Connect your stack to a RS-485, multi-drop serial network. Set your baud rate (speed) and whether you want a network termination resistor via properties in the blueprint you create using the Stackbuilder authoring tool. There are many message protocols that run on RS-485 networks, for example MODBUS, MODBUS RTU, DMX512, and proprietary machine specific formats. Use built-in software blocks, or software blocks you create using Python scripting in Stackbuilder, to parse and send messages.
To set properties in Stackbuilder: Select the RS-485 block by clicking on it once. Click in the “Property Editor” in the bottom right, in the “Initial Value” column for the property you want to edit (if a character or string, use quotes).
RS-485 connector – Looking into back
The A (D-) and B (D+) screw terminals are used to connect to the network.
Block properties and terminals
Type (T) (uuid): Module Type
Version (F) (int): Firmware Version
u_baud (B) (int): Uart baud rate. default 9600 baud.
u_resistor (R) (int): If 1, connect the 120 ohm network terminating resistor. 0 to not connect (default).
“Properties” – in (List or Property Name string): To set property. Send property name, Value. For example [’N’,’netname’].
To get property, just send property name. For example. ’N’
“PResponse” – out (List or True) : On set, responds with True when done.
On get, responds with list. For example [’N’, ‘netname’].
“Send” – in (String, Binary, int): send string to UART, we only send valid ascii portion. Also accept binary raw bytes. Also int < 256. send out as raw byte.
“Receive” – out (String): Single byte received by UART. sent as String.
For the DMX512 message protocol, send [1,100] to the send terminal to generate a 100uS break. Send [2,20] to generate a 20uS mark after break.