X HOMING PROBLEM ON VERTICAL ROUTER

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Jeffo
Posts: 2
Joined: Sat 06 Oct , 2018 12:10 pm
Hardware/Software: Denford vertical router running vr5 milling and Denford Nova mill running mach3 both on windows xp

X HOMING PROBLEM ON VERTICAL ROUTER

Post by Jeffo » Sun 07 Oct , 2018 11:44 am

Hi
I am new to this forum, and wondering if anyone can help with advise on a problem I am having on my Denford vertical router. The unit has worked fantastically for the years that I have owned it.
My issue with the unit is the x axis will no longer home. The problem started months ago, when it would require me to restart VR milling several times to get the x axis to home, the problem has got worse over time, until finally it has stopped homing completely. Before the unit stopped working, once homed it would run perfectly until switched off, problem would occur when switched on again. The system runs using a Baldor Nextmove esb2 motion controller and Baldor microflex servo control connected to baldor BSM63N-275AF Servo motor. The microflex servo control for the x axis shows a red flashing indicator when the y and z units indicators turn green. After reading the tech spec on the microflex unit, it states that 5 flashes of the indicator followed by a pause indicates a feedback error. I tried swapping the the x axis motor to the y axis connections and the problem then showed on y axis. The fact that the problem moved to the y axis lead me to think the problem was with motor unit or internal encoder.
I dismantled the end unit from the motor and found a hengstler f142500/4nf5j15 encoder inside. After finding the spec for the motor, I powered the encoder up using my bench power supply pin 1 on the plug dc+5v pin 2 ground. Using an oscilloscope I checked the outputs from the encoder, the channels pin 3 is the A channel, pin 4 is the A- channel ,pin 5 is B channel, pin 6 is B- channel, pin 7 is the Z channel and pin 8 is the Z- channel. Both A and B channels gave perfect square wave outputs, the Z channel gave a sync pulse every revolution of the encoder. On checking the U V W channels on the encoder, that I take to be feedback channels I see nothing on my scope, and am wondering if they require a load to be applied. Any advise or help would be much appreciated.

Martin
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Re: X HOMING PROBLEM ON VERTICAL ROUTER

Post by Martin » Sun 07 Oct , 2018 19:08 pm

I have seen similar issues before & it was nearly always resolved by unplugging both the both encoder & control feed plugs from the microflex drive.

DavidB
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Re: X HOMING PROBLEM ON VERTICAL ROUTER

Post by DavidB » Sun 07 Oct , 2018 20:30 pm

That sounds like the old classic problem with solder coated contacts where oxidisation would creep along the contacts and eventually result in signal issues especially in low current circuits. Standard practice is just to unplug and plug the chips/connectors in again and that action wipes the contacts of the oxide film normally correcting the problem. I saved a glass blower many hundreds of £s with this simple fix as the temperature controller she uses was designed to have the guts pulled from the panel mounting box to allow hot plugging and replacing a controller without accessing all the back wiring, she now has made it part of her annual service process to remove the guts and refit. Electronics don't last forever though and she has had to replace a controller recently but my advice extended the controller life by about 8 years whereas others were happy to sell her a new controller at around £300.

Jeffo
Posts: 2
Joined: Sat 06 Oct , 2018 12:10 pm
Hardware/Software: Denford vertical router running vr5 milling and Denford Nova mill running mach3 both on windows xp

Re: X HOMING PROBLEM ON VERTICAL ROUTER

Post by Jeffo » Tue 30 Oct , 2018 10:47 am

Hi All,
thank you for your suggestions regarding my homing problem, finally figured the problem out. The cause of my problem was a faulty encoder on the x axis baldor bsm63n 275af servo motor, the hall effect switches on the output failed. Setting the new encoder up was a bit of a pain getting the lock up angle correct. I received great help from British encoders sourcing a new encoder in particular David.
regards
Jeff

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