Documentation
Script errors and troubleshooting
TapHome script error messages quoted verbatim — Division by zero, parse errors, run-time errors and context or version errors — with the cause and the fix of each.
A TapHome script fails in one of two ways. A parse error is found while the text of the script is read: the script editor shows it and the script does not run. A run-time error stops a script that is already running. The messages below are quoted verbatim; X, A, B and N stand for the name, type or number in the message.
How errors are reported
A run-time error carries the line of the script and the message:
| |
Where the line break is not shown, the same error reads Line in script: 7 Message: Division by zero. A script stopped by a run-time error gives no value (Null); a Formula smart rule then also has LastState = Null on its next run.
Division by zero
Line in script: 1 Message: Division by zero means that a divisor was exactly 0 when the script ran — typically a device value, such as va2 in va1/va2. Divide only when the divisor is greater than 0:
IF(va2 > 0, va1/va2, 0);
# Result: 0 when va2 is 0, otherwise va1 divided by va2The function form of IF evaluates only the chosen branch, so it never divides by 0. Use va2 <> 0 when the divisor can be negative. More recipes in Examples.
Parse errors
| Message | Cause and fix |
|---|---|
Unknown variable or constant 'X' | A typo, a device value not added to the script, or a word the language does not have: NOT 1 gives 'NOT' — negation is !. Outside a block a missing ; on the previous line can show up as the next name. |
Unknown function 'X' | No such function. MODBUS, TOBYTEARRAY and BYTEARRAY do not exist — use MODBUSR or MODBUSW, TOBYTES and BYTECOLLECTION. |
Wrong number of literals and operators in expression | An operator without an operand, for example 1 == 1. Equality is =, inequality <>. |
Unexpected character 'X' at the end of statement. | The ; before the next statement is missing. Inside a block the message ends with Expected ';', for example Unexpected character 'E' at the end of statement. Expected ';' before END. |
Unexpected character '.' | A property read from a function result, such as AVG(1, 2).Type. Store the value in a variable first. |
Unexpected character ';' in WHILE statement (or DO) | A ; after an inner END or LOOP inside a loop. |
Unexpected keyword 'X' at the end of IF statement. | A ; after an inner END inside an IF block. |
Comment must start on a new line and inline comments are not supported | A # before the ; of a statement, or after an IF or WHILE condition. |
Comparison with NaN is always false. Use the IsNaN method to check for NaN value. | x = NaN — use ISNAN(x). |
Couldn't unescape X | A single backslash in a string; write "C:\\data". |
Too many characters in char literal | Text in single quotes, such as 'ab'; text needs double quotes. |
Variable name must start with letter, Only letters or numbers are allowed in variable name | A name such as 1x or my_value. |
Variable must have initial value provided | VAR x; — give a value, or declare a type: int x;. |
Run-time errors
| Message | Cause and fix |
|---|---|
Division by zero | See Division by zero. |
Specified argument was out of the range of valid values. | PARSETEXT found the left pattern but not the right one. Check with INDEXOF first. |
PARSEJSON - Element not found: 'X' | The JSONPath matched nothing. Pass TRUE as the third argument to get Null instead. |
Operator 'X' not defined for 'A' and 'B' | An operation on incompatible types, for example arithmetic with Null. Check with ISNULL first. |
Cannot cast 'A' to 'B' | A value of a type that cannot be converted, for example text where a number is needed. |
Can not directly set value to device variable | An assignment to a device value outside a Script smart rule. |
More than 1 000 000 loops, stopping loop | A WHILE or DO loop that does not end. |
Cannot use BREAK() outside of WHILE or DO-WHILE | BREAK outside a loop; CONTINUE likewise. |
Interval 'X' is out of range (0-10000) | SLEEP with a negative interval or longer than 10 000 ms. |
Maximum array length is 2048 | BYTECOLLECTION from a hexadecimal text of more than 2048 bytes. |
Invalid array length. Must be greater than 0 and less than or equal 2048 | BYTECOLLECTION with a number of bytes of 0 or more than 2048. |
UINT16COLLECTION: count must be between 1 and 2048 | UINT16COLLECTION, or BOOLCOLLECTION with its own name, with a count outside 1 – 2048. |
GETBIT - bit must be between 0 and 15 | A bit or byte outside the type of the value, here a 16-bit value. |
GETBIT - value X is out of the 32-bit range (-2147483648 .. 4294967295) | A decimal value that is not a 32-bit whole number. |
Return value 'X' does not match required return type constraint: 'T' | A device read script returned a type the device value cannot hold. |
Response is too long (Nbytes). Maximum supported length is 128KB | An HTTP response larger than 128 kB. |
Invalid register number: X | A Modbus register outside 0 to 65535. |
RegisterValueToWrites: Can't write double.NaN to modbus register | NaN written with MODBUSW. |
Context and version errors
| Message | Cause and fix |
|---|---|
X function not supported here. | The function does not work in this kind of script, for example ADDERROR function not supported here. in a smart rule. |
SLEEP function not allowed in this context. | SLEEP in a Script smart rule or a notification script. |
ModbusFunction - unknown modbus device to work with | A Modbus function outside a Modbus script. |
PacketParserFunction - PacketParserContext is null | A Packet parser function outside a Packet parser script. |
DEBOUNCE - invalid argument, must be a device variable | The first argument of DEBOUNCE is an expression, not a device value. |
DEBOUNCE - Function is not available | DEBOUNCE in a script without device values that can be debounced. |
X function not supported. Please update your core unit to be able to use this feature. | The Core is older than the function. |
Data type 'X' not supported. Please update your core unit to be able to use this feature. | A type keyword newer than the Core. |
Modbus data type 'X' not supported. Please update your core unit to be able to use this feature. | Int64, UInt64 or Double on a Core older than 2026.1, build 40595. |
Which build each function needs is in Version requirements.