(12.04.2019, 12:57)02dag Wrote: 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