the device does not accept in this position. |
| -131 | Invalid suffix
The suffix is not appropriate for this command. |
| -134 | Suffix too long
The suffix contains more than 12 characters. |
| -138 | Suffix not allowed
A suffix is not allowed for this command or at this point of the command. |
| -141 | Invalid character data
The character data element contains an invalid character or the element is not valid for this command. |
| -144 | Character data too long
The character data element contains more than 12 characters. |
| -148 | Character data not allowed
The character data is prohibited for this command or at this point of the command. |
| -151 | Invalid string data
A string data element was expected, but was invalid for some reason. |
| -158 | String data not allowed
The command contains a legal string data element which is not allowed at this point. |
| -161 | Invalid block data
The command contains illegal block data, e.g. no numeric data element is sent after the introductory #. |
| -168 | Block data not allowed
The command contains legal block data which are not allowed at this point. |
| -171 | Invalid expression
The expression data element was invalid; for example, unmatched parentheses or an illegal character. |
| -178 | Expression data not allowed
A legal expression data was encountered but was not allowed by the device at this point in parsing. |
| -180 | Macro error
An error occurred when defining a macro or executing a macro. |