Chapter 1 - Introduction; Overview - Elpro Technologies 915U-2 User Manual

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Chapter 1 - Introduction

1.1 Overview

The 915U-2 range of I/O modules has been designed to provide standard "off-the-shelf"
telemetry functions, for an economic price. Telemetry is the transmission of data or
signals over a long distance via radio or twisted-pair wire cable.
Although the 915U-2 Series is intended to be simple in its application, it provides many
sophisticated features, which will be explained in the following chapters.
This manual should be read carefully to ensure that the modules are configured and
installed to give reliable performance.
The 915U-2 telemetry module extends the functionality provided by the earlier 105U
and 905U E-series modules. It provides on-board I/O via a front mounting 20-way
connector and has provision for extra expansion modules (ELPRO 115S or MODBUS
devices) to be connected using a standard RS485 serial connection.
The module can monitor the following types of signals
• Digital (on/off) signals - Contact Closure or Switch
• Analog (continuously variable) signals – Tank level, Motor speed, temperature,
etc
• Pulsed signal - Frequency signal – Metering, accumulated total, rainfall, etc
• Internal Signals – Supply voltage, Supply failure, battery status, etc.
The modules monitor the input signals and transmit the values by radio or Ethernet
cabling to another module or modules that have been configured to receive this
information.
The 915U-2 radio has been designed to meet the requirements of unlicensed operation
for remote monitoring and control of equipment. A radio licence is not required for the
915U-2 in many countries.
Input signals that are connected to the module are transmitted and appear as output
signals on other modules. A transmission occurs whenever a "Change-of-State", "COS"
occurs on an input signal. A "Change-of-State" of a digital or an internal digital input is a
change from "off" to "on" or vice-versa.
For an analog input, internal analog input or pulse input rate a "Change-of-State" is a
configurable value called "Sensitivity". The default Sensitivity is 1000 counts (3%) but
can be changed in the Sensitivity Block page.
In addition to change-of-state messages, update messages are automatically
transmitted on a configurable time basis. This update ensures the integrity of the
system.
Pulse inputs counts are accumulated and the total count is transmitted regularly
according to the configured update time.
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915U-2 Wireless I/O
User Manual