reef-pi :: An opensource reef tank controller based on Raspberry Pi.

[Bigtrout]

The load is only 6.7 amps (rated by the manufacturer, LG) at start up, the Hitachi compressor is 1100 watts @ 220~240 volts, so that's approx 5 amps, mostly our mains voltage hovers between 190-230 volts, so should be well in range of the relay, rated @10 amps 250 volts.

A compressor is a heavily inductive load with quite a surge on startup. Those relays are rated for 10 amps on a resistive load, and only 3 amps on an inductive load.
If it were me, i would use the small relay on the board to run a better rated relay for the chiller.

 

[stefanm]

A compressor is a heavily inductive load with quite a surge on startup. Those relays are rated for 10 amps on a resistive load, and only 3 amps on an inductive load.
If it were me, i would use the small relay on the board to run a better rated relay for the chiller.

Maybe, but the chiller has a relay on board, shouldn't that be sufficient?

I'm suspecting that the relay module could be faulty? or its PSU maybe not up to the mark (2 amps) I've had the issue return just now, the chiller should have switched on but didn't and I tried to switch the pumps off for feeding and nada, again I rebooted. I'm going to update to 2.3 incase it's a software issue, the ambient temperatures are ok to keep the temperature relatively stable without getting to high.

 

[Bigtrout]

Maybe, but the chiller has a relay on board, shouldn't that be sufficient?

I'm suspecting that the relay module could be faulty? or its PSU maybe not up to the mark (2 amps) I've had the issue return just now, the chiller should have switched on but didn't and I tried to switch the pumps off for feeding and nada, again I rebooted. I'm going to update to 2.3 incase it's a software issue, the ambient temperatures are ok to keep the temperature relatively stable without getting to high.

In a word, no, every relay that the conpressor power goes thru needs to be rated for the compressor load. My educated guess is this chiller is close to 1hp.
Those little relays are nowhere close to being the right relay for that, you said that the chiller is rated at 5amps, with a 6.7amp starting current. Compressors are inductive loads and the relays may be rated at 10amps but thats for a pure resistive load like a heater. The spec sheet on the songle relays, rates them at 3amps max on an inductive load. You are more than double that on start up...when selecting relays for repetitive use the general idea is to pick one thats rated double of the load you are switching, to prolong relay life.
Either use that relay to run another relay rated for a 1hp motor, or if there is a schematic it may be possible to control it with reef pi thru the chillers own controls.

 

[16Reefer170]

@Bigtrout i just tested out the 2.3 builds, i think its fixed now. Can you test it out(just download the debian file and re-install) when you have time, and let me know if its still not working.

There was two different issues intermingled.. one involving the core pca9685 driver (i2c stuff), and the other around the reef-pi<-> pca9685 integration that was modified during the HAL work,.

I downloaded and installed the 2.3 build when you first posted it. When I try wget it agin, it replies “the file is. Fully retrieved; nothing to do”. Any thoughts?

 

[Bigtrout]

I downloaded and installed the 2.3 build when you first posted it. When I try wget it agin, it replies “the file is. Fully retrieved; nothing to do”. Any thoughts?

Type in rm <filename of the downloaded reef pi> and it will erase it and you can wget it again

 

[stefanm]

In a word, no, every relay that the conpressor power goes thru needs to be rated for the compressor load. My educated guess is this chiller is close to 1hp.
Those little relays are nowhere close to being the right relay for that, you said that the chiller is rated at 5amps, with a 6.7amp starting current. Compressors are inductive loads and the relays may be rated at 10amps but thats for a pure resistive load like a heater. The spec sheet on the songle relays, rates them at 3amps max on an inductive load. You are more than double that on start up...when selecting relays for repetitive use the general idea is to pick one thats rated double of the load you are switching, to prolong relay life.
Either use that relay to run another relay rated for a 1hp motor, or if there is a schematic it may be possible to control it with reef pi thru the chillers own controls.

Understood, I can get a single relay module rated at 30 amps also states 1 hp, I'll order it today and should reach by Monday, just when I thought my fiddling had finished!

 

[Bigtrout]

Understood, I can get a single relay module rated at 30 amps also states 1 hp, I'll order it today and should reach by Monday, just when I thought my fiddling had finished!

Yeah, chillers are of a special case, but as an industrial control tech, I would rather see you do it safely and properly.

Maybe I should do a writeup about what the recommended adj bar and 8 channel relays can and cannot be used for

 

[Ranjib]

Yeah, chillers are of a special case, but as an industrial control tech, I would rather see you do it safely and properly.

Maybe I should do a writeup about what the recommended adj bar and 8 channel relays can and cannot be used for

Yes please :-) . Happy to put it in website , and any other recommendations if it’s consolidate

 

[stefanm]

Yeah, chillers are of a special case, but as an industrial control tech, I would rather see you do it safely and properly.

Maybe I should do a writeup about what the recommended adj bar and 8 channel relays can and cannot be used for

I have this relay from my old temperature controller. It's especially for ac's, thinking I could use this, it requires 12vdc to energise the coil, not sure if I could use the pi output as the trigger, I probably wouldn't want to as there's no protection, however I could just trigger it from the existing relay once I figure how to wire it up.

 

[Bigtrout]

I have this relay from my old temperature controller. It's especially for ac's, thinking I could use this, it requires 12vdc to energise the coil, not sure if I could use the pi output as the trigger, I probably wouldn't want to as there's no protection, however I could just trigger it from the existing relay once I figure how to wire it up.

Thats a much better relay for switching a chiller, it has motor rated contacts.
I would isolate the pi...use the pi to trgger your relay board...run the 12volts dc thru the relay board relay contacts...pi triggers the small relay...the small relay triggers your chiller relay.

 

[Ranjib]

Thats a much better relay for switching a chiller, it has motor rated contacts.
I would isolate the pi...use the pi to trgger your relay board...run the 12volts dc thru the relay board relay contacts...pi triggers the small relay...the small relay triggers your chiller relay.

Uln2803a should also work ,

 

[stefanm]

Ready to do this now, wish me luck, lol..

 

[stefanm]

Oops double post

 

[stefanm]

Ok done, expected job time 25 minutes, actual 90 minutes, that was actually quite painful lying on the floor with crappy eyes, I could and should have just removed the relay box and worked on a table, that would have been so much easier. I really don't know how People manage with sumps under their tanks!

Anyway I switched everything back on and the chiller didn't come on, I toggled the switch under equipment a few times, then bingo it came on, I do have the temperature control to check at 50 second intervals, not sure if that's the reason for the delay or not. I'll be out on a job site in the morning, so won't be able to tell until the afternoon, it's night time now and ambient temperature is 23°c, may drop to 21°c as my tank is out doors I doubt the chiller would kick on tonight.

Fingers crossed...

 

[DirtDiggler2823]

Finally replaced the splitter that my temperature probes were hanging off of, but the results are the same. Errors when I open the web interface, followed by the probes totally dropping out of the configuration. If I reboot, they come back for a minute or two before dropping out again. I'll try to just go with one and see what happens.

 

[DirtDiggler2823]

Finally replaced the splitter that my temperature probes were hanging off of, but the results are the same. Errors when I open the web interface, followed by the probes totally dropping out of the configuration. If I reboot, they come back for a minute or two before dropping out again. I'll try to just go with one and see what happens.

Same result with only one probe running. Something is wrong here. Has anyone run into this? Do I need to rebuild my reef-pi?

 

[Ranjib]

Same result with only one probe running. Something is wrong here. Has anyone run into this? Do I need to rebuild my reef-pi?

we have seen this only with builds having bad probes or wirings/connector issues.

 

[stefanm]

Same result with only one probe running. Something is wrong here. Has anyone run into this? Do I need to rebuild my reef-pi?

Check you've wired it correctly and have good contacts, seems like the pull up resistor is either in the wrong place or value, I had this issue myself with an Arduino build and the resistor had a poor connection, resoldered it and working the same probe is on my pi now.

 

[PRock]

Hey guys, I've been playing around with the reef-pi and downloaded the source from Github and just started looking through it. I've got a go module written up to talk to TP-Link Smart Powerstrips (well, any of the TP-Link/Kasa plugs) via TCP and was wondering where I should look in the code to wire it up as a power device so the reef-pi can access it? The TP-Link devices also provide power usage data so getting that hooked up as something to track in stats would be awesome as well.

 

[Ranjib]

Hey guys, I've been playing around with the reef-pi and downloaded the source from Github and just started looking through it. I've got a go module written up to talk to TP-Link Smart Powerstrips (well, any of the TP-Link/Kasa plugs) via TCP and was wondering where I should look in the code to wire it up as a power device so the reef-pi can access it? The TP-Link devices also provide power usage data so getting that hooked up as something to track in stats would be awesome as well.

:-) Thats awesome.
you can implement a TP-Link Smart PowerStrip driver that implements hal.OutputDriver and hal.AnalogIn, the first one can be used to control the outlets, and the second one can be used to read the usage data.. join the slack channel (link on the very first post of this thread, or in the website) and we can touch base there. most of the development chatter happens there.