TCP Modbus - Printable Version

TCP Modbus - Printable Version

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+--- Thread: TCP Modbus (/showthread.php?tid=688)

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TCP Modbus - leondias - 21.03.2017

Hello,

I'm trying to make a connection with Modbus TCP slave device.

I tried to do so with scripts (you can see it below) and visual mapper.
In visual mapper I tried many different combinations in device profile, but couldn't get right value:

Code:
{ "name": "Input 1", "bus_datatype": "float16", "type": "register", "address": 128, "datatype": "float16", "value_multiplier": 1, "units": " C" },

{ "name": "Input 1", "bus_datatype": "uint16", "type": "register", "address": 128, "datatype": "float16", "value_multiplier": 1, "units": " C" },

{ "name": "Input 1", "bus_datatype": "int16", "type": "register", "address": 128, "datatype": "int16", "value_multiplier": 1, "units": " C" }

and etc..

Full script (IP address of device is corrent - 192.168.1.210, port - 502, slave ID - 20):

Code:
require('luamodbus')

if not mb then

    mb = luamodbus.tcp()

    mb:open('192.168.1.210')

    mb:connect()

end

-- verbose output and select slave number 10

mb:setdebug(true)

mb:setslave(20)

-- read input from reg 1 to 5, get slave-specific data

local result = mb:readregistervalue(128, dt.float16)

grp.write('14/1/0', result, dt.float16)

local value = mb:reportslaveid()

alert(value)

-- close serial connection

mb:close()

RE: TCP Modbus - admin - 21.03.2017

Are you sure it's float16 on ModBus side? float16 is KNX-specific datatype and I've only seen one ModBus AC unit which has it as register value. Also, second mb:readregistervalue() parameter must be a string, not a dt.something. Do you have documentation for your ModBus device?

RE: TCP Modbus - leondias - 21.03.2017

(21.03.2017, 14:34)admin Wrote: Are you sure it's float16 on ModBus side? float16 is KNX-specific datatype and I've only seen one ModBus AC unit which has it as register value. Also, second mb:readregistervalue() parameter must be a string, not a dt.something. Do you have documentation for your ModBus device?

Yes, here it is

Now I try to read jus a outdoor temp. to get started. In the documentation its 129 address, but I'm trying with all 128, 129 and 130 to be sure Smile

RE: TCP Modbus - admin - 21.03.2017

Datatype should be "float32", you also might have to set "read_swap" property as stated here: http://openrb.com/docs/modbus.htm

RE: TCP Modbus - leondias - 21.03.2017

(21.03.2017, 14:42)admin Wrote: Datatype should be "float32", you also might have to set "read_swap" property as stated here: http://openrb.com/docs/modbus.htm

Can I use this property in script or only in visual mapper?
If yes, how?

RE: TCP Modbus - admin - 21.03.2017

You can use in both, but first you need to figure out correct byte/word order by using this in your script:

Code:
v1 = mb:readregistervalue(128, 'float32', 'n')

v2 = mb:readregistervalue(128, 'float32', 'b')

v3 = mb:readregistervalue(128, 'float32', 'w')

v4 = mb:readregistervalue(128, 'float32', 'bw')

log(v1, v2, v3, v4)

One of the values in logs should be correct.

RE: TCP Modbus - leondias - 22.03.2017

Thanks a lot! It works!

RE: TCP Modbus - unaxboy - 13.11.2017

(22.03.2017, 07:38)leondias Wrote: Thanks a lot! It works!

Hi leondias, I also trying to config Ping2. Can you share json with me?)