New contact block design for Emergency Stop devices from Siemens

This entry is part 9 of 13 in the series Emergency Stop

One issue that fre­quently comes up when inspect­ing machinery is the con­tact blocks used on emer­gency stop devices. Until now, e-​stop devices were nor­mally fit­ted with the same con­tact blocks used on oth­er oper­at­or devices, and in cases where the e-​stop sys­tem is single chan­nel, you could lose the con­tact block off the back of the oper­at­or device and not be able to detect it. Since the latch­ing detent device on the but­ton is part of the but­ton and not part of the con­tact block, the but­ton would appear to latch down nor­mally, but the machine would keep running!

I got a news­let­ter in my email today from Siemens that included the fol­low­ing snip on their new 3SB34 emer­gency stop con­tact block and I though I’d share it with you!

Emergency stop con­tact block with mount­ing monitoring

Siemens E-Stop Contact Block 3SB34
Siemens 3SB34 E-​Stop Contact Block

It is com­mon prac­tice to equip actu­at­ors such as EMERGENCY STOP with stand­ard con­tact blocks. Now the new 3SB34 con­tact block with mount­ing mon­it­or­ing from the SIRIUS fam­ily offers increased safety – auto­mat­ic­ally mon­it­or­ing not just the con­nec­tion to the actu­at­or but also the cor­rect mount­ing on the EMERGENCY STOP. The mon­itored con­tact blocks are nor­mally closed con­tact blocks with pos­it­ive open­ing oper­a­tion. If the mount­ing is defect­ive or should it fall off the actu­at­or, the innov­at­ive con­tact block trig­gers an auto­mat­ic shut­down of the machine or plant (safe state). As long as the plant is oper­at­ing, you can be sure that all the neces­sary con­tacts are func­tion­ing perfectly.

The advant­ages are obvi­ous:
– Increased safety thanks to the test required for ini­tial com­mis­sion­ing
– Higher plant avail­ab­il­ity thanks to auto­mat­ic mon­it­or­ing of the mount­ing
status dur­ing oper­a­tion (accord­ing to the Machinery Directive)
– Space-​saving thanks to a com­pact design and small install­a­tion depth (max. 63 mm)
– Free slots for fur­ther con­tact blocks due to integ­rated mount­ing monitoring

The con­tact block is avail­able in two ver­sions – with screw con­nec­tion 3SB3400-​0M or with spring-​loaded con­nec­tion 3SB3403-0M.

For fur­ther inform­a­tion, click here.

Since I don’t sell any kind of con­trol products, you’ll have to talk to your loc­al Siemens rep­res­ent­at­ive to get pri­cing and availability.

If any­one has any exper­i­ences with these products that they would like to share, please leave a comment!