Ensy AHU 700 integration

[02dag]

I have managed to get hold of all the register values for my ventilation and it is using modbus. The register values is attached.

I am thinking of making a json-file for this and preferrably manage to read some temperatures and force the fan when certain conditions are met. I have some very large windows in my house and the temperature in the living room can be quite high. This starts to become a problem this time of year, and I wanted to control this by LM instead of a second display attached to the ventilation. As long as the temperature outside is lower than let us say 24 degrees the ventilation can provide cooler air to enter the house.

The guy from ensy said this regarding connectivity:

You need an Ensy modbus interface card which is connected to the modbus rs 485 terminal on the room PLS nd the communication card in the Ensy.

By further investigation he also said the this is because:

If you connect your LM to an Ensy aggregate, you will not be able to communicate with it. The ensy modbus interface card acts as a translator between the aggregates internal protocol and the Modbus RTU protocol. The main board in the aggregate will then "see" the LM as display number two. You will also not have any problems with Master/slave(It cannot be two masters in the same network. You have to buy this interface card to make this work.
 
Is there a way around buying this you think? I have seen that to upgrade the firmware on the Ensy it is enough to attach a pc directly to the port for the second display. However you have to have a special cable, but I beleived until now that this was due to USB on the pc and RJ11 on the display port. If that is so it wouldnt be a problem to connect the LM directly either. On the other hand if there is some magic going on in that cable, it is probably necessary to get that interface card.

Will the LM manage to handle the master/slave situation? I thought the Modbus could exist of several devices talking on the bus at the same time.

[02dag]

Here is the update with the json-file. Not yet tested since I have not connected to the ventilation yet. Since this is my first json-file ever there could be some errors in it. I have tried to make it based on the excel sheet I got from the manufacturer. There are noe value multipliers, this have to be checked when I finally connect to the system.

QUESTION: I have a multisensor installed on the modbus today. It has the addresses 0,1 and 6 for humidity, temp and illumination. Will this multisensor interfere with the ventilation system if I just hook that up as well?

[zoltan]

Is there a way around buying this you think? I have seen that to upgrade the firmware on the Ensy it is enough to attach a pc directly to the port for the second display. However you have to have a special cable, but I beleived until now that this was due to USB on the pc and RJ11 on the display port. If that is so it wouldnt be a problem to connect the LM directly either. On the other hand if there is some magic going on in that cable, it is probably necessary to get that interface card.

Will the LM manage to handle the master/slave situation? I thought the Modbus could exist of several devices talking on the bus at the same time.

 
In some situations it's "only" a level converter, but sometimes it is a complicated (encrypted) proprietary protocol to lock the costumer in. Sometimes the tech just don't know what they are talking about, most of them do only plug-n-play installations.

It is entirely possible if you have a will, knowledge and the needed tools, but I guess you are not expert in reverse engineering various protocol.

So, if you have the will, here is what should be done first:
a) - Identify the communication port and the type of underlying electrical protocol (RS232, RS458/422, LON, etc..)
b) - get a suitable interface to sniff the communication bus (logic analyzer, bus interface to PC, ...)
c) - get a recording of a communication with known commands and values (temperature, speed, various % values, commands from control unit, etc...)
d) - try to find a correlation between known values and the recorded communication
e) - write a driver, test, debug and post here

I believe there are people on this forum who can help you, but first you need to provide the basics from point a). Take a few good picture of the control board and the remote control board electronics. The chips on the board must have visible markings. From that it is possible to get some conclusions about electrical protocol. Mark the communication port if its not marked on the board.

Edit: DO NOT CONNECT anything until you verified the electrical protocol! It can be a painful experience (read - dead LM and/or dead Ensy board)

br, Zoltan

[02dag]

Thank you for the response Zoltan, however it looks like a lot of work to get this done. The easy way out of this is of course just check the temp in the living room and start forced fan ventilation when the temp is too high. The ensy comes with connectors made for doing a few things, like increased supply air, and decreased extract air when kitchen fan is working and so on. Should be enough to use one of the analog outputs and a relay to make this happen. But sooo boring!!

[admin]

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