Upgrading Limit Switches Used As Safety Interlocks

[boomdoom86]

Hello everyone,

My company has an old line for building DC motors. Many machines are from the early 90's and some requests for safety improvements have been made. I'm working with and old coil machine from 1990 in which the guard doors are protected by Honeywell Micro Switch limit switches. There are 4 limit switches wired in series to a single 24VDC input of an Omron Sysmac C60 K. I do not have the software to program this controller, nor is there any room in the enclosure to add safety relays etc.

I'm not required to bring these machines up to code, management just wants to replace any interlocks that can be so easily overcome. I was wondering if there are any devices that could replace these limit switches as is. I.e, requires no power source or very low amperage 24V, no OSSD, uses physical contacts?

We would normally use SensaGuard contactless sensors or Omron D4SL guard locking switches for something like this but with the dated hardware and limited/non-existent cabinet space, I'm looking for a one-for-one replacement. If I can't find something, I'm not sure what to do outside of upgrading to Compact w/ safety relays or GuardLogix.

Thanks in advance!

 

[joseph_e2]

Check out the Omron/Sti MA-10APC4.

I would also push back a little and STRONGLY encourage doing it right, even if you have to add a second enclosure to the system.

 

[jholm90]

Adding/upgrading safety devices to a system is the same as safetying a new system and then the modifier is liable for damages. These days it's not worth the risk for getting in trouble if something happens.

Upgrade to a couple of safety relays with monitored reset and kill all power units that can be cause injury when the door opens. Usually requires power,air,hydraulic circuit modifications and sometimes a new control box to stuff in all the changes. Keep in mind that motion that continues to wind down after the door opens will require locking doors until all motion has stopped before entry.

As always with safety, get a PSHSR review on site from a qualified consultant instead of some internet people ��