OMEGA OMB-DAQ-2416-4AO (01) PDF Document

The OMEGA OMB-DAQ-2416-4AO is a multifunction measurement and control board designed for the USB bus. Its key features include:

Analog Inputs: A full-speed, multiplexed 24-bit measurement system providing up to 16 differential and up to 32 single-ended (SE) analog inputs. It offers software-selectable input ranges from ±0.078 V to ±20 V.

Input Isolation: Provides a minimum of 500 VDC input isolation between field wiring and the USB interface to protect your computer.

Thermocouple Inputs: Up to 16 analog inputs can be configured as differential thermocouple (TC) inputs, with built-in cold-junction compensation and open thermocouple detection.

Expandability: You can add up to 32 single-ended or 16 differential channels by connecting an OMB-AI-EXP32 expansion module.

Analog Outputs: Four 16-bit analog output channels with an update rate of up to 1102 S/s and an output range of ±10 V.

Digital I/O and Counters: The device has eight high-speed digital I/O lines and two 32-bit counters. DIO channels can be expanded up to 24 by connecting an OMB-AI-EXP32 expansion module.

Connectivity: Six banks of removable screw-terminal blocks provide connectivity for analog inputs, digital I/O, counter/timer channels, and analog outputs.

When you unpack your OMEGA OMB-DAQ-2416-4AO, you should verify that the following components are included:

Hardware:

• OMEGA OMB-DAQ-2416-4AO module

• USB cable (2-meter length)

• OMB-DAQ-2416-ADAP (+5VDC, 10 Watt regulated power supply)

As with any electronic device, you should take care while handling the OMEGA OMB-DAQ-2416-4AO to avoid damage from static electricity. Before removing the device from its packaging, ground yourself using a wrist strap or by simply touching the computer chassis or another grounded object to eliminate any stored static charge.

To connect the OMEGA OMB-DAQ-2416-4AO to your system, turn your computer on, and then follow these steps:

1. Connect the OMB-DAQ-2416-ADAP power supply to the device’s external power connector, and plug the other end into a power outlet.

2. Connect the USB cable to the device’s USB connector and to a USB port on your computer. A USB 2.0 port is recommended.

When you connect the device for the first time, a “Found New Hardware” message will open as it is detected. When the message closes, the installation is complete. The power LED will blink during initialization and then remain solid if properly detected.

Caution: Do not disconnect any device from the USB bus while the computer is communicating with the OMEGA OMB-DAQ-2416-4AO, or you may lose data and/or your ability to communicate with the device.

Use the 37-pin expansion connector to connect the OMEGA OMB-DAQ-2416-4AO to an OMB-AI-EXP32 expansion module. To connect the two devices directly to each other, follow these steps:

1. Disconnect the USB cable from the OMEGA OMB-DAQ-2416-4AO.

2. Remove the external power cable from the OMEGA OMB-DAQ-2416-4AO.

3. Connect the two devices together by inserting the OMB-AI-EXP32’s DSUB37 connector into the DSUB37 connector on the OMEGA OMB-DAQ-2416-4AO.

4. Turn the connected modules over and secure the connection by screwing the connection plate to both modules.

5. Connect the external power supply to the OMEGA OMB-DAQ-2416-4AO’s external power connector, and plug the other end into an AC outlet.

6. Connect the USB cable from the OMEGA OMB-DAQ-2416-4AO to the host computer’s USB port.

Connect to a USB 2.0 high-speed hub to achieve the highest transfer rate (480 Mbps). When connected to a USB 1.1 full-speed port, the transfer rate is limited to 12 Mbps.

Caution: Turn off power to all devices connected to the system before making connections. Electrical shock or damage to equipment can result even under low-voltage conditions.

Caution: Always handle components carefully, and never touch connector terminals or circuit components unless you are following ESD guidelines in an appropriate ESD-controlled area. These guidelines include using properly-grounded mats and wrist straps, ESD bags and cartons, and related procedures.

Avoid touching board surfaces and onboard components. Only handle boards by their edges. Make sure the OMEGA OMB-DAQ-2416-4AO does not come into contact with foreign elements such as oils, water, and industrial particulate.

The discharge of static electricity can damage some electronic components. Semiconductor devices are especially susceptible to ESD damage.

Follow these guidelines for differential connections:

• When connecting differential voltage inputs to a “floating” voltage source, ensure there is a DC return path from each voltage input to ground. You can create this path by connecting a resistor of approximately 100 kΩ from each input to a GND pin (pins 18, 36, 39, 42, 44, 46, 66, 81, 84).

• Leave any unused input channels either floating or tied to GND pins.

• Keep source impedances as small as possible to avoid settling time and accuracy errors.

• When configuring thermocouple sensors, keep any stray capacitance as small as possible relative to GND to avoid settling time and accuracy errors. For thermocouple channels, do not provide an external return path to ground, as this is done internally.

When the OMEGA OMB-DAQ-2416-4AO is connected to a computer, in its normal idle state both LEDs are lit solid green.

Power LED (Top LED):

• The Power LED blinks when you plug in the power supply and continues to blink while the device initializes. If it continues blinking for more than ½ second, there is a problem with the device and you should cycle the power.

• If an application issues a “blink LED” command, the Power LED will blink a few times.

Activity LED (Bottom LED):

• The Activity LED blinks rapidly when both the USB and external power cables are plugged in. It continues blinking rapidly while connecting to the computer, and then turns solid.

• Whenever the device receives a USB command, the Activity LED blinks off and then returns to solid green.

• When an analog in or analog out scan is running, the Activity LED blinks continuously.

You can make up to 16 high-resolution differential thermocouple measurements with the OMEGA OMB-DAQ-2416-4AO. Built-in cold-junction sensors are provided for each of the screw-terminal blocks.

• Do not connect thermocouples as single-ended, as this can cause false readings.

• You do not need to use ground-referencing resistors because the analog front-end circuit level-shifts the thermocouple’s output into the common-mode input range of the A/D.

• When configuring thermocouple sensors, keep any stray capacitance as small as possible relative to GND (pins 18, 36, 39, 42, 44, 46, 66, 81, 84) to avoid settling time and accuracy errors.

The device provides open thermocouple detection (OTD), electrostatic discharge (ESD) protection, and cold junction compensation (CJC) for accurate temperature readings.

Each of the eight DIO bits has a 47 kΩ pull-up/pull-down resistor. By default, all pins are pulled up to +5V. To configure these bits for the 0V pull-down option, you need to open the case and access the three-pin jumper labeled JP1.

1. Turn over the OMEGA OMB-DAQ-2416-4AO and rest it on its top on a flat, stable surface.

2. Remove the five screws from the bottom of the module.

3. Holding both the top and bottom sections of the module, turn it back over, rest it on the surface, and carefully remove the top portion of the case.

4. To pull the digital pins down to ground (0V), place the shorting block across pins 2 and 3 of JP1. To pull the digital pins up to +5V (default), place the shorting block across pins 1 and 2.

You can place an external pull-up resistor on any of the DIO bits, which allows you to pull the DIO bit up to a voltage that exceeds the internal +5 V pull-up voltage.

When using external pull-up resistors, be aware of the following:

• You should either remove the internal JP1 jumper, or store it by attaching it to only one of the three pins.

• When using external pull-up resistors, the internal resistors cause slight impedance shifts to digital lines in the “on” state as the number of lines in the “off” state changes.

The OMEGA OMB-DAQ-2416-4AO is initially calibrated using an NIST-traceable method. A correction factor for each AIN and AOUT range is stored in non-volatile memory. Allow a 45-minute warm-up period before performing any calibration.

Factory Calibration

You can return the device for a new factory calibration and certificate.

Self Calibration

Use the InstaCal software to calibrate the device whenever the ambient temperature changes by more than ±10 °C from the last self-calibration.

• This procedure can be performed with thermocouple and voltage inputs connected to the input terminal blocks.

• To calibrate the AOUT circuits, disconnect the analog outputs at the terminal block pins to ensure optimum calibration results.

Power Specifications

Environmental Specifications