TRB145 Serial Utilities

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Main Page > TRB Gateways > TRB145 > TRB145 Manual > TRB145 WebUI > TRB145 Services section > TRB145 Serial Utilities

The information in this page is updated in accordance with firmware version TRB1_R_00.07.04.
Note: RS485 services were merged and moved to Serial Utilities page from FW version TRB1_R_00.07.03.

Summary

The Serial Utilities page is used to make serial communication configurations of different types.

To make a new serial configuration instance select a serial type from the left-hand navigation menu. In the next page enter a custom name for the new config, select a serial device and click the Add button.

Example from the Modem Configuration page:

Networking rutos manual serial utilities add new instance default rs485 v1.png

Then, click the Edit button next to the instance:

Networking rutos manual serial utilities edit config default rs485 v1.png

This manual page provides an overview of the Serial Utilities page in TRB145 devices.

General information

RS485


Connector pinout


Below is a depiction of the RS485 connector pins:

RS485 connector pinout
Trb145 rs485 pinout v1.png
Pin Name Description
1 D_N Driver negative signal
2 R_N Receiver negative signal
3 GND Device ground
4 D_P Driver positive signal
5 R_P Receiver positive signal
6 NC Power input 9-30 VDC filler text

Cable type


Recommended cable parameters:

PARAMETER VALUE
Cable Type 22-24 AWG, 2 – pair (used for full-duplex networks ) or 1-pair (used for half duplex networks). One addtitional wire for ground connection is needed
Characteristic cable Impedance 120 Ω @ 1MHz
Capacitance (conductor to conductor) 36 pF/m
Propagation Velocity 78% (1.3 ns/ft)

Maximum data rate vs. transmission line length


The RS485 standard can be used for network lengths up to 1200 meters, but the maximum usable data rate decreases as the transmission length increases. A device operating at the maximum data transfer rate (10 Mbps) is limited to a transmission length of about 12 meters, while a distance up to 1200 meters can be achieved at 100 Kbps. A rough relation between maximum transmission length and data rate can be calculated using this approximation:

Services rs485 formula.PNG

Where:

  • Lmax - maximum cable length in meters.
  • DR - maximum data rate in bits per second.

Twisted pair is the preferred cable type for RS485 networks. Twisted pair cables pick up noise and other electromagnetically induced voltages as common mode signals, which are rejected by the differential receivers.

2-Wire and 4-Wire Networks


Below is an example of a 4-wire network electrical connection. There are 3 devices shown in the example. One of the devices is the "master" and other two are "slaves". Termination resistors (120 Ω each) are placed at each cable end. Four-wire networks consists of one master with its transmitter connected to each of the slaves' receivers on one twisted pair. The slave transmitters are all connected to the master receiver on a second twisted pair:

Services rs485 4wire v2.PNG

Example 2-wire network electrical connection: to enable a 2-wire RS485 configuration you need to connect D_P to R_P and D_N to R_N on the device’s RS485 socket. Termination resistors are placed at each cable end (120 Ω each):

Services rs485 2wire v2.PNG

Modem Control

The Modem serial type is used to manage modem functionality which could be accessed using shell interface. For this purpose you may want use CR/LF (Carriage Return, Line Feed) capable applications like PuTTY on Windows and microcom, minicom, cutecom or similar applications on Linux.

Networking rutos manual serial utilities modem control default rs485 v1.png

Field Value Description
Enable off | on; default: off Turns the instance on or off.
Name string; default: none Instance name, generated by the user when first creating the configuration.
Device RS485; default: RS485 Specifies which serial port will be used for serial communication.
Baud rate integer [300..3000000]; default: 9600 Data rate for serial data transmission (in bits per second (bps)).
Data bits 7 | 8; default: 8 Number of data bits for each character.
Stop bits 1 | 2; default: 1 Stop bits sent at the end of every character allow the receiving signal hardware to detect the end of a character and to resynchronise with the character stream. Electronic devices usually use one stop bit. Two stop bits are required if slow electromechanical devices are used.
Parity None | Odd | Even | Mark | Space; default: None In serial transmission, parity is a method of detecting errors. An extra data bit is sent with each data character, arranged so that the number of 1 bits in each character, including the parity bit, is always odd or always even. If a byte is received with the wrong number of 1s, then it must have been corrupted. However, an even number of errors can pass the parity check.
  • None (N) - no parity method is used.
  • Odd (O) - the parity bit is set so that the number of "logical ones (1s)" has to be odd.
  • Even (E) - the parity bit is set so that the number of "logical ones (1s)" has to be even.
Flow control None; default: None In many circumstances a transmitter might be able to send data faster than the receiver is able to process it. To cope with this, serial lines often incorporate a "handshaking" method, usually distinguished between hardware and software handshaking.
Mode Partial control | Full control; default: Partial control Specifies modem control mode.
  • Partial control- enables modem control with AT commands, mobile connection will be controlled by RUTOS.
  • Full control- enables modem control with AT commands, mobile connection will be controlled by user.
RS485: Full Duplex off | on; default: off Turns Full Duplex mode on or off. This option is available only on the RS485 device.

Console

Console mode requires no further configuration than the settings above and is used as a direct-access method to the device's shell interface. For this purpose you may want use such applications as PuTTY on Windows and microcom, minicom, picocom or similar applications on Linux.

Networking rutos manual serial utilities console default rs485 v1.png

Field Value Description
Enable off | on; default: off Turns the instance on or off.
Name string; default: none Instance name, generated by the user when first creating the configuration.
Device RS485; default: RS485 Specifies which serial port will be used for serial communication.
Baud rate integer [300..3000000]; default: 9600 Data rate for serial data transmission (in bits per second (bps)).
Data bits 7 | 8; default: 8 Number of data bits for each character.
Stop bits 1 | 2; default: 1 Stop bits sent at the end of every character allow the receiving signal hardware to detect the end of a character and to resynchronize with the character stream. Electronic devices usually use one stop bit. Two stop bits are required if slow electromechanical devices are used.
Parity None | Odd | Even | Mark | Space; default: None In serial transmission, parity is a method of detecting errors. An extra data bit is sent with each data character, arranged so that the number of 1 bits in each character, including the parity bit, is always odd or always even. If a byte is received with the wrong number of 1s, then it must have been corrupted. However, an even number of errors can pass the parity check.
  • None (N) - no parity method is used.
  • Odd (O) - the parity bit is set so that the number of "logical ones (1s)" has to be odd.
  • Even (E) - the parity bit is set so that the number of "logical ones (1s)" has to be even.
Flow control None; default: None In many circumstances a transmitter might be able to send data faster than the receiver is able to process it. To cope with this, serial lines often incorporate a "handshaking" method, usually distinguished between hardware and software handshaking.
RS485: Full Duplex off | on; default: off Turns Full Duplex mode on or off. This option is available only on the RS485 device.

Over IP

The Over IP serial type is used to manage serial connections over a TCP/IP network.

Serial Device Configuration


Configure serial port communication parameters in the Serial Device Configuration section.

Networking rutos manual serial utilities over ip serial default rs485 v1.png

Field Value Description
Enable off | on; default: off Turns the instance on or off.
Name string; default: none Instance name, generated by the user when first creating the configuration.
Device RS485; default: RS485 Specifies which serial port will be used for serial communication.
Baud rate integer [300..3000000]; default: 9600 Data rate for serial data transmission (in bits per second (bps)).
Data bits 7 | 8; default: 8 Number of data bits for each character.
Stop bits 1 | 2; default: 1 Stop bits sent at the end of every character allow the receiving signal hardware to detect the end of a character and to resynchronise with the character stream. Electronic devices usually use one stop bit. Two stop bits are required if slow electromechanical devices are used.
Parity None | Odd | Even | Mark | Space; default: None In serial transmission, parity is a method of detecting errors. An extra data bit is sent with each data character, arranged so that the number of 1 bits in each character, including the parity bit, is always odd or always even. If a byte is received with the wrong number of 1s, then it must have been corrupted. However, an even number of errors can pass the parity check.
  • None (N) - no parity method is used.
  • Odd (O) - the parity bit is set so that the number of "logical ones (1s)" has to be odd.
  • Even (E) - the parity bit is set so that the number of "logical ones (1s)" has to be even.
Flow control None; default: None In many circumstances a transmitter might be able to send data faster than the receiver is able to process it. To cope with this, serial lines often incorporate a "handshaking" method, usually distinguished between hardware and software handshaking.
RS485: Full Duplex off | on; default: off Turns Full Duplex mode on or off. This option is available only on the RS485 device.

Over IP Configuration Settings


You can configure network related parameters of the serial connection in the Over IP Configuration secion.

Networking rutos manual serial utilities over ip configuration v1.png

Field Value Description
Mode Server | Client | Bidirect; default: Server This device's role in the connection:
  • Server - the device waits for incoming connections.
  • Client - the device initiates the connection.
  • Bidirect - acts as client by default but waits for incoming connections at the same time.
Protocol TCP | UDP; default: TCP Protocol used in the communication process.
Raw mode off | on; default; default: off When enabled, all data will be transmitted transparently.
No leading zeros off | on; default: off When checked, indicates that the first hex zeros should be skipped.
Server settings: Port integer [0..65535]; default: none Internal port number used to listen for incoming connections.
Server settings | TCP: Timeout (s) integer [0..32767]; default: 300 Specifies an inactivity time limit (in seconds) after which an inactive clients is disconnected.
Server settings | UDP: Predefined client 1 address ip4; default: none Specifies IP address for predefined connection 1.
Server settings | UDP: Predefined port 1 port; default: none Specifies port number for predefined connection 1.
Server settings | UDP: Predefined client 2 address ip4; default: none Specifies IP address for predefined connection 2.
Server settings | UDP: Predefined port 2 port; default: none Specifies port number for predefined connection 2.
Client settings: Server Address ip | host; default: none IP address or hostname of the server that this client will connect to.
Client settings: Port integer [0..65535]; default: none Server's listening port number.
Client settings: Reconnect interval (s) integer; default: none Time period (in seconds) between reconnection attempts in case a connection fails.
Serial device read time integer [0..1000]; default: none Specifies custom read time for the serial device.
RS485: Full Duplex off | on; default: off Turns Full Duplex mode on or off. This option is available only on the RS485 device.
Server settings | TCP: Max clients integer [1..32]; default: 32 Specifies how many clients are allowed to connect simultaneously.
TCP: TCP echo off | on; default: off Enables software TCP echo.
TCP: Always reconnect off | on; default: off When enabled, a new TCP connection will be made after sending every data package.

IP Filter


The IP Filter section is used for configuring which network is allowed to communicate with the device. You may add a new instance by selecting the Interface and pressing Add.

Networking rutos manual console ip filter.png

Then enter the IP address and save.

Networking rutos manual console ip filter instance.png