Specifications

CHAPTER 4

OPERATION

4-11

DT-203X, DT-105X and DT-110X display series

Transmission block

Address

10h

Control

First

Words

High

Words

Low

Bytes

Data

CRC

Low

CRC

High

Address: The display address

10h: ModBus code. Always 10 in hexadecimal.

Control: Control mode and line number.

First: Position of first character sent.

Words high and Words low: Number of words sent into data.

Bytes: Number of bytes sent into data.

Data: Data sent to display.

CRC low and CRC high: CRC value.

The ModBus protocol allows you to work in two different modes:

1- Direct control: Its necessary to send all characters by the serial line.

2- Code control: Its necessary to send the message number. Use TDL software to edit

messages and store them in Eeprom display’s memory.

4.4.2.1. Display address.

1 Byte.

It is the number that identifies the display on network. Valid range between 00h and

FFh. To modify the display address see 4.3.1 “Modify parameters”.

4.4.2.2. MODBUS code: write n words.

1 Byte.

It is always the value of decimal. 10h.

4.4.2.3. Control

1 Byte.

This byte performs more than one function. If D7 bit is 0, all the characters in ASCII

code must be sent to display. Bits D0-D3 specify in which line the text will begin.

If D7 bit is 1, the number of message must be sent to display. Use TDL software to edit

messages and store them in Eeprom display’s memory.

Direct Control: D7 = 0. Send all the characters in ASCII code.

D0-D3 = Number of first line to place the text received.

Code Control: D7 = 1. Send the number of message.