On Sun, 18 Mar 2012, Kirk Wallace wrote: > Date: Sun, 18 Mar 2012 10:00:19 -0700 > From: Kirk Wallace <[email protected]> > Reply-To: "Enhanced Machine Controller (EMC)" > <[email protected]> > To: LinuxCNC Users List <[email protected]> > Subject: [Emc-users] Current Sensors > > These look pretty handy: > http://www.pololu.com/catalog/product/1187 > > I'm thinking about ways to add load sensing for drives that don't have > this feature yet. Also, I wonder if they are fast enough for PWM signal > control? > > Digikey has some other models of these sensors but it seems for my > purposes, the working voltage isn't high enough, or the current range > is too wide and some resolution is lost. > > Current can also be measured with an opamp measuring voltage across a > current sense resistor, but I'm worried about a common mode voltage in > the hundreds of Volts. Is there away to handle this?
Hall effect sensors are one way. They have the advantage of simplicity and not requiring floating power on top of the swited leg. TI makes some nice isolated current sensors (like the AMC1204) current sense resistors in the low side can also be used but the pair of resistors that are sampled and the exact sample time must be chosen carefully depending on the PWM waveforms (High side series sensors have the advantage the they dont see the switching only the ripple) > -- > Kirk Wallace > http://www.wallacecompany.com/machine_shop/ > http://www.wallacecompany.com/E45/index.html > California, USA > > > > ------------------------------------------------------------------------------ > This SF email is sponsosred by: > Try Windows Azure free for 90 days Click Here > http://p.sf.net/sfu/sfd2d-msazure > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your (")_(") signature to help him gain world domination. ------------------------------------------------------------------------------ This SF email is sponsosred by: Try Windows Azure free for 90 days Click Here http://p.sf.net/sfu/sfd2d-msazure _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
