Ld And Ldn - Omron NY532-5400 Reference Manual

2 Instruction Descriptions

LD and LDN

LD: Reads the value of a BOOL variable.
LDN: Reads the inverse of the value of a BOOL variable.
Instruction Name
LD Load
LDN Load NOT
Variables
None
Function
 LD
The LD instruction reads the value of the specified BOOL variable and outputs it to the next instruction.
If the value of the specified variable is TRUE, then TRUE is output. If the value is FALSE, then FALSE is
output. Use the LD instruction for the first NO bit from the bus bar or for the first NO bit of a logic block.
 LDN
The LD instruction reads the inverse of the value of the specified BOOL variable and outputs it to the
next instruction. If the value of the specified variable is TRUE, then FALSE is output. If the value is
FALSE, then TRUE is output. Use the LDN instruction for the first NC bit from the bus bar or for the first
NC bit of a logic block.
The operation is as shown below if you do not specify upward or downward differentiation.
Instruction
TRUE
LD
FALSE
TRUE
LDN
FALSE
2-16
FB/FUN
---
---
Value of Output
variable value
TRUE
FALSE
FALSE
TRUE
Graphic expression
Variable Variable
Upward Downward
differentiation differentiation
Variable Variable Variable
Upward Downward
differentiation differentiation
NY-series Instructions Reference Manual (W560)
ST expression
None
Variable
None