Positive And Negative Edge Instructions - Siemens S7-1200 System Manual

7.1.3

Positive and negative edge instructions

Table 7- 14 Positive and negative transition detection
LAD FBD
For SCL: You must write code to replicate this function within your application.
1
S7-1200 Programmable controller
System Manual, 03/2014, A5E02486680-AG
SCL Description
Not available Scan operand for positive signal edge.
1
LAD: The state of this contact is TRUE when a positive transition (OFF-
to-ON) is detected on the assigned "IN" bit. The contact logic state is
then combined with the power flow in state to set the power flow out
state. The P contact can be located anywhere in the network except the
end of a branch.
FBD: The output logic state is TRUE when a positive transition (OFF-
to-ON) is detected on the assigned input bit. The P box can only be
located at the beginning of a branch.
Not available Scan operand for negative signal edge.
1
LAD: The state of this contact is TRUE when a negative transition (ON-
to-OFF) is detected on the assigned input bit. The contact logic state is
then combined with the power flow in state to set the power flow out
state. The N contact can be located anywhere in the network except
the end of a branch.
FBD: The output logic state is TRUE when a negative transition (ON-to-
OFF) is detected on the assigned input bit. The N box can only be
located at the beginning of a branch.
Not available Set operand on positve signal edge.
1
LAD: The assigned bit "OUT" is TRUE when a positive transition (OFF-
to-ON) is detected on the power flow entering the coil. The power flow
in state always passes through the coil as the power flow out state. The
P coil can be located anywhere in the network.
FBD: The assigned bit "OUT" is TRUE when a positive transition (OFF-
to-ON) is detected on the logic state at the box input connection or on
the input bit assignment if the box is located at the start of a branch.
The input logic state always passes through the box as the output logic
state. The P= box can be located anywhere in the branch.
Not available Set operand on negative signal edge.
1
LAD: The assigned bit "OUT" is TRUE when a negative transition (ON-
to-OFF) is detected on the power flow entering the coil. The power flow
in state always passes through the coil as the power flow out state. The
N coil can be located anywhere in the network.
FBD: The assigned bit "OUT" is TRUE when a negative transition (ON-
to-OFF) is detected on the logic state at the box input connection or on
the input bit assignment if the box is located at the start of a branch.
The input logic state always passes through the box as the output logic
state. The N= box can be located anywhere in the branch.
Basic instructions
7.1 Bit logic operations
209