Messages

1

General Mach Discussion / Re: pwm mode set up issues

« on: October 03, 2008, 11:46:27 PM »

Peter,

Just wanted to let you know I changed the frequency to 500 this morning just as you suggested and guess what.......it works!!!!  Thank you very much for taking the time to help me.
Jeff

2

General Mach Discussion / Re: pwm mode set up issues

« on: October 02, 2008, 04:47:20 PM »

Peter,

I would like to get your opinion on something if I could.  I talked to the board manufacturer and it was suggested to place a resistor across the input terminals of the bc145 and change the jumper from current (where I had it) to volts.  Upon doing this I was able to generate 0-8.8v while reading the output with a voltmeter and changing spindle rpm in the software.  I hooked it up to the dc drive (bc203) and tried it.  The motor will turn, but it is pulsing.....slowly at low rpm and quickly at higher rpms.  I am wondering if the cycle from the pwm port is getting passed through the board since it's switched to volt input and not current.  What do you think?  I may just need to get another board, but naturally having paid over four times what your board costs I am trying to use what I have if possible. 

Thanks for your time,

Jeff

3

General Mach Discussion / Re: pwm mode set up issues

« on: October 02, 2008, 09:45:13 AM »

Hi Peter,

I really appreciate your help here!

I was thinking the pwm signal output from Mach3 was a 4-20ma signal.....I guess that was wrong?   When purchasing the board, I just told them I needed one that received 4-20ma input as I thought that's what I had to work with.....so it's my fault for giving them the wrong info.

I am interested in your board.  Which of the two would you recommend, or will they both provide the same accuracy in my application?  I am using this on a mechanical fuel system flowbench I just built.  I want to create a sweep program that will bring pump speed up to 450rpm for a few seconds (this is where I will begin recording data), then sweep the rpm from 450 to 5000.  I will record the data from this sweep, thus giving me the info I need.   I am using Mach3 to allow me to control the rate of the sweep because at this point I don't know how fast it will need to be to give me the data file size I need.  I just need a board/software combination that will give me a smooth, variable 0-10v signal. 

I have a Baldor BC203 motor drive, and a 5hp Baldor motor p/n CD9105.  I have the drive operational in "manual" mode using a 10-turn pot, but want to be able to automate the sweep to provide repeatable test results.

Thanks for your help!!!!!

Jeff

4

General Mach Discussion / pwm mode set up issues

« on: October 01, 2008, 11:11:25 PM »

Hello, I am new to Mach 3 and have a problem.  I am trying to use the pwm spindle output and something is not working properly.  I need to ultimately get a 0-10v signal to my motor drive, and have purchased a board from Baldor to do just this.  It accepts 4-20ma and outputs 0-10v.....their part number BC145.

I have set up the spindle config, assigned ports, etc. and I think that part is working.  I don't have a way to measure frequency so I'm just using a digital volt meter set on 20ma.  With this connected in parallel with one of the leads at it's attachment point on the converter board, I get a reading of .2 - .8.  Problem is I get no voltage output from the board.   I know it's not advised to check the pwm with a voltmeter, but it's all I've got at the moment and I'm trying to decide if I have some configuration issues in Mach3 or if maybe my board isn't working.....I just got it today from the manufacturer, but it could be defective.  Has anyone ever tried to measure this with a voltmeter and did they get similar values, or does it sound way off? 

My problem may well be in my configuration but I have tried various settings all day and have had no luck.

Thanks in advance for any suggestions, and if more information is needed to make more sense, please ask!

Jeff