Boundless ADDS 6700 Manual download pdf (Page 132)

-DIN,

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- DIN Controllers & Indicators - Product Manual

59305, Issue 7 – March 2014 ASCII Communications Page 127

14 ASCII Communications

This is simple ASCII protocol provides backwards compatibility with some older products.

ASCII is not available in all models in the range. The Modbus protocol is recommended for

future use.

Refer to the relevant Model Group Section for the ASCII and Modbus Application Layer

(parameter address/ident information).

Physical Layer

The Base address, bit rate and character format are configured via the front panel in

Configuration Mode or by using the PC Configurator software.

Physical layer configuration settings possible are:

Data rate: 1200, 2400, 4800 (default), 9600 and 19,200 bps

Parity: Even

Character format: 7 bits per character. + 1 stop bit.

The transmitter must not start transmission until 3 character times have elapsed since

reception of the last character in a message, and must release the transmission line within 3

character times of the last character in a message.

Note:

Three character times = 1.5ms at 19200, 3ms at 9600, 6ms at 4800, 12ms at 2400 and

24ms at 1200 bps.

Device Addressing

The instrument is assigned a device address by the user using the  parameter in

Configuration Mode. The address may be set to any unique value from 1 (default) to 99. This

address is used to recognise ASCII messages intended for this instrument. The instrument

does not respond to messages that do not match the address that has been assigned to it.

Session Layer

The ASCII protocol assumes half duplex communications. The master device initiates all

communication. The master sends a command or query to the addressed slave instrument

and the slave replies with an acknowledgement of the command or the reply to the query.

Messages from the master device may be one of five types:

Type 1: {S}{N}??*

Type 2: {S}{N}{P}{C}* or R{N}{P}{C}*

Type 3: {S}{N}{P}#{DATA}* or R{N}{P}#{DATA}*

Type 4: {S}{N}{P}I* or R{N}{P}I*

Type 5: {S} {N} \ P S S ? *

All characters are in ASCII code. See the following Parameter Key table for details of the

parameters in brackets { }.

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Boundless ADDS 6700 Manual Page 132