Introduction; Preparation; Company Standard Settings - ABB COMMANDER 300 Operating Instructions Manual

1 INTRODUCTION

The C300 Series of controllers is extended
by the addition
communication option
addressing and
computer terminal or host computer.
The RS422/485 communication standard is
used with the following logic levels:
a) for logic '1' (MARK condition or IDLE
state) the 'A' terminal of the transmitter is
negative (0V) with respect to the 'B'
terminal (+5V)
b) for logic '0' (SPACE condition or ACTIVE
state) the 'A' terminal of the transmitter is
positive (+5V) with respect to the 'B'
terminal (0V).
Parity is used for simple error checking. The
parity bit is a one-bit code which is
transmitted in addition
character. It can detect only one error per
character, since two errors may cancel out.
Parity is calculated by finding the sum of
logic '1's in the character and either:
a) setting the parity bit to logic '1' if the sum
is odd, or logic '0' if the sum is even,
when using even parity
or
b) setting the parity bit to logic '0' if the sum
is odd, or logic '1' if the sum is even,
when using odd parity.
The block check character (BCC) is an
additional form of checking and is the
arithmetic sum of all the characters in a
complete message (excluding parity bits) –
see Appendix A3 on page 28.
detection is achieved by comparison of the
BCC's of the transmitted and received
messages.
2
of a serial
which allows
reprogramming via
to the ASCII

2 PREPARATION

The procedure is similar to that described in
data
the Operating Instructions (IM/C300) with
additions as detailed in this section.
a

2.1 Company Standard Settings

Only those parameters detailed on the
customer order are programmed at the
factory. If any parameters are unsuitable for
the application they can be reprogrammed –
see Section 7 of the Operating Instructions
(IM/C300). Serial data programming details
are to be found in Section 7 of this manual.
Standard parameter settings for the serial
data programme are as follows:
Instrument Identity
Parity
Block Check
Character (BCC)
Transmission Rate
C
Error
Fig. 4.1 Serial Connections
A C B
Instrument
Viewed
from Rear
Common
8
Rx+
9
Rx–
10
Tx+
11
12
Tx–
01
odd parity
BCC on
9600 baud.