Var 2 is the variable holding the second operand. Valid inputs are variables (0x01 through 0x78) and indirect variables (0x81 through 0xF8).
	Var 1 is the variable holding the first operand. Valid inputs are variables (0x01 through 0x78) and indirect variables (0x81 through 0xF8).
	Board ID is a unique number assigned by Measurement & Automation Explorer (MAX) used to send and receive commands and data to or from a specific NI motion controller.
	Ret Vect indicates the destination for the return data generated by this VI. Available return vectors include return data to the host (0xFF), return data to a variable (0x01 through 0x78), return data to an indirect variable (0x81 through 0xF8), and do not return data (0). Refer to Input and Return Vectors for more detailed information.
	error in (no error) describes error conditions that occur before this VI runs. The default input of this cluster is no error. If an error already occurred, this VI returns the value of error in in error out. The VI runs normally only if no incoming error exists. Otherwise, the VI passes the error in value to error out. The error in cluster contains the following parameters: status is TRUE if an error occurred before this VI was called, or FALSE if not. If status is TRUE, code is a nonzero error code. If status is FALSE, code is zero or a warning code. code is a number identifying an error or warning. If status is TRUE, code is a nonzero error code. If status is FALSE, code is zero or a warning code. Use the error handler VIs to look up the meaning of this code and display the corresponding error message. source is a string that indicates the origin of the error, if any. Typically, source is the name of the VI in which the error occurred.
	Bd ID Out is provided for flow control. You can string together NI-Motion VIs by wiring the Bd ID Out terminal of one VI to the Board ID terminal of the next VI.
	error out contains error information. If error in indicates an error, error out contains the same error information. Otherwise, it describes the error status that this VI produces. status is TRUE if an error occurred, or FALSE if not. If status is TRUE, code is a nonzero error code. If status is FALSE, code is zero or a warning code. code is a number identifying an error or warning. If status is TRUE, code is a nonzero error code. If status is FALSE, code is zero or a warning code. Use the error handler VIs to look up the meaning of this code and display the corresponding error message. source is a string that indicates the origin of the error, if any. Typically, source is the name of the VI in which the error occurred.

Using This VI

The Subtract Variables VI subtracts the value of second variable from the value of the first variable and returns the result to the destination specified by the Ret Vect.

V1 – V2 = Result

where:
V1 is the value at Var 1.
V2 is the value at Var 2.
Result is stored in the location pointed to by Ret Vect.

The result can be returned to a new variable or one of the two input variables, returned to the host computer or thrown away. In all cases the condition codes are set according to the resulting value. This value is compared with 0, and the appropriate condition code is set: GREATER THAN, LESS THAN, or EQUAL to zero.

This VI is often used to compare two values prior to executing a conditional jump with the Jump to Label on Condition VI. In this case, the result is typically thrown away by setting Ret Vect = 0.