Hi Forum,
I have a third party device that acts like a modbus rtu.
I would like to connect (integrate) this device into a existing BACnet MSTP ( RS485 ) network.
Can the T3 Nano be used as converter (translator, gateway) between modbus rtu and BACnet MSTP?
If this is not possible. Does somebody knows a cost effective solution?
Thank you
The T3-nano will be a great candidate for your project. It can read the modbus registers over RS485 and report them back to your application over Ethernet using Bacnet protocol, it is depicted at Tab8 in the diagram below. You will need a small program running on the T3-nano to read the modbus parameters and save them as VARS.
10 VAR1 = 2.7.MB_REG100
Where 2 is the ‘Panel ID’ you assign to the Nano and 7 is the subnet modbus ID you assign to your device. 100 is the register you want to read from the modbus device.
You would then read the bacnet object from the T3-nano by referring to XXXXAV1, where XXXX is the bacnet instance of the nano.
You can read more about network programming here:
https://forums.temcocontrols.com/t/network-programming-overview/316
Hello Maurice
But what would be the BACnet address of a T3 variable to be read by an existing BACnet network, or better yet, how to link a T3 variable to a BACnet value analog object.
Maybe the drawing can better explain my question.
I think you are asking about device 5 in the network programming example.
If you give the IO or var or any item a name, T3000 will handle the low level details.
10 VAR1 = OUTTEMP
This will store the value from OUTTEMP, no matter what it is or where it is, into the local panel var1. If this is not working let me know and I will have the team check into it.
All vars are available as bacnet objects directly by external systems without any special programming or settings. Tools → Bacnet Tool lets you see all the bacnet objects on a particular device.
