Overview
Allows wired connections between stacks of bricks
Long connections possible (up to 1200m)
Configurable baud rate, parity and stop bits
Can be used in existing RS485 networks
TinkerForge 32 TinkerForge
Product description
Description
The RS485 extension can be used for long cabled communication between stacks. It is the differential RS485 standard used to lengths of up to 1200 m.
For a RS485 bus with bricks, two RS485 Extension and two master bricks are required. Both Master bricks can with a full pile of bricks and brick lets be connected together. It must be a master via USB, Ethernet or Wi-fi is connected to the PC. From programrs view, the RS485 bus completely transparent, i.e. all bricks and can be used exactly the same as if you individually brick lets connected via USB.
It is possible to operate a bus with several RS485 extension must be connected by USB, Ethernet or WIFI (Many-to-one routing).
Modbus RTU is a protocol on the RS485 interface is used. Thus it is possible pile of bricks and brick lets with RS485 extension into an existing Modbus network. It is also possible to communicate directly with a pile via Modbus, e.g. via an embedded device or via a Modbus Gateway.
RS485 Busaufbau
An RS485 bus comprises one master and several slaves. The RS485 Master is the master via USB, Ethernet or WLAN to the brick of the PC is connected to the brick daemon is running. All other master bricks with RS485 extension must not USB, Ethernet or WIFI connection (however, you can use a USB power supply since Master Brick Firmware 1.1.3). Each RS485 Extension has its own address. These addresses must be unique within the buses.
In order to build a RS485 bus must be the RS485 Extension on a master brick are inserted and the master brick via USB, Ethernet or wireless connected to the PC. In the brick viewer should now be a master brick with the recognized RS485 extension can be displayed. The RS485 Extension must now be configured as master or slave as described here.
If all of the RS485 extensions are configured, the overall system to be assembled. Connect the required bricks and brick lets to stack. The master of each stack has the lowest brick (unless all the way down if there is a power supply). The RS485 extension can be inserted at any place above the master. The Verkabele RS485 extensions and set the termination switch of the first and last RS485 extension on the bus to "on".
If the bus is only a few meters long is the cable being used normally no role. If the bus is longer than a few meters, it should be a form of twisted pair cable should be used. Telephone cable has frequently twisted pair of wires. Even better is ethernet cable, twisted together and are normally also shielded. If a cable with twisted-pair is used, it should be the same wire pair for A and B are used and another wire pair for GND.
After everything is plugged together, the system can be started. You must first of all RS485 slaves can be started before the RS485 Master is started, since the RS485 master only directly after the start after the slaves. Now, all the bricks and brick lets the RS 485 buses in the brick viewer can be displayed.
RS485 configuration
To configure a RS485 extension must be assigned a unique address for each RS485 slave defined as well as the baud rate, parity, and number of stop bits for the entire RS485 network can be determined.
If the bus is not really huge is for "Speed" 2000000 (2 Mbit/s), for "Parity None and for "Stop bits" 1. If, however, timeouts can occur and the CRC error counter rapidly then rises should be tested. a lower baud rate For the use of the RS485 extension to an existing Modbus network must these settings with those of other network participants must match.
To configure a RS485 extension as a slave must first be "Slave" as the type is selected, and then an address (1-255).
To configure a RS485 extension as master must first be "Master" as the type is selected, and then a list (separated by commas) to addresses of RS485 slaves can be specified, with which the RS485 Master should communicate.
At the end, must be clicked on "Save RS485 Configuration" in order to save the configuration permanently on the RS485 Extension. Then the Master Brick can be newly started the new configuration to take effect.
RS485 Busmodifikation
If something on the bus needs to be changed, e.g. new bricks or brick lets add, then the affected stack first from its power supply. Once the changes have been made, the stack to its power supply connected. If the stack a RS485 slave, then it must also be restarted associated RS485 Master, as this is only at the start of its associated RS485 Slaves searches and the communication with you. The restart of the RS485 master can be achieved by pressing his Reset button, or by a short disconnect its USB connection.
This text is machine translated.
Keywords
4016139057095, TinkerForge, 32, RS485 Master Extension
