This is the other version I have seen.
I reckon the Motorola stuff should work better. (IMHO)
It has a speed control tacho device, and that circuit can be tweaked to be almost perfect.
On this version the ATMEGA cpu is on the front panel board.
I think the same BOB as previous post is similar.
IMPORTANT thing with these boards is DON'T use the emergency stop except in EMERGENCIES!
I believe the door switch does that too! Stupid plastic thing got lost years ago. Wear glasses.
At every switch on with the ES switch from off damages the relay contacts.
Turning on at mains switch is OK.