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)
