@Kocta Interesting!
Are you using frequency ratio control (DR) to limit the compressor speed?
Have you tried Modbus and the 0-10v (I believe they are the only methods listed in the manual)? If so which is working better for you?
Thanks,
Paul
I tried both, you can write to a register but it’s only for about 1 hour then it goes back to normal, you need write again to the register.
If you use an analog signal, it has to be activated in FSV
0V = 50% 32Hz in my case
In mine opinion it is more convenient, but don’t expect to much from it.
Actually, I’m using HA to enable/disable zone depending on ambient temps.
I could also do it through water temps, but I think it would cycle more.
I didn’t realise the limits were so limited, it’s probably not going to help much as ours rarely runs more than 25hz other than initial startup. Thanks for the feedback though, saves me wasting time trying it out.
Hello, I’m interesting in this!
Dear all,
After more testing, it appears that without my reel of wire between the HP and my module, the communication doesn’t go through. So I’ll look into it more deeply before sending any board to anyone 
I don’t want any on-the-field failure!
Cheers,
Guys, it is possible control field settings with this as well ? I have MIM-B19N in indoor unit but some of the NASA protocol messages simply are not working with this.
I’m especially interested in these values:
| 0x4254 | VAR_IN_FSV_2011 | Water Law Auto heating ambient temperature - Max. | ||
|---|---|---|---|---|
| 0x4255 | VAR_IN_FSV_2012 | |||
| 0x4256 | VAR_IN_FSV_2021 | Water Law (WL1-Floor) Temperature auto heating - Max. | ||
| 0x4257 | VAR_IN_FSV_2022 | |||
| 0x4258 | VAR_IN_FSV_2031 | Water Law (WL2-FCU) Temperature auto heating - Max. | ||
| 0x4259 | VAR_IN_FSV_2032 |
Modbus interface module is connected to outdoor unit. I’m using RS485 to USB adapter connected to rPI. I wonder where do you connect the USB reader to use with NASA link ? It’s connected into control kit (MIM-E03CN) or I also have wifi kit and I’ve seen some connectors there as well. Thx.
Hello, if I understand correctly you can’t access all the fsv you’d like.
I connect the USB<->F3/F4 directly on the E06cn indoor unit.
All the fsv you mentionned are fsv that I’ve already integrated and that I control through home assistant.
cheers
Hi, yes exactly. Not all are available via Modbus interface so your solution sounds better for me. What RS485 to USB adapter do you use ? I have this one so I guess it could work for this as well ?
Thanks.
The F3/F4 RS485, is a modulated RS485, I use a THVD80x0 chip behind a RS232 USB converter. But the PCB I’m finalizing (sounds like it’s an analog filtering issue I’m running in) is implementing exactly that.
Ah, so theoretically my converter could work as well, right ? I just need to disconnect it from Modbus interface module and connect to F3/F4 on control unit ? Mine is using FT232RL chip.
Not exactly, you do use RS485 modbus, but it’s not a modulated modbus. The THVD80x0 chip from TI is doing a very particular job to carry RS485 over a DC line. You could damage your USB-RS485 device if you try to connect it.
Hi Topaz,
I’ve never heard Modbus described that way.
Could you elaborate a bit on what you mean by modulated?
Thanks!
Hello @Bill.Thomson,
I’m glad you asked. It bothered me at first too. I had some time to figure out what was the protocol in use on F3/F4 using the oscilloscope.
Here are snapshots of the THVD80x0 chip datasheet :
As you can see, the USART is D, bits are respecting the RS485 way of operation, but instead of simply applying a differential voltage between A and B, an OOK modulation is applied between the wires. allowing for transport of the data over a DC line (hence allowing data+power over 2 wires), it comes very handy to power remote controller as well as communicating with them.
In hope it made the thing clearer.
Cheers,