4
For all aspects other than serial data transmission the
transmitter is set up as shown in the Operating Instructions
(IM/ZMT). Unless otherwise requested, the instrument is
despatched with a transmission rate of 9600 baud and
transmission line termination resistors linked-out. If these
settings are unsuitable, refer to Section 5.1.
5.1
Termination Resistors
and Baud Rate Settings – Fig. 5.1
5.1.1
Termination Resistors
For long transmission lines, termination resistors are
required on the last ZMT Analyzer in the chain and at the host
computer/computer terminal. Under normal operating
conditions the resistors are required at the last ZMT receive
inputs only – see Fig. 4.1. The analyzer’s resistors are
selected using plug-in links – see Fig. 5.1.
Switch off the supply and gain access to the Serial Output
board in Output Module 3 – see
IM/ZMT, Section 6.2. Set the
termination resistor links as shown in Fig. 5.1.
5.1.2
Hardware Baud Rate Setting
To set the Baud rate to the required speed, set the plug-in link
as shown in Fig. 5.1
The protocol used is based on ANSI-X3.28-1976-2.5-A4 and
is used for master (host computer) to slave (ZMT Analyzer)
systems. This is the
recommended protocol for use with
supervisory systems
such as ABB Kent-Taylor PC30. The
Protocol is:
Start transmission (STX) – Command – Identification…
…End transmission (ETX) – see Figs. 8.1 to 8.6.
Transmissions of commands and processing of the
subsequent replies must be incorporated into the host
computer programme.
Fig. 5.1 Termination Resistor and Baud Rate Links
5
SETTING UP
6
PROTOCOL
IN
1
12
6
7
1
12
6
7
OUT
9
8
16
1
1200
9600
4800
2400
Baud Rate Links
Termination Resistors
Summary of Contents for AnalyzeIT ZMT Series
Page 18: ...16 NOTES ...
