IET
Decrease font size
Increase font size
Topic Title: - 40°C Safety Switch Cat 4 EN 954-1
Topic Summary: For project in Russia
Created On: 30 March 2011 04:04 PM
Status: Read Only
Linear : Threading : Single : Branch
Search Topic Search Topic
Topic Tools Topic Tools
View similar topics View similar topics
View topic in raw text format. Print this topic.
 30 March 2011 04:04 PM
User is offline View Users Profile Print this message



faisal18may1982

Posts: 235
Joined: 10 May 2003

Hi,

I'm trying to source a Cat 4 (EN 954-1) Safety Switch which will be required to function within its designed parameters between -40°C to +40°C.

The saftey switch can be coded or magnetic and will be fitted to a machine access door.

Any assistance would be greatly appreciated.

Manufacturer, model, part #.

Many thanks

Faisal.
 30 March 2011 09:02 PM
User is offline View Users Profile Print this message


Avatar for dougflorence                                      .
dougflorence

Posts: 74
Joined: 25 July 2008

Hmmm... +40C is no problem, but -40C is pretty damn cold. I have experience of the Middle East where metal touch temperature can get up to about 70C in the sun, but not the other extreme.

Some Schmersal and Bernstein mechanical switches are rated down to -30C. Their magnetic switches are rated down to -25C. I guess if things are icy, switches with no moving parts might be more reliable.

Hinge switches are a good bet. No exposed moving parts to freeze up and they are hard to cheat.

Most cable insulation will be pretty brittle at -40C.

Of course a switch alone will not get you EN954 Cat 4 or EN13849 PLe. You would need two switches to monitor each other, a safety relay to do the monitoring and monitored redundancy throughout the rest of the circuit as well. A question to ask your self is whether you really need EN954 Cat4.

Is there a lateral solution such as a mechanical interlocking system possible? Maybe some sort of token exchange system back to a switch in a warmer location?
 30 March 2011 11:08 PM
User is offline View Users Profile Print this message



ajingram

Posts: 3
Joined: 02 December 2002

Limit switches used on aircraft undercarriages should meet this spec. Cant remember who makes them!
 31 March 2011 04:10 PM
User is offline View Users Profile Print this message



faisal18may1982

Posts: 235
Joined: 10 May 2003

Hi,

Thank you for your replies and input, very much appreciated.

Found a safety door switch manufactured by OMRON, model D4BS

Temp range spec of - 40°C to +80°C

Kind regards

Faisal
Statistics

See Also:



FuseTalk Standard Edition v3.2 - © 1999-2014 FuseTalk Inc. All rights reserved.