[SOLVED] Reed Relay symbol meaning?

[mmitchell]

Hi,

I just saw some reed relay symbols in a new project and got confused for the symbols (file link):

1. There are hollow and solid triangle symbols. What do they represent respectively?
2. How to tell whether the relay is on or off when no electromagnet driving current is passing through? Does it relate to the solid/hollow triangles?
3. What does the “E.S.” letters stand for?
4. What is the current (power consumption) needed to run the relay? From the linked datasheet the current needed to close/open the switch is only a few milli-amperes (divide 12V by 1000ohm) of current, is such current enough to activate/deactivate the switch?

Matt

 

[Audioguru]

1) and 2) I have never seen hollow and solid contacts on a relay before. I looked at Reed Relay Symbols is Google Images and hundreds of symbols do not show hollow and solid contacts.
The hollow one is open (I guess it is normally open) so it does not make contact (off) without the coil having power.
The solid one is closed (I guess it is normally closed) so it makes contact (on) when the coil is not powered and powering the coil opens its contacts (off).
The datasheet for the relay should say in words if it is normally open or is normally closed.

3) E.S. could mean anything. Why do they use abbreviations instead of words??

4) The coil's current is probably 12V/100 ohms= 12mA to activate the switching.

Where did the symbols you show come from?

 

[mmitchell]

Hello,

I really think they should give more detailed description in the datasheet.

The symbols (and image) are from here.

 

[FvM]

I don't understand your post, all questions are answered in the datasheet. (There are better readable and more verbose datasheets though).

Generally there's a clear semantic for contact symbols, e.g. how to show normally open and normally closed contact function. This semantic isn't perfectly implemented in the shown symbol, but still well understandable I presume. Nevertheless the datasheet has additional information about contact types in the ordering information. So even if you never saw N.C./N.O. contact symbols or have doubts how to read it, you would still know which relay should be chosen for your application.

Coil parameters are fully specified in the datasheet despite of the short form.

E.S. obviously means electrostatic shield.

 

[Audioguru]

I was right. NO is the hollow Normally Open contact and NC is the solid Normally Closed contact. The datasheet says that E.S. is an optional electrostatic shield.

 

[mmitchell]

I don't understand your post, all questions are answered in the datasheet. (There are better readable and more verbose datasheets though).

Generally there's a clear semantic for contact symbols, e.g. how to show normally open and normally closed contact function. This semantic isn't perfectly implemented in the shown symbol, but still well understandable I presume. Nevertheless the datasheet has additional information about contact types in the ordering information. So even if you never saw N.C./N.O. contact symbols or have doubts how to read it, you would still know which relay should be chosen for your application.

Coil parameters are fully specified in the datasheet despite of the short form.

E.S. obviously means electrostatic shield.

But what about "CO", which is neither "normally closed" nor "normally open"?


Matt

 

[Audioguru]

CO is a Change Over contact at pin 1 that changes over from contacting (NC) with one contact when the coil is not powered to contacting (NO) with another contact when the coil is powered.