Method 2: Macro Variable Timer
For the second method the robot writes a value in program macro variable #3196 by Ethernet.
This variable can be read at any time but it can only be set by Ethernet, not a g-code program. It has a range of 0-5000 milliseconds. The timer will count down from this value. When it reaches zero, the cell is no longer considered safe. In order to maintain continuity of cell safe, this variable should be reset before its counter reaches zero.
Note: The second method may be better for use with a deadman switch, or in the robot’s teach mode.
For more information on how to write to machine variables refer to Machine Data Collection - NGC.
The machine monitors both signal methods for the presence of a cell safe signal when there is a program running. This feature does not need to be enabled or disabled. If a door is opened when a cell safe signal is present, the active program will continue while the door is open. When there is a valid cell safe signal and the door is open, the spindle speed is limited. The maximum spindle speed is the value of Setting 292, Door Open Spindle Speed Limit. If the door is opened while the spindle speed is above this speed, the spindle will decelerate to the speed limit.
If a door is opened and the cell is NOT safe, the machine will go into a door hold—axis motion stops and the spindle speed is limited.