# Timer Symbol



## Big John (May 23, 2010)

The coil is just a regular circle designation with a label, often "TD-whatever".

But a time-delay contact has a specific arrow symbol attached to it. Here's an example of an "on delay" contact in the lower left corner:










An "off delay" would just flip that little arrow symbol so it pointed down.


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## bill39 (Sep 4, 2009)

We only use NFPA symbols, not IEC style so I use the round coil symbol and label it 1TR. But if you're using IEC symbols, then probably just use the retangle.

The real question is how are the timer contacts shown. The old school type or just regular N.O. and N.C. with comments saying instantaneneous, time opening or time closing, etc.


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## MDShunk (Jan 7, 2007)

Sometimes they'll have an extra letter that will say if it's an electronic or pneumatic timer, or sometimes that stuff will just be margin notes.


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## JRaef (Mar 23, 2009)

Here's the official IEC timer symbol:









The solid black box is used if it is an Off Delay (TOFF), the box with an X in it is an On Delay (TON), this one has both because it is a dual purpose timer.


Then here is how you show the contacts:


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