On Tue, 28 Oct 2014, Viesturs L?cis wrote: > Date: Tue, 28 Oct 2014 14:18:30 +0200 > From: "[UTF-8] Viesturs L?cis" <[email protected]> > Reply-To: "Enhanced Machine Controller (EMC)" > <[email protected]> > To: "Enhanced Machine Controller (EMC)" <[email protected]> > Subject: [Emc-users] Question about Mesa THCAD-10 > > Hello! > > There is a plasma machine I built and I used THCAD-10 card for thc > purposes, because the plasma source had such an output signal. > Long story short - the machine has new owner and they want to use > JasicCUT plasma source, which AFAIK does not have 0-10V signal output > for thc, so I will have to connect directly to power leads of plasma > cable. > > How do I calculate, what is the resistance of additional resistors > needed to reduce max voltage from 300V to 10V? The unknown element > here is the current that passes through THCAD card. > > Viesturs
>From the manual: EXTENDING INPUT RANGE The THCAD-10 can have its input range extended by adding series resistance to its inputs. The input circuitry of the THCAD-10 consists of a current to voltage converter with a 100 uA full scale range. The THCAD-10 has 100K of total input resistance in its input divider section giving it a full scale input range of 100K*100uA = 10V. When external series resistors are used to extend the input voltage range, the required resistance value is: (VFS - 10V)/100 uA Where VFS is the new full scale input voltage and REXT is the new external series resistor. For example, to extend the THCAD-10s input range to a 500V a (500-10)/100uA = 4.9M resistor would be required. > > ------------------------------------------------------------------------------ > _______________________________________________ > 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. ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
