Immediate Contact Bit Logic

Inputs/Outputs Operands Data Types
bit (LAD, STL) I BOOL
Input (FBD) I BOOL

Memory Ranges ENO Errors Instruction Support for S7-200 CPUs SIMATIC/International Mnemonics
The immediate instruction obtains the physical input value when the instruction is executed, but the process-image register is not updated.

The Normally Open Immediate contact is closed (on) when the physical input point (bit) is 1.

The Normally Closed Immediate contact is closed (on) when the physical input point (bit) is 0.

In LAD, normally open and normally closed immediate instructions are represented by contacts.

In FBD, normally open immediate instructions are represented by the immediate indicator in front of the operand tic. The immediate indicator may not be present when power flow is used. The instruction can be used to manipulate physical signals in the same manner as ladder contacts.

In FBD, normally closed immediate instructions are also represented by the immediate indicator and negation symbol in front of the operand tic. The immediate indicator cannot be present when power flow is used. The normally closed instruction is constructed by placing the negation symbol on the stem of the input signal.

In STL, the Normally Open Immediate contact is represented by the Load Immediate, AND Immediate, and OR Immediate instructions. These instructions Load, AND, or OR the physical input value to the top of the stack immediately.

In STL, the Normally Closed Immediate contact is represented by the Load NOT Immediate, AND NOT Immediate, and OR NOT Immediate instructions. These instructions immediately Load, AND, or OR the logical NOT of the value of the physical input point to the top of the stack.