On Wednesday I took delivery of a DSP1060 from ChinaCNCzone, and as delivered the door safety is just baffling. The switch itself is a cheap plastic NO pushbutton, rated 1.5 amps at 250 volts, and it’s closed when the door is closed.
They had it wired so that 240V power went straight from the breaker to the door switch, then through the e-stop switch and then on to the filter and the distribution block. The most disturbing consequence of this is that all power to the machine and the rear accessory outlets ran through this one cheap 1.5A switch. That’s just barely within spec under the best of circumstances, not accounting for inrush current.
The most annoying thing is that it’d cause the entire machine to shut off when the door was opened, and then it’d reboot when the door was closed - losing the connection to the PC or network and going through the axis homing sequence again.
Has anyone else seen a machine wired like that? Am I missing something? Was this machine built by morons, or was it a cheap dodge of some safety requirement that they couldn’t otherwise meet with this hardware?
I removed the switch from the power circuit and wired it in to the RDC6445G’s door interlock input, configured it (which required a password that ChinaCNCzone did NOT supply), and verified that it does indeed shut down the laser and axis movement when the door is opened.
That seems like it ought to be fine, though being an embedded systems programmer I know better than to trust embedded software and I’m thinking about adding a second, entirely independent switch in series with the laser enable switch.
What’s typical for safety interlocks on these Chinese machines? Any other gotchas I should be watching for? I’ve already wired in the water chiller’s alarm and made sure that worked. For comparison, my Ostling marking laser has a key lock, shutter switch with indicator light, and a $35 door interlock switch where the DSP1060’s is somewhere under $0.50 retail.