ISPSoft User Manual

ISPSoft User Manual
Although the value of the symbol of the VAR_IN_OUT class will be sent to the device that the
caller assigns to the symbol after the function block is executed, the present value in the device
specified by the caller is sent to the symbol before the symbol sends the final operation result to
the device.
*. The data type of the symbol of the VAR_IN_OUT class in a function block in a project for an AH500 series PUC
module can be POINTER. The caller can send the device address to the function block through the symbol
whose data type is POINTER. Please refer to the following section for more information.
Please refer to the function blocks below. FB_Var is the pin of the function block, and P_Var is the
operand that the superior POU (caller) assigns to FB_Var. The data type of P_Var and that of
FB_Var must conform to the basic principle described below. However, in order to make the
writing of a program more convenient, ISPSoft provides some special principles. As long as the
data type of P_Var and that of FB_Var conform to one of the special principles, the system will
regard the data types as legal data types even if the data types does not conform to the basic
principle.
• Basic principle for the general data types
The data type of P_Var must be the same as the data type of FB_Var.
• Special principles for the general data types (Please refer to the following table.)
1. If either the data type of P_Var or the data type of FB_Var is WORD, DWORD, or LWORD, the
data type of the other symbol can be WORD, DWORD, LWORD, INT, DINT, LINT, REAL, or
LREAL. If this condition is met, the data length of P_Var can be larger than or equal to the data
length of FB_VAR.
2. If the data type of P_Var is STEP, the data type of FB_Var can be BOOL. The state of the step
in the caller will be used in the function block.
FB_Var (function block)
Data type
WORD DWORD LWORD INT DINT LINT REAL LREAL BOOL
WORD
DWORD
P_VAR
(caller)
LWORD
INT
DINT
LINT
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