INET-555 Expandable Modular USB Data Acquisition System

Supported Applications

The Omega iNET-400 Series is an expandable modular data acquisition system designed for multi-channel measurement of voltage, current, resistance, thermocouple, RTD, thermistor, strain gage, load cell, potentiometer, accelerometer, and counter/timer signals. The series connects to Windows computers via the iNET-240 USB 2.0 controller, enabling digitization of any combination of channels at an aggregate rate up to 166,000 samples per second.

Applications include laboratory testing and industrial monitoring where universal-input measurement modules connect directly to sensors. The system supports software interfaces including instruNet World Plus (iNET-iWPLUS), LabVIEW drivers (iNET-380 for versions ≥4), DASYLab, Visual Basic, C/C++, and Excel.

Operating Conditions & Performance

The iNET-400 Series operates within an ambient temperature range of 1 to 45°C (34 to 113°F) with humidity below 90% RH. Storage temperatures are rated from -20 to 70°C (-4 to 158°F). The system utilizes a USB 2.0 high-speed connection (480Mbaud) between the computer and iNET-240 controller, extending via DB25 male/female cables in a daisy-chain configuration up to 300 meters with an instruNet terminator at the far end.

Performance specifications vary by card model:

• iNET-430: Features a 16-bit A/D converter. Voltage accuracy for the ±5V range is specified as ±(0.010% + 332.7µV) with 1 ms averaging.
• Thermocouple Accuracy (iNET-430): Type J ranges from 0 to 750°C at ±1°C; Type K ranges from -200 to 1250°C at ±1.2°C.
• RTD Accuracy: For a 1,000 Ω RTD in the range of -100 to 300°C, accuracy is ±0.8°C on iNET-430 (requires OMEGA 10 kΩ shunt resistor iNET-R-10K).
• Thermistor Accuracy: For a 2252 Ω thermistor in the range of 0 to 100°C, accuracy is ±0.47°C on iNET-430 (requires OMEGA 10 kΩ shunt resistor iNET-R-10K).

Each channel supports independently programmable analog filters, integration time, voltage range, and sample rate, plus programmable digital filters (LP, HP, BP, BS). The system requires +5 Vdc and ±12 Vdc power supplied by the iNET-312-8 desktop power supply.

Configuration Options

The series is built around a 4-slot card cage (iNET-400) constructed of solid aluminum, which can be expanded to 8, 12, or 16 slots by bolting cages side-by-side. The iNET-410 interface card must occupy slot #1 in each cage.

Available measurement and I/O cards include:

• iNET-420: Provides 20 single-ended/10 differential voltage inputs (±10V to ±20mV) with a multiplexer, plus 4 digital I/O channels.
• iNET-423: Offers 6 differential voltage inputs with amplifier and filter capabilities; gain is software selectable at 1 or 64. Supports up to six iNET-500 analog low pass Butterworth filter daughter boards (one per channel) with cutoff frequencies of 380 Hz, 1 kHz, 3300 Hz, or 10 kHz.
• iNET-430: Includes a 16-bit A/D converter for voltage inputs (±10V to ±10mV), two precision analog voltage outputs (±10.1V, 14-bit D/A) or two unipolar outputs (0 to 10.1V, 8-bit D/A), and 4 universal digital I/O channels.
• iNET-460: Provides 28 digital I/O channels configured as 12x universal digital I/O (20 mA sink) plus 16x digital I/O (200 mA sink).

The system supports up to four iNET-240 controllers per computer. Accessories include wiring boxes (iNET-510 with screw terminals, iNET-511 with BNC connectors, iNET-512 for strain gages), optical isolators (iNET-330), wall and DIN rail mounting kits (iNET-530), and shunt resistors ranging from 33 Ω to 33 kΩ.

Key Product Differences

The iNET-400 Series is offered in starter system configurations:

• iNET-555: Starter system with USA plug, including the iNET-240 controller, iNET-430 card, iNET-510 wiring box, iNET-400 cage, and power supply.
• iNET-555-EU: Starter system configured for European plugs with identical component contents.

Differences between measurement cards are defined by channel count, input type, and output capabilities. The iNET-420 is optimized for multiplexed voltage inputs without analog outputs, while the iNET-430 provides high-resolution A/D conversion with integrated D/A outputs. The iNET-460 serves exclusively as a digital I/O expansion module.

Thermocouple measurements require an iNET-510 Wiring Box attached to the card cage; thermistor, RTD, resistance, current, and strain gage measurements (1/4 or 1/2 bridge) require external shunt resistors. The iNET-430 A/D card is required for measuring analog voltages when using conditioned signals from iNET-420 or iNET-423 cards routed via the backplane.