Serial Port

Serial Port Modes

Embedded "Modbus Master" (for I/O extension)
Embedded "Modbus Slave" (to read I/Os from an external Modbus master)
"Remote" mode
Data parsing from "Scripts"

Serial Port Configuration

serial

In GRD with two serial ports you will be able to configure them individually. Notice that the two serial ports cannot be configured on the same mode.

Mode: Depending on how you are planning to use the GRD/cLAN you will choose on of these modes

Modbus Master: To use the Embedded Modbus master to expand the I/Os
Script: To parse incomming data or send data from the script (only on devices with script programming support)
Modbus Slave: To use the Embedded Modbus slave to read/write the device channels (Physical, Modbus or script)
Remote: to access the serial remotely port using publish/subscript

Data output from MW transparent port: It allows you to configure which serial port can be reached remotely from the broker. Configuring a serial port will force this option to on.

Baud Rate: Serial Port speed (1200, 2400, 4800, 9600, 19200, 38400, 57600, 115200)

Data bits: Can be 7 or 8 bits

Parity: Error checking (none, even, odd)

Flow control: Allows automatic control of communication traffic according to the network availability. It is generally used for massive data transfer to avoid loss of information.

Stop bits: Allows to define the number of stop bits.

Time window and End character

In the "Remote" serial port mode, the device will attempt to group several data before sending the packet through the network; this makes a better use of the bandwidth and reduces communication costs. The implemented criteria for the packet end are the following:

Time window (0…1000ms): once data are received, the device will wait in silence during this period before sending the packet through the network. These criteria incorporate a delay in the transmission of the communication, so care must be taken depending on the serial communication protocol being used.

End character (0…255): It is the end character of a serial stream before sending the data.

If the end character criteria is enabled and the time window is disabled, the device will store the received data for an indefinite time until the configured character is received or the 1000 characters are accumulated.

If both criteria are used, whichever is the earliest will cause data to be sent.

2020-11-20