1. Normally closed input instruction LDI

When the specified bit = 0 (OFF), the normally closed contact is connected, and when the specified bit = 1 (ON), the normally closed contact is disconnected.

In the instruction table, normally closed contacts are represented by LDI (load not), ANDI (AND not), and ORI (or not) instructions, which place the logical NOT (not) of the address bit value at the top of the stack.

Input/Output	Data Type	operand	Description
IN	ON/OFF	X/Y/M/C/T/S, word to Bit(D/V/Z), Local variable(LB)	输入

Instruction table:

NETWORK 000

LDI X000 // Load the logic NOT of input coil X000, X000 must be equal to 0 to activate X000

ORI X002 // /Perform 'OR/NO' operation with input coil X002

ANDI X001 // Perform 'AND/NOT' operation with input coil X001

OUT Y000 // Output coil Y000

图1 LDI