Firmware Confusion

[tbully]

Hello –

I recently (during the off season) updated my 2.3 DC hardware’s firmware to 2.2.1 (1). I did this in response to the device oftentimes falling off the network. While I didn’t see anything in the release notes about this, my problem subsided! Win!

Today I went to start my sprinkler system and noted my master valve (normal 24vac) would not engage.

Looking at my version in the App, it lists the device as Hardware Version: 2.3 – AC.

I’m considering buying a new controller as this one is pretty old (but has been solid). Before I do, could the above be an issue? I just used the os_221_rev1.hex file that’s available to download. I didn’t see a different file for AC vs DC.

Thanks.

[tbully]

BTW, I’ve tested the master valve by using a 24 VAC transformer. It opens and passes water as it should when energized.

[Ray]

The firmware automatically detects your hardware version (AC or DC) so the same os_221_rev1.hex works on both AC and DC-powered OpenSprinkler 2.3.

I’m confused about whether your hardware is AC powered or DC powered. Your first paragraph said ‘DC’, but you said in the App, it shows it’s AC. You can easily check by looking at the controller — does it have a DC label on it? If so, it’s DC. Alternatively, does it have an orange terminal block, or does it have a black power barrel? If orange terminal block, it’s AC; if black power barrel, it’s DC.

[tbully]

I’m confused as well. 🙂 (Thanks for the quick response)

I have a DC label and using the original DC supply. I checked voltage on the supply and it’s within spec.

The app is clearly reporting 2.2.1 (1) AC.

I can reapply the FW if you think it’d help!

[tbully]

I reapplied the FW for the heck of it.

During boot, I briefly see v2.3 AC as it boots.

I have the DC label and the black barrel connector.

[tbully]

Tried a few older FW versions as well. Still detects as AC during boot.

[Ray]

If it says AC, but the controller itself has a DC label, then something is damaged — the firmware uses the information stored in a EEPROM on the controller to detect whether it’s AC or DC. If that chip is damaged, it won’t be able to read the DC information, and by default it will treat it as AC.

You mentioned using a 24VAC transformer — are you aware that you should NEVER plug in a 24VAC transformer to a DC powered controller? The DC-powered controller only accepts DC power adapter, up to 12VDC. A 24VAC transformer will fry some components in the controller for sure.

[tbully]

Thanks for the direction. I’m guessing something is messed up in the EEPROM. I do have some experience with microcontrollers, etc. Any (reasonable) chance of me digging in to diagnose that?

🙂 Very aware of putting 24 VAC on something that’s not designed for it would create a bad day for the device. I was just highlighting one of the steps I ran to test (using a 24VAC transformer to actuate the solenoid designed for such – completely isolated from the rest of the system – other than the water lines themselves, I suppose. ha!)

As an update, I read several pages in to this forum where you mentioned that anything up to 12vdc would be safe for the frontend circuitry. I used a 12vdc 1amp supply and this was able to open and hold the valve. Using a scope, I watched the capacitor you use for the inrush demand (awesome design, btw) and saw no ~22v charge. I guess this is expected as it thinks it’s an AC controller. So I view this as a temporary workaround.

Happy to tinker/test if you can help. Otherwise, I’ll consider ~8 years a decent service life and order new, etc.

Thanks again.

[Ray]

I suggest that you submit a support ticket at:
support.opensprinkler.com
with some basic information, and send your controller back to us so we can check and reflash the EEPROM for you so that it will recognize it as DC again. Without it being recognized as DC, the voltage booster circuit won’t engage and therefore it won’t be able to energize the valves with low-voltage power adapter.

But you are right that you can actually use 12VDC to power the controller and if it is able to energize the valves, then you can continue doing that. Technically 12VDC is a bit low for producing inrush current, while a bit high for providing holding current, but I’ve seen people using it for years without problem. So if this works for you you can continue using it.

The design of DC-powered controller is optimized for providing the right currents for both inrush and holding. It produces a boosted voltage about 21VDC to energize the valves. Given that a typical 24VAC valve has a resistance of about 35ohm, this corresponds to 600mA inrush current, which matches most valve’s electric spec. Then it lowers the voltage to the input voltage (7.5VDC), corresponding to about 200mA holding current, which is typical.

[tbully]

I appreciate your offer to have a look. Unfortunately, we’re quickly hitting watering season. Additionally, this unit has worked flawlessly for years and perhaps it’s time for me to just get a new one from you. This would allow me to continue watering while the new one ships.

I was just hoping that I could possibly have a look at the eeprom and potentially fix it myself. It’s not that big of a deal, however.

Thanks again for the help here.

[Author]

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