Acer Wood Runner, Manual

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6.8 FUNCTION OF THE SAFETY SYSTEM
The safety system can be triggered (E-stopped) by any one of four separate devices. These devices are the
Light Curtain, E-stop Button, Home Brake Beam and the Away Brake Beam. The E-stop Button and Light
Curtain are two channel devices meaning that two separate electrical paths are monitored in each.
Breaking the flow of current in either path will cause an E-stop condition to occur. A broken wire or other
failed component in either path will also cause an E-stop. An E-stop condition causes power to be removed
from the air system dump valve and servo amp inputs as well as the Infeed deck motors to stop the
system.
The Brake Beam sensors supply power to Inputs 165 and 166 causing the control system to output power
on Output 202. The current to power the Light Curtain originates from Output 202 and passes through
both channels of this device and the E-stop Button to power the Safety Relay inputs. Breaking either of the
Brake Beams or the Light Curtain beam or pushing the E-stop Button will cause the Safety Relay to open
dumping the system air supply and shutting down the Gantry and Infeed Deck motors. Breaking any of the
Beams will require a special reset procedure which is different from the reset procedure required when
pushing the E-stop button. See section 6 .
The status of the overall Safety System can be viewed on the Main screen on the PC. Here you can view
the actual inputs from each of the safety devices and the reset status of the Safety relay. The cause of the
last E-stop can be viewed here even if it was an intermittent problem. This is explained in the next section.
Shown here is a diagram of the Wood Runner safety system. The main components and the
interconnections between them and the system PC are detailed.
This is not meant to be a wiring diagram;
it is designed to show the theory only . The diagram shows the dual path that must be maintained through
the various safety input devices and the inputs from the devices to the system PC.