Emerson Error Handling, Rosemount 848L, Reference Manual, 00809-0100-4696,Rev AA September

Rosemount 848L

Reference Manual

00809-0100-4696, Rev AA September 2004

Table D-1. Supported Functions

	Required number	Maximum number		Maximum
Function Name	of parameters	of parameters	Function Description	Instances
TON	2	2	TON (a, time);	10
			This function is an on delay. When 'a' is false, this
			function will set its' output to false. When 'a' transitions
			to true, the function's output will remain false for 'time' *
			100 milliseconds before going true.
TP	2	2	TP (a, time);	10
			This function is a pulse timer. When 'a' transitions to
			true, this function will set its' output to true for 'time' *
			100 milliseconds, and then return false.
XOR	2	10	XOR(a, b,...);	NO LIMIT
			This function is false if all parameters are in the same
			state, either all true or all false. Otherwise the function
			is true.

ERROR HANDLING

The syntax of the entered equation is parsed when the target mode transitions from OOS to AUTO. Each equation is checked in order, and when an error is encountered in an equation, the parsing is suspended for the remaining equations, and the target mode is set back to OOS. The equation where the problem was encountered is indicated along with a message as shown in the table below.

Bounds checking on the values of parameters used in the functions are checked during run-time when ACTUAL MODE is AUTO. Errors of this type will be indicated by a bad status in the equations computed value.

Table D-2. Error Handling

Conditions	Status response
No semi-colon appears in the equation.	Missing semi-colon.
More left parenthesis than right parenthesis.	Un-matched (.
More right parenthesis than left parenthesis.	Un-matched ).
A comma placed without a preceding function parameter.	Badly placed comma.
Open and Closed parenthesis without a parameter or	Empty ().
statement contained.
A semicolon is contained prior to finishing an expression.	Badly placed semicolon.
A function call is missing one or more parameters.	Too few parameters in function.
A bad character is present, or a parameter appears outside	Syntax error.
of a function call.
An unknown function is called out.	Unknown function.
An opening parenthesis is located after the closing	Badly placed (.
parenthesis of a function call.
A function call contains too many parameters.	Too many parameters in
	function.
A decimal number was found where an integer was	Invalid number.
expected.
A function result was used as a function parameter where a	Invalid parameters in function.
literal integer number was expected.
A function has been used more than the maximum allowed	Insufficient resources.
instances.
All equations were parsed successfully.	Equation completed.

D-4