Bridgeport gear selector feedback <explained>

[Joe]

Hello,

As I have mentioned in previous posts we have just started upgrading a Bridgeport V2xt machine to a AllinOne. We are moving along slow do to recent time constraints and I do not want to loose focus on completing the upgrade correctly, which brings up another question on the build (as this is not a running machine yet). The Bridgeport V2xt uses the same gear selector lever (high-neutral-low) as many others so I am sure my question is not limited to specifically to this machine. I have search this forum for this specific question and didn't see that anyone brought this up, for this type of mill.

I see in the manual and on the wiring prints that there is an input available for a choice of four gear positions, if you desire. This V2xt machine uses a proxy switch to indicate only the high position. My thought is to complete the upgrade properly, we will need to add additional switches to this gear selector lever (or change the feedback method all together) to indicate all three positions back to the controller. Assuming that it is in "low" when it is not in indicating (by the only one switch) that is not in the high gear could be bad assumption in the logic, as possibly the lever could also be in the "neutral" position. Where then, the program would start and assumes the spindle is in low gear, but spindle is not actually moving, and then crash. Am I assuming this correctly? So, I definitely need to change the arrangement here to correct the deficiency? Or maybe I am overthinking it... Since it would be at the start of the program the operator would see the issue and quickly stop the program. Not sure why this was not an issue with the old controller setup, but I stopped thinking about that...

Also, it does not appear that a spindle encoder will be added to the machine before it is operational with this new controller, long term yes, but it is a separate project that is going to drag its feet.. So no spindle feedback here in my question.

Any thoughts or comments are appreciated.

Thanks!

Joe

[Centroid_Tech]

The majority of spindles on a Mill only have 2 gears, high and low. All you need is 1 switch which tells the control whether it's in high or low gear. I would say that the majority of systems that I have seen just wire the one switch. The control automatically assumes that the spindle is in high gear unless it's told that it's in another gear. That means that if it's not high gear it's up to the operator to make sure that the lever is actually physically in low gear. I think that if the operator tried to run a program and saw that the spindle wasn't running that they would stop the program and figure out that the gear lever was in the incorrect state. If your switch has it where Neutral is a valid output on the switch, then you could wire that Neutral state to the control and modify the PLC program so that the control will not start a job if the gear lever is in the Neutral position.

You don't need a spindle encoder on a Mill unless you are planning on rigid tapping. In addition to rigid tapping, the spindle encoder does provide you with an accurate display of the spindle speed on the main page but that is not a requirement.

[Joe]

Thanks much for the information.

Joe