(18.11.2020, 09:11)Rick Wrote: Hi~, I am connecting another brand of RS485 air conditioner panel via LM. Each time it is triggered, this panel will send out 16 bytes of data.
  It can be polished from the picture, I read 16-bit data from the 485 bus every time. But there are other panel devices on the bus. These devices transmit different amounts of data after being triggered.
  As a result, some of the 16 bytes of data I received may not be commands from the air conditioner panel, so I cannot make a judgment.
  For the data received by the LM, I need to input the data in (AD BD 0D 1A 06 03 05 42 20 01 28) to make a judgment. For example, the value of 20. How to extract 20 and then judge and execute the corresponding operation?

(18.11.2020, 09:27)Daniel. Wrote: The best would be to contact the AC manufacture and ask for protocol documentation.

(18.11.2020, 09:27)Daniel. Wrote: The best would be to contact the AC manufacture and ask for protocol documentation.

(18.11.2020, 09:41)Daniel. Wrote: Each product must have a address which is one of the byte in the string, probably the first.

(18.11.2020, 09:46)admin Wrote: Are you sure that each frame has a fixed length of 16 bytes? From your logs it seems that the length can be different.

(18.11.2020, 09:49)Rick Wrote:

(18.11.2020, 09:41)Daniel. Wrote: Each product must have a address which is one of the byte in the string, probably the first.

YES, for example, when LM receives a string of 20 bytes of data, I only need the consecutive 16 bytes. How can I extract these 16 bytes?

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(18.11.2020, 09:46)admin Wrote: Are you sure that each frame has a fixed length of 16 bytes? From your logs it seems that the length can be different.

YES,the air conditioner panel I need to receive is 16 bytes each time. But sometimes this panel will actively report more than 16 bytes of data, and I will ignore this data.

(18.11.2020, 10:58)admin Wrote: Can you provide documentation on the protocol? From your logs ab bd is not in same place.

(18.11.2020, 11:20)admin Wrote: How often is data sent on the bus? Can there be long delays between packets?

(19.11.2020, 07:44)admin Wrote: Try this as a resident script. Edit serial.open with correct port name and settings.

Code:

if not port then
  require('serial')

  port = serial.open(...)

  function read()
    local buf = {}

    while true do
      local timeout = #buf > 0 and 0.5 or 15
      local char = port:read(1, timeout)
     
      if char then
        buf[ #buf + 1 ] = char:byte()
      else
        return buf
      end
    end
  end
end

res = read()
log(res)
if #res == 16 then
  -- process 16 bytes of data
end

Return value for read function is a table containing bytes that have been read converted to numbers. It assumes that there's at least 0.5 seconds between consecutive messages. You can edit the timeout value to suit your needs.

(19.11.2020, 09:32)Rick Wrote:

(19.11.2020, 07:44)admin Wrote: Try this as a resident script. Edit serial.open with correct port name and settings.

Code:

if not port then
  require('serial')

  port = serial.open(...)

  function read()
    local buf = {}

    while true do
      local timeout = #buf > 0 and 0.5 or 15
      local char = port:read(1, timeout)
     
      if char then
        buf[ #buf + 1 ] = char:byte()
      else
        return buf
      end
    end
  end
end

res = read()
log(res)
if #res == 16 then
  -- process 16 bytes of data
end

Return value for read function is a table containing bytes that have been read converted to numbers. It assumes that there's at least 0.5 seconds between consecutive messages. You can edit the timeout value to suit your needs.

THANKS,I will try this.

(19.11.2020, 09:36)Daniel. Wrote: Your device mots likely is overloaded and it keeps rebooting.

(19.11.2020, 09:56)Daniel. Wrote: Install the System Load app and see what process is eating your LM

(19.11.2020, 10:03)Daniel. Wrote: In the app store there is app to monitor ruining processes on LM.

(19.11.2020, 10:03)Rick Wrote:

(19.11.2020, 10:03)Daniel. Wrote: In the app store there is app to monitor ruining processes on LM.

Got it!

(19.11.2020, 07:44)admin Wrote: Try this as a resident script. Edit serial.open with correct port name and settings.

Code:

if not port then
  require('serial')

  port = serial.open(...)

  function read()
    local buf = {}

    while true do
      local timeout = #buf > 0 and 0.5 or 15
      local char = port:read(1, timeout)
     
      if char then
        buf[ #buf + 1 ] = char:byte()
      else
        return buf
      end
    end
  end
end

res = read()
log(res)
if #res == 16 then
  -- process 16 bytes of data
end

Return value for read function is a table containing bytes that have been read converted to numbers. It assumes that there's at least 0.5 seconds between consecutive messages. You can edit the timeout value to suit your needs.