4

Programming a Normally-Closed Contact in Series

When a Normally-Closed contact is not the first element of the rung, program an

AND NOT with the HHP, as shown below. The example shows how to use the HHP to program a Normally-Closed contact at the first and second positions in a rung.

Ladder Diagram

I3 I4 O18

Timing Diagram

Input I3

Input I4

Output O18

46018

 

Hand-held Programmer

 

START

F3 (NOT)

I3

AND

F3 (NOT)

I4

OUT

 

O18

NAND operation of inputs I3 and I4; output O18 is 1 when I3 and I4 are both 0.

Programming a Normally-Closed Contact in Parallel

To enter a Normally-closed contact in parallel, as shown by I3 in the following example, program an OR NOT with the HHP.

46019

Ladder Diagram

I1O17

I2

I3

Timing Diagram

Input I1

Input I2

Input I3

Hand-held Programmer

START

 

I1

OR

 

I2

OR

F3 (NOT)

I3

OUT

 

O17

OR operation of inputs I1 and I2 and the reverse signal of I3. The output O17 is 1 when either I1 or I2 is 1 or I3 is 0.

Output O17

4-8

Micro PLC Programmer's Guide ± April 1994

GFK-0804B

Page 49
Image 49
GE GFK-0804B manual Programming a Normally-Closed Contact in Series, Programming a Normally-Closed Contact in Parallel