[Emc-users] spindle tachometer strangeness
First, the Hurco is alive! I carved emc/axis into a piece of aluminum yesterday; thanks to all the participants for creating supporting emc/lcnc/linuxcnc/etc. Now to the next level - I'm using a hall sensor to detect spindle rpm; I get a clean low-going pulse each revolution, as expected. This is fed as input to the A channel of a hostmot2 encoder (running in counter mode). The velocity output always reports as a negative number - consistent at a given speed, larger abs. value at higher rpms, so it seems to be properly following whatever algorithm it uses. I've tried forcing the B channel to both high and low states without change in output behavior. Any thoughts about what may be going on? thanks lloyd -- Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] spindle tachometer strangeness
On 26 May 2012 16:21, lloyd wilson llwilso...@rochester.rr.com wrote: The velocity output always reports as a negative number I don't know why it does that, but setting the encoder scale to a negative number will fix it. -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto -- Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] spindle tachometer strangeness
could you negate the scale of the encoder counter? sam On 05/26/2012 10:21 AM, lloyd wilson wrote: First, the Hurco is alive! I carved emc/axis into a piece of aluminum yesterday; thanks to all the participants for creating supporting emc/lcnc/linuxcnc/etc. Now to the next level - I'm using a hall sensor to detect spindle rpm; I get a clean low-going pulse each revolution, as expected. This is fed as input to the A channel of a hostmot2 encoder (running in counter mode). The velocity output always reports as a negative number - consistent at a given speed, larger abs. value at higher rpms, so it seems to be properly following whatever algorithm it uses. I've tried forcing the B channel to both high and low states without change in output behavior. Any thoughts about what may be going on? thanks lloyd -- Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] spindle tachometer strangeness
negativity should work, understanding would be more satisfying. -ldw On 05/26/2012 12:12 PM, sam sokolik wrote: could you negate the scale of the encoder counter? sam On 05/26/2012 10:21 AM, lloyd wilson wrote: First, the Hurco is alive! I carved emc/axis into a piece of aluminum yesterday; thanks to all the participants for creating supporting emc/lcnc/linuxcnc/etc. Now to the next level - I'm using a hall sensor to detect spindle rpm; I get a clean low-going pulse each revolution, as expected. This is fed as input to the A channel of a hostmot2 encoder (running in counter mode). The velocity output always reports as a negative number - consistent at a given speed, larger abs. value at higher rpms, so it seems to be properly following whatever algorithm it uses. I've tried forcing the B channel to both high and low states without change in output behavior. Any thoughts about what may be going on? thanks lloyd -- Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] spindle tachometer strangeness
2012/5/26 lloyd wilson llwilso...@rochester.rr.com: Now to the next level - I'm using a hall sensor to detect spindle rpm; I get a clean low-going pulse each revolution, as expected. This is fed as input to the A channel of a hostmot2 encoder (running in counter mode). My apologies, if I am missing something, but the described behavior - one pulse per revolution - seems more like index signal. The velocity output always reports as a negative number - consistent at a given speed, larger abs. value at higher rpms, so it seems to be properly following whatever algorithm it uses. How much does reported velocity differ from actual velocity? If index is linked to quadrature signal, then it should report _a lot_ slower than actual velocity, although it will scale up correctly any increase/decrease in velocity. -- Viesturs If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto -- Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] spindle tachometer strangeness
On Sat, 26 May 2012, lloyd wilson wrote: Date: Sat, 26 May 2012 12:20:38 -0400 From: lloyd wilson llwilso...@rochester.rr.com Reply-To: Enhanced Machine Controller (EMC) emc-users@lists.sourceforge.net To: Enhanced Machine Controller (EMC) emc-users@lists.sourceforge.net Subject: Re: [Emc-users] spindle tachometer strangeness negativity should work, understanding would be more satisfying. -ldw The counter mode counts up or down depending on the state of the B encoder input at the FPGA (count up for high, down for low). You can verify the B encoder input state by reading the GPIO bit that maps to the B encoder input of interest. complicating factors: 1. The up/down mode is determined by the state at the FPGA pin. Most input conditioning daughterboards invert the encoder signals so the external state will be opposite of the FPGA pin state. 2. Some configurations do not have B inputs as they are just used for counting applications. In this case the counter will always count down (since unconnected inputs are terminated in a 0 state internally in the FPGA) Peter Wallace -- Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] spindle tachometer strangeness
On 05/26/2012 12:52 PM, Peter C. Wallace wrote: snip 2. Some configurations do not have B inputs as they are just used for counting applications. In this case the counter will always count down (since unconnected inputs are terminated in a 0 state internally in the FPGA) Peter Wallace This is my understanding; I tried changing the state of B input without a change in the count direction; maybe I hit the wrong pin. As long as count mode provides valid rate information, I'll plan on using scaling - or is there an absolute value hal comp? -- Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
