FJ-AC-WMP-1 way to Set Ambient Temp?

we are installing a few of these Fujitsu ducted units and all the wired controllers will be placed in one place but the units will be conditioning different areas… the units have onboard return-duct ambient sensors however the area is high humidity(usinf return sensor requires fan be on continuous which injects humidity when cooling not required) so we want to configure the units to use wired remote sensors from a master, we config the intesis as master and the actual fujitsu controllers as slaves… there is a temperature sensing network already in place for the space which is averaging temperatures and providing to our automation system… what we are looking for essentially is a way to use SET,1:AMBTEMP,250 or similar but of course the WMP gives error… is there a way to enable this? we seee it is available on other devices like the modbus or bacnet control, so seems like we should be able to do it with this if WMP would let us? is there firmware that can let us do this?

Hi Christopher,

Unfortunately, AMBTEMP is in a read-only register as explained in the WMP Protocol document on page 19:

is there no way to get it enabled? it appears to be read / write on the MODBUS / BACNET devices

I don’t think it’s possible and even if you could enable it, you would have to make sure that the Fujitsu device also supported it. I will check with the product experts to see if they know of a way, but I doubt it’s possible.

I’ve confirmed that the register is read-only.

I was looking into this more, the Fujitsu unit should support it… as it supports using the Room temp sensor that is located on the wired remote. this appears to work for both the 2 wire and 3 wire wired controllers which means the ambient temp being used is sent in the data stream from the controller to the indoor unit.

this would not be supported if using an IR based WMP device, fujitsu in their documentation states that in IR-Only installs that you must use the return-duct room sensor, or a fujitsu remote sensor (which essentially plugs in where the return duct sensor is connected on the board).

this is an option for us as well as the Modbus Intesis interface… (shows R/W for the ambient temp in the docs). we have ordered both for testing but both have quite long lead-times right now (understandable in todays world).

we verified that the indoor unit in fact uses the temp sensor in the Master wired remote when multiple wired-remotes are present on one indoor unit. (we can hold the wired remote in our hand and watch the ambient temp quickly rise so we know the unit is using that sensor versus the on-board return-duct.

the units being used in this installation, as well as in my home are ARU12RGLX, and ARU18RGLX. they are 2019 models. the intesis device has no issues controlling them, works like a champ. , easy to use and wi-fi connectivity to it is Solid.

devices have saved me a ton of time and energy with not having to reverse-engineer the fuji protocol and build an interface!. these devices didnt exist in 2007/2008 when I built the interface for my old Chigo minisplits…