Threaded View
-
17-11-2023 #3
On my own router I have three e-stop buttons around the machine, wired in series. They supply power to a relay with multiple contacts which switch the "enable" signal to the stepper drivers, switch power to the relay which supplies power to the stepper driver supply, and send a signal to the estop input on the motion controller. I should also switch an enable signal to the VFD but I ran out of control wires to the VFD... This is a big advantage of using the estop button(s) to switch a relay - a relay with multiple contacts can then switch multiple different items. Essentially using the estop as a mains switch is a bit brutal - but easy, which is why it's done. However, you are now relying on the reliability of a single component, the relay, to guarantee safe operation. That is why a safety relay is recommended - these are designed to be as reliable as you can practicably achieve and are used for things like safety gate operation. They are not cheap (although I was lucky enough to pick up one as obsolete and damaged packaging which is why I use one). If I were doing it again, I would use a pair of standard relays arranged with coils in parallel and contacts in series or parallel (depending on what they are switching) to give a poor-man's safety relay equivalent. The commercial safety relays include quite a lot of internal complication that is not really required for a machine like this (such as supporting duplicated estop wiring).
Thread Information
Users Browsing this Thread
There are currently 3 users browsing this thread. (0 members and 3 guests)
Similar Threads
-
UCCNC with UB1 Sanity Check
By iforeman in forum CNCdrive (UCCNC)Replies: 6Last Post: 23-06-2020, 06:42 PM -
CSMIO/IP-M - wiring sanity check needed
By Washout in forum CS-Lab (CSMIO)Replies: 6Last Post: 27-10-2019, 07:46 PM -
screening / glitchy operation - sanity check
By dsc in forum General ElectronicsReplies: 21Last Post: 01-12-2013, 11:35 PM -
maximum deflection - sanity check
By dsc in forum Gantry/Router Machines & BuildingReplies: 6Last Post: 11-02-2013, 09:33 AM -
sanity check - constant running, loads and more
By dsc in forum Stepper & Servo MotorsReplies: 4Last Post: 26-11-2012, 12:26 PM
Bookmarks