Mitsubishi Electric MELSEC iQ-F Series Programming Manual page 66

■The input/output point of a function
• It is necessary that all the input points of a function should be connected to other FBD units over connecting wires.
• The data types of the input variables and output variables of a function should be of certain types. It is necessary that the
FBD units to be connected to the input point or output point should be of the same data types.
• Connect a variable element between an output variable (except for ENO) of a CPU module instruction or module dedicated
instruction and an input variable of another function (or function block).
• In a program that connects a function with EN to another function over a connecting wire, the other function must be a
function with EN and the program must connect ENO and EN over a connecting wire, in order to prevent the function from
using an indefinite value.
BOOL_EN_DATA
bLabel1
bLabel2
■When the step relay (S) or SFC block device (BL) is used
If the step relay (S) or SFC block device (BL) is used as a variable element, a conversion error may occur. If an error occurs,
change the variable element to a contact element.
Ex.
The following is the example of rewriting.
Before change
S0
In addition, to use the digit-specified step relay (S) or the step relay with block specification (BL\S), the data size must be
specified correctly. Since the step relay (S) and the step relay with block specification (BL\S) are not targeted for auto data
type conversion, a conversion error may occur if the data size are not the same.
Ex.
The following is the example of rewriting.
Before change
16 bit
K4S0
TRUE
16 bit
BL1\K4S10
7 FBD/LD LANGUAGE
64
7.1 Configuration
AND_E
EN
IN1
IN2
bLabel3
M0
32 bit
D0: UD
32 bit
DMOV
EN ENO
S d D100
(1)
ENO EN
IN1
IN2
(1) Connect ENO and EN over a connecting wire.
After change
S0
After change
16 bit
K4S0
TRUE
32 bit
BL1\K8S10
AND_E
ENO
BOOL_OUT_DATA1
M0
16 bit
D0
32 bit
DMOV
EN ENO
S d D100: UD