OM-USB-1208FS User's Guide

Functional Details

USB (based on the application), and the allowed current draw of the PC platform (500 mA for desktop PCs and self-powered hubs, or 100 mA for bus-powered hubs and notebook computers).

With all outputs at their maximum output current, you can calculate the total current requirement of the OM- USB-1208FS USB +5 V as follows:

(OM-USB-1208FS @ 80 mA) + (16 DIO @ 2.5 mA ea) + (2 AO @ 15 mA ea ) = 150 mA

For an application running on a PC or powered hub, the maximum available excess current is 500 mA−150 mA

=350 mA. This number is the total maximum available current at the PC +5 V screw terminals. Measurement Computing highly recommends that you figure in a safety factor of 20% below this maximum current loading for your applications. A conservative, safe user maximum in this case would be in the 350-380 mA range.

Since laptop computers typically allow up to 100 mA, the OM-USB-1208FS in a fully-loaded configuration may be above that allowed by the computer. In this case, you must determine the per-pin loading in the application to ensure that the maximum loading criteria is met. The per-pin loading is calculated by simply dividing the +5 V by the load impedance of the pin in question.

Calibration terminal

The CAL connection (pin 16) is an output you should use only to calibrate the OM-USB-1208FS. Refer to the pinout diagrams on page 13 for the location of this pin. Calibration of the OM-USB-1208FS is software- controlled via InstaCal.

Ground terminals

The four analog ground (AGND) connections provide a common ground for all OM-USB-1208FS input channels. Four ground (GND) connections provide a common ground for the DIO, TRIG_IN, CTR, SYNC and PC +5V connections. Refer to the pinout diagrams on page 13 for the location of the AGND and GND pins.

External trigger terminal

The TRIG_IN connection (pin 18) can be configured for either rising or falling edge. Refer to the pinout diagrams on page 13 for the location of the TRIG_IN terminal pin.

SYNC terminal

The SYNC connection (pin 19) is a bidirectional I/O signal. You can use it for two purposes:

Configure as an external clock input to externally source the A/D conversions. The SYNC terminal supports TTL-level input signals of up to 50 kHz.

Configure as an output to synchronize with a second USB unit and acquire data from 16 channels.

Refer to the pinout diagrams on page 13 for the location of this pin. For more information on synchronizing multiple units, refer to page 21.

Counter terminal

The CTR connection (pin 20) is input to the 32-bit external event. Refer to the pinout diagrams on page 13 for the location of this pin. The internal counter increments when the TTL levels transition from low to high. The counter can count frequencies of up to 1 MHz.

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Omega OM-USB-1208FS Calibration terminal, Ground terminals, External trigger terminal, Sync terminal, Counter terminal
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OM-USB-1208FS specifications

The Omega OM-USB-1208FS is a high-performance data acquisition device designed for engineers and technicians who require accurate data logging and analysis in their experiments and applications. This versatile device is equipped with a range of features that make it an ideal choice for various measurement tasks across different industries.

One of the standout features of the OM-USB-1208FS is its ability to support a wide variety of input signals. The device is equipped with 16 analog input channels, which can be used for both voltage and thermocouple inputs, making it suitable for temperature monitoring and other signal measurements. The analog inputs provide a resolution of 16 bits, ensuring precise and reliable readings. Furthermore, it supports sampling rates of up to 100 kS/s, allowing for rapid data acquisition and real-time monitoring.

In addition to its analog capabilities, the OM-USB-1208FS has digital I/O lines that facilitate control and automation tasks. With 8 digital input/output channels, users can easily manage various external devices, sensors, or actuators, enhancing the overall functionality of the data acquisition system. This makes the device suitable for automation projects, as users can trigger actions based on acquired data.

Another distinguishing feature is the built-in USB interface, which offers a straightforward connection to computers without the need for additional power supplies or complex setups. The device is fully compatible with various operating systems, including Windows, making it easy to integrate into existing systems. The included software allows for easy data logging, visualization, and analysis, simplifying the process for users.

The OM-USB-1208FS is designed with durability and reliability in mind. Its compact and rugged construction ensures that it can withstand the rigors of fieldwork and laboratory use. Moreover, the device's comprehensive range of input types and robust performance specifications make it an asset for researchers across diverse fields, including environmental monitoring, manufacturing, and academic research.

In summary, the Omega OM-USB-1208FS is a powerful data acquisition solution that combines a multitude of features and technologies. With its high-resolution analog inputs, digital I/O capabilities, user-friendly USB interface, and reliable construction, it caters to the diverse needs of professionals seeking to capture and analyze data accurately and efficiently. Whether for academic research, industrial applications, or environmental monitoring, the OM-USB-1208FS stands out as a top choice in the data acquisition landscape.
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