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Issues with TC420 controller stability?

chelonius_frank

Seedling
Joined
5 Aug 2022
Messages
1
Location
Zwolle, Netherlands
Hi people!
My name is Andres and I write to you from the Netherlands. I used a TC420 coupled to an HLG-320H-24 Mean Well driver (constant V and I) to drive RGB-CCT single chip leds. I was able to program cool photoperiod schedules but after some time, I found out that the light intensity of the LEDs started changing after some time. Let's say I set it at 10 μmoles/m2/s , then after a couple of weeks it was double that amount! Now, I do not understand if this is an issue of the TC420 itself or not (maybe power line noise affecting the led driver or sthg else???). Has anyone experienced similar issues? If so, do you know if there is a better (more stable) controller?

Thanks!
Andres
 

zozo

Member
Joined
16 Apr 2015
Messages
8,332
Location
Netherlands
I'm not quite sure what you did, did you put a TC420 channel to the driver PWM port? Then I guess it's a TC420 issue because it indeed dims with a PWM signal but the output isn't PWM. It is designed to dim DC24/12Volt constant voltage LED setups that require a constant voltage PSU to control SMD strips. And the Meanwell driver wants a proper PWM signal... To get to the proper PWM signal to control the constant current driver you should open up the TC420 and solder a wire to the MOSFET output Gate of 1 channel per driver.

Schermafbeelding 2022-08-05 155100.jpg


Schermafbeelding 2022-08-05 155125.jpg


There are/were tutorials with diagrams to find to control constant current drivers with the TC420. It used to be on the website tc420.net but this one is no longer available. The TC420 is becoming a tad old fashion and obsolete, not many people still use it.

The workaround is discussed in this topic.

Or here

I might be in doubt because the strips you link to seem to be DC24 V constant voltage SMD... Then you don't need a constant current driver but a constant voltage PSU with sufficient Wattage output.
 
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swyftfeet

Member
Joined
29 Oct 2021
Messages
153
Location
WNY
I'm not quite sure what you did, did you put a TC420 channel to the driver PWM port? Then I guess it's a TC420 issue because it indeed dims with a PWM signal but the output isn't PWM. It is designed to dim DC24/12Volt constant voltage LED setups that require a constant voltage PSU to control SMD strips. And the Meanwell driver wants a proper PWM signal... To get to the proper PWM signal to control the constant current driver you should open up the TC420 and solder a wire to the MOSFET output Gate of 1 channel per driver.

View attachment 192003

View attachment 192004

There are/were tutorials with diagrams to find to control constant current drivers with the TC420. It used to be on the website tc420.net but this one is no longer available. The TC420 is becoming a tad old fashion and obsolete, not many people still use it.

The workaround is discussed in this topic.

Or here

I might be in doubt because the strips you link to seem to be DC24 V constant voltage SMD... Then you don't need a constant current driver but a constant voltage PSU with sufficient Wattage output.

it says you can vary the resistance 0-10V, or use a 10V PWM or open for full output on the driver. You're not trying to modulate the input line on that driver are you?

if you are and the PWM is something other than 10V, as specified on the driver, your going to get something but who knows what? I didnt dig into the schematic/threads far enough to figure what the Voltage on the gate of MOSFETs are.

If I'm getting what your trying to do the PWM line(s) white and blue should remain unconnected and you should just be using the V+ and GND to the tc420. let the TC420 handle the dimming. seems like its a feature unless youre running some ungodly number of LEDs

What would be really helpful is if you draw a schematic or snap a pic of your setup...
 
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