User manual

905U Wireless I/O Module User Manual
105S Serial I/O Module
Page 8© October 2001
Chapter One INTRODUCTION
1.1 General
The 905U & 105S range of I/O modules has been designed to provide standard “off-the-shelf”
telemetry functions, for an economical price. Telemetry is the transmission of signals over a long
distance via a medium such as radio or twisted-pair wire. Although the 905U/105S is intended to be
simple in its application, it also provides many sophisticated features. This manual should be read
carefully to ensure that the modules are configured and installed to give reliable performance.
The unit can monitor and control the following types of signals:
Digital on/off signals
Example outputs - motor run, siren on
Example inputs - motor fault, tank overflow, intruder alarm
Analog continuously variable signals (0-20mA)
Example outputs - tank level indication, required motor speed
Example inputs - measured tank level, actual motor speed
Pulse frequency signals
Examples - electricity metering, fluid flow
Internal Status signals
Examples - analog battery voltage, power status, solar panel status and low battery
status.
The unit will monitor the input signals and transmit the signal information by radio or RS485 twisted
pair to another module or modules. At the remote unit, the signals will be reproduced as digital,
analog or pulse output signals. The modules also provide analog set points, so that a digital output may
be configured to turn on and off depending on the value of an analog input. The pulse I/O transmits an
accumulated value and the pulses are reliably recreated at the remote unit regardless of ‘missed’
transmissions. The actual pulse rate is also calculated and is available as a remote analog output.
This manual covers the 905U and 105S modules. We have provided a summary on all products
available in the range, below.
• 905U-1, 905U-2, 905U-3 and 905U-4 modules have radio and serial communications. The
modules differ only in their input/output (I/O) design, and are compatible, i.e. they can be used to
communicate signals to each other in the same network. The 905U is a frequency hopping spread
spectrum 900MHz radio.
• 105S-1, 105S-2, 105S-3 and 105S-4 modules have only serial communications. All other
specifications are as per the 905U-1, 2, 3 & 4 modules. The 105S modules are compatible with