Moxa MD-119-X1 [36/44] Connecting to the display

MD-119 HW Manual Display UART Command

C-2

Connecting to the Display

You need to use a serial cable to connect the computer to the serial port, marked RS-232/422/485 on the

MD-119 display. Then you can use the program to communicate with the MD-119.

UART Software Configuration

Date Rate

The date rate has been set at 9600 bits/second for data transmission and receive.

Data Format

Data shall be transmitted with no parity, 8 data bits, 1 start bit, and 1 stop bit.

UART Command Format

The basic message format is listed below:

Byte # 0 1 2,3,4 5 6 7, etc 7+LEN

ATTN ADDR CMD LEN IHCHK DATA IDCHK

The minimal message size is 7 bytes, and the maximal message size is 82 bytes, consistent with 61162-1.

Command Format Description

ATTN (Attention)

This byte is used to identify a start of message, and it can be one of three values:

ATTN Description

0x07 Command (ASCII BELL)

0x06 Acknowledge (ASCII ACK)

0x15 Negative Acknowledge (ASCII NAK)

A device shall send a command using the 0x07 Attention Code. The unit will respond to the command with either

an ACK if the command completed successfully, or a NAK if the command failed.

ADDR (Address)

This byte is used to specify a particular unit to receive a Command and to identify the unit responding (ACK or NAK)

to a Command. All units will support the broadcast address. The factory default address is 0.

The Address field shall have the following values:

ADDR Description

0xFF

Broadcast - Addressed to all units

0x00 to 0x0F

Address of a specific unit

(max of 16 units)