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post #1 of (permalink) Old 09-17-2020, 02:55 AM Thread Starter
jeffkrol
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Controllers and Meanwell LDD

While working on another project I decided to answer a few old questions I left hanging

from previous projects.


As some may be aware that I posed in the past on how to modify TC-420 controller to interface with

Meanwell Ldd drivers.
Also those cheap manual dimmers.
I I implied most strip dimmers can be modified in the same way.
I used a $12 Mi-light Bluetooth 4 unit to prove that.

Worked fine.


Except only the tc-420 was actually used. The other "stuff" was just tested.


Well for certain reasons I needed to revisit the Bluetooth unit which btw was a real PIA regarding that and Android OS's of some flavors.
No real need to rehash that though.


Anyways this presented an opportunity to check how the bluetooth unit behaved compared to the TC-420.


Well first both dimmed the Meanwell driver just fine
Both output approx 5V though the TC @ 4.89V was a wee bit better than bt unit.
Now if that was meter error or something else???
Doesn't really matter though since the cycle (on/off) is all that counts in that range.
5V vs 3.3V vs 10V is another animal all together.
Depends on the driver chip and its range or tolerance.


Now the one thing that I always wondered and never had an answer to was the PWM frequency.
The assumption was it would follow the Aduino pattern and usually just be the default setting.
ONE such pattern. Aduino and the like is out of my pay grade
Quote:
prescaler = 1 ---> PWM frequency is 31000 Hz
prescaler = 2 ---> PWM frequency is 4000 Hz
prescaler = 3 ---> PWM frequency is 490 Hz (default value)
prescaler = 4 ---> PWM frequency is 120 Hz
prescaler = 5 ---> PWM frequency is 30 Hz
prescaler = 6 ---> PWM frequency is <20 Hz
And the TC-420 did indeed com out at about 490Hz.
The BT unit at 2.9KHz doesn't really fit the normal patterns so who knows how it's programmed or ...what.


NOTE the Meanwell lists a PWM frequency range of
20(or something) to 1000Hz



So TC was fine.


Now to the point of all this..(FINALLY!!!)

If one would go back though my early stuff on this I always qualified it w? "don't know if they ever change the frequency so YMMV on compatibility.
Well the bluetooth one metered at 2900 Hz but the Meanwell did fine for the short run I subjected it to.
So for anyone thinking about playing w/ these things, keep that in mind.


Oh and decided to "clean up" the wiring on the BT model. Removed 5 zenars and the 5 MOSFETS.
Forgive the crude solder job but I now can just wire in the Meanwells on the old screw terminals.
Of course lost the ability to run both constant current via driver and constant voltage via /MOSFET on the same channel and the correct power supply

which one could do before (also long term untested.)
Anyways just cleaned up a few personal items. Hope someone gets something out of this.




BTW those aren't sold anymore..for the most part. Think Alibaba might have some but not really worth it.
Not sure if any of these have like individual channel/timer/dimmer capability.

"A man with a watch knows what time it is. A man with two watches is never sure"
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