Converting a THCAD-300 to a THCAD-10?
Can this be done? Is it just as simple as replacing some resistors on the input side of the card?
I have an oscilloscope and I can recalibrate the card afterwards.
Reading the docs, it seems like the current to voltage chip is the only difference between the -5 and -10. Both resistor networks are 100kOhm.
The input circuitry of the THCAD-5 consists of a current to voltage
converter with a 50 uA full scale range. The input circuitry of the THCAD-10 consists of a
current to voltage converter with a 100 uA full scale range. The THCAD-5 and THCAD-10
have 100K of total input resistance in their input divider section giving them a full scale
input ranges of 100K*50uA = 5V for the THCAD5 and 100K*100uA = 10V for the THCAD10.
are 10K .1% . The 10 through hole resistors on a THCAD-300
are 300K 1% HVR (3500v rated)
The THCAD-5 input current to voltage converter feedback resistor is 49.9k
0.1% The THCAD-10 and THCAD-300 feedback resistor is 24.9K 0.1%
Took a measurement at 7.0V and it was spot on as well.
Not the prettiest soldering job...
Im ready with soldering, is a Fluke 179 Multimeter also okay for calibration?
And for Calibration i connect my multimeter on FO+ and FO- power up the THCAD 300 (now 10) and connect the powersupply with 10v on IN + and -?
sorry for my stupid questions, but this is my first project with linuc cnc and mesa components, also my english is not the best and i dont realy know how to config everything in this HAL thingys, but i read as much as i can in this forum.
Then you can use this calculator to set the scale and offset values for plasmac. jscalc.io/calc/NTr5QDX6WgMThBVb
The Fluke 179 says it can measure up to 100 kHz signals which won't work with the card while in F/1 mode. You'll have to change it to F/32 to get the signal slow enough to what your meter can read.