What is On-Delay and Off Delay timer


#1

Timer are used in PLC program to introduce some delays in a logic transition.

On-Delay Timer

For an On-delay timer two different types of contact.

NOTC - Normally opened,timed -closed.

This timer is normally open and that is going to take some time to close.

Contact is open when the relay coil (Timer Input for PLC programming) is de-energized.

When the relay is energized there is a time delay in closing.

NCTO - Normally-Closed,Timed -Open

This timer is normally closed and that’s going some time to open.

Contact is closed when the relay coil is de-energized

When the relay is energized,there is a time delay in opening.

Off delay Timer

NOTO (Normally Open,Timed Open) -

Contact is normally open when the relay coil is de-energized.

When the relay coil is energized,the contact closes instantly.

When the relay coil is de-energized,there is a time delay before the contact open.

NCTC - Normally Closed,Timed Closed Contacts

Contact is normally closed when the relay coil is de-energized.

When the relay coil is energized,contacts opens instantly.

When the relay coil is de-energized,there is a time delay before the contact open.