4
4-5GFK-0804B Chapter 4 The Micro PLC Instruction Set
Normally-Open Contact
A Normally-Open contact passes power flow to the right when the associated reference
is equal to 1.
Programming Software Instructions
If you are using the programming software, refer to the instructions on the opposite
page.
Examples and HHP Instructions
The HHP programming keystrokes to create a Normally-Open contact depend on its
position in a rung, as explained below.

Programming Normally-Open Contact at the Star t of a Rung

When a Normally-Open contact is the first element of the rung, program a START, as
shown below.
Ladder Diagram Hand-held Programmer
I1 O17 START
OUT I1
O17
46114
Timing Diagram
The output O17 status follows the
signal of input I1, when I1–1,
output O17=1.
Input I1
Output O17
0
1
0
0
1
0