Where can I find a list of electrical symbols for different sensors?

[Bourbon daddy]

Hi all, I have been looking the electrical symbols for a proximity sensor and a level sensor. A simple google search has not helped and I have also looked at various manufacturers websites, but still no joy. I was hoping somebody could point me in the right direction to a comprehensive list of sensor symbols. Thanks in advance.

Just to add... The sensors are part of a silo, so I am not looking for a water level sensor.

 

[lewando]

Do you have specific devices in mind? What are the part numbers? Are you looking for a switch or a sensor?

 

[CWatters]

Google images can find some. The one for a proximity switch appears to look like this..

Source mentions ISO 1219-1. See page 4...

http://resources.norgren.com/document_resources/USA/Norgren Graphic Symbol Library.pdf