MicroBrick I/O - Industrial Control Links

Universal Input ModulesMicroBrick Distributed I/O ModulesThe MicroBrick Universal Input modules accept signals from analog sensors thatmonitor levels, flows, temperatures, pressures, etc. as well as discrete contact closures.The Universal Input Modules are unique in that they include the signal conditioningcircuits required for direct support of thermocouples, RTDs and thermistortemperature sensors, millivolt type sensors such as strain gages, as well asconventional 5V and 20mA devices. The inputs can also be used with discrete contactclosures. Built-in signal conditioning eliminates the need for most external signalconverters. With the addition of two external resistors, an input channel can accepthigh-level bipolar voltage inputs such as +/-5Vdc and +/-10Vdc. Measurements aremade with high-accuracy 24-bit Analog-to-Digital (A/D) converters. There are twoversions of Universal Input Modules: the UI8I and the UI12.The UI8I input module has a total of 8 dual analog inputs; one “voltage” input and one“resistance” input. When a channel is configured to support a 3-wire RTD temperaturesensor, both inputs are used together to accurately measure the sensor resistance,and therefore the temperature, while compensating for the resistance of the wires tothe sensor head. For all other sensors that are 2-wire devices, the channels inputsmay be configured separately, yielding a total of 16 analog inputs, 8 for voltage typesensors (5Vdc, 20mA, mV, and thermocouples) and 8 for resistance type sensors(thermistors, 1000 ohm 2-wire RTDs and potentiometers). Each pair of inputs isisolated from each of the other input channels as well as the MicroBricksmicroprocessor and communications circuits. Internal DC-DC converters are providedwithin the Universal Input module, so no external isolated power is required.The UI12 input module does not support three wire RTDs but does support the rest ofthe sensor styles with a total of 12 inputs supporting all other sensor types. The UI12has two “sides” that are isolated from communications and power, from side to side,but not between channels 1 through 6 or channels 7 through 12.Input mode ConfigurationThe MicroBrick Universal inputs may be individually configured to accept processcontrol signals and temperature sensors through the built-in operator interface, or bycommands from any Modbus (or BrickNet) Master, or using the ICL ScadaFlex I/OToolbox software.The configuration of a MicroBrick Universal Input module can be read or changed atany time with simple register commands. The module configuration is retained innonvolatile EEROM memory so that the settings are “remembered” even after themodule is powered off. No batteries are used.For current loop sensors, the user must also set switches next to the input terminalblocks that enable or disable precision current sense resistors required for handling20mA sensors.RAW ModeRaw mode bypasses all scaling and calibration in the UIO module, providing “raw” 16-bit (truncated 24-bit) readings from the A/D converter. A full scale reading of 65535Copyright © 2007 Industrial Control Links, Inc. All Right Reserved49