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t100md 888 pwm
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Topic: t100md 888 pwm (Read 14532 times)
kenobe
Jr. Member
Posts: 66
I'm a llama!
t100md 888 pwm
«
on:
May 21, 2008, 06:26:13 AM »
Hi
I try to use the pwm channel 1 (pin 7) to control the speed of my 24 volt dc motor.
I use function setpwm 1,8000,32000.
but when I measure the ouput of pin 7. I dont get the pwm waveform and my dc motor is running at full speed.
What should I do to control the speed of the 24v motor
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Global Moderator
Hero Member
Posts: 3174
Re:t100md 888 pwm
«
Reply #1 on:
May 21, 2008, 09:17:49 AM »
Usually DC motor being an inductive device would not let the PWM current change rapidly enough to sustain a 32KHz PWM. You can try a lower frequency such as 2KHz and you should be able to get a nice wave form.
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Email: support@triplc.com
Tel: 1-877-TRI-PLCS
kenobe
Jr. Member
Posts: 66
I'm a llama!
Re:t100md 888 pwm
«
Reply #2 on:
May 21, 2008, 05:50:31 PM »
Hi
Thanks for your fast reply.
I did tried 2kHz, but result is the same ie: no pwm output wave form and motor running at full speed.
Do I have to do some more things to initialise the pwm beside setpwm 1, 8500,20000?
Thank you very mush
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Global Moderator
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Posts: 3174
Re:t100md 888 pwm
«
Reply #3 on:
May 21, 2008, 08:50:00 PM »
That's the only command you need to use. Are you able to turn the PWM to fully ON by setting duty cycle to 100% (10000) and fully OFF by setting duty cycle to 0% ? If not then your output driver may be bad.
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Tel: 1-877-TRI-PLCS
kenobe
Jr. Member
Posts: 66
I'm a llama!
Re:t100md 888 pwm
«
Reply #4 on:
May 23, 2008, 01:54:00 AM »
Hi
Thanks for your advise
It is conformed that the driver was bad.
How do I replace the driver chip, which IC? where can I get the replacement?
Thanks
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Global Moderator
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Posts: 3174
Re:t100md 888 pwm
«
Reply #5 on:
May 23, 2008, 09:20:53 AM »
Did you check both channels of PWM outputs? Is one channel working and another not working or both not working as you expected. If both are not working as you expected it maybe a wiring issue. The best is not to connect the PWM outputs to any load and then use the SETPWM command to turn the output to fully ON, 50% duty cycle and and fully OFF and observe if the LED is turned ON and OFF accordingly.
The PWM output driver on T100MD888+ is IRL530N. It is a TO220, three pin device (looks like a power transistor) and need to be desoldered. If you are not comfortable handling a soldering iron then it is best to contact your distributor or if you have purchased from us directly then email to support@tri-plc.com and request for an RMA # and send the PLC back to us for repair.
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Email: support@triplc.com
Tel: 1-877-TRI-PLCS
kenobe
Jr. Member
Posts: 66
I'm a llama!
Re:t100md 888 pwm
«
Reply #6 on:
May 23, 2008, 07:35:06 PM »
Hi
Thank you for your reply
I figure out that both pin 7 and 8 have no output.
I will replace the IRL530N.
Thanks again for your support.
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t100md 888 pwm