Controlling Via Rs232/Net; Introduction; Set-Up; Conventions - Arcam SA20 Custom Installation Notes

Controlling via RS232/NET

Introduction

This document describes the remote control protocol for controlling via the RS232/NET interface.

Set-up

IP control is via port 50000 of the IP address of the unit.

Conventions

„ All hexadecimal numbers begin 0x.
„ Any character in single quotes gives the ASCII equivalent of a hex value.
„ <n> represents an unknown or variable number.

Serial cable specification

The cable is wired as a null modem:
Connector 1 pin Connector 2 pin
2 3
3 2
5 5

Data transfer format

„ Transfer rate: 38,400bps
„ Data format: 8 data bits, 1 stop bit, no parity, no flow control.

Command and response formats

Communication between the remote controller (RC) and the SA10/SA20 takes the form of sequences of bytes, with all commands and responses having the
same basic format. The SA10/SA20 shall always respond to a received command, but may also send messages at other times.
Each transmission by the RC hs the following format:
<St> <Zn> <Cc> <Dl> <Data> <Et>
• St (Start transmission): 0x21 '!'
• Zn (Zone number): see below
• Cc (Command code): the code for the command
• Dl (Data length): the number of data items following this item, excluding the Et
• Data: the parameters for the command
• Et (End transmission): 0x0D
Each response by the SA10/SA20 has the following format:
<St> <Zn> <Cc> <Ac> <Dl> <Data> <Et>
• St (Start transmission): 0x21 '!'
• Zn (Zone number): see "Zone numbers", below
• Cc (Command code): the code for the command
• Ac (Answer code): see "Answer codes", below
• Dl (Data Length): the number of data items following this item, excluding the Et
• Data: the parameters for the response of length n (note that n is limited to 255)
• Et (End transmission): 0x0D
The SA10/SA20 responds to each command from the RC within three seconds. The RC may send further commands before a previous command response has
been received.
Zone numbers
The following zone numbers are defined:
• 0x01 – Zone number 1. (Zone 1 is the master zone. Commands that appear zone-less refer to the master zone)
• 0x02 – Zone number 2
Function
Rx  Tx
Tx  Rx
RS232 Ground
3