Omega OM-USB-1208FS manual Analog output terminals D/A OUT 0 and D/A OUT, Power terminals

Models: OM-USB-1208FS

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OM-USB-1208FS User's Guide

Functional Details

For more information on analog signal connections

For more information on single-ended and differential inputs, refer to the the OMB-DAQ-2416 Series and OM- USB Series General Guide to Signal Connections (available on our web site at www.omega.com/manuals/manualpdf/M4830.pdf).

Analog output terminals (D/A OUT 0 and D/A OUT 1)

You can connect up to two analog output connections to the screw terminal pins 13 and 14 (D/A OUT 0 and D/A OUT 1). Refer to the pinout diagrams on page 13 for the location of these pins.

Each channel can be paced individually at rates up to 10,000 updates per second. Both channels can be paced simultaneously using the same time base at 5000 updates per channel. The 0-4.096 V output range provides a convenient 1 mV per LSB when setting the output voltage levels.

Digital I/O terminals (Port A0 to A7, and Port B0 to B7)

You can connect up to 16 digital I/O lines to the screw terminal containing pins 21 to 40 (Port A0 to Port A7, and Port B0 to Port B7.) Refer to the pinout diagrams on page 13 for the location of these pins. You can configure each digital port for either input or output.

When you configure the digital bits for input, you can use the digital I/O terminals to detect the state of any TTL level input. Refer to the schematic shown in Figure 8. If the switch is set to the +5 V input, Port A0 reads TRUE (1). If you move the switch to GND, Port A0 reads FALSE.

Figure 8. Schematic showing switch detection by digital channel Port A0

For more information on digital signal connections

For more information on digital signal connections and digital I/O techniques, refer to the OMB-DAQ-2416 Series and OM-USB Series General Guide to Signal Connections (available on our web site at www.omega.com/manuals/manualpdf/M4830.pdf).

Power terminals

The PC +5V connection (pin 30) is on the bottom screw terminal of the OM-USB-1208FS. Refer to the pinout diagrams on page 13 for the location of this pin. This terminal draws power from the USB connector. The +5 V screw terminal is a 5 volt output that is supplied by the host computer.

Caution! The +5 V terminal is an output. Do not connect to an external power supply or you may damage the OM-USB-1208FS and possibly the computer.

The maximum total output current that can be drawn from all OM-USB-1208FS connections (power, analog and digital outputs) is 420 mA. This maximum applies to most personal computers and self-powered USB hubs. Bus-powered hubs and notebook computers may limit the maximum available output current to 100 mA.

Just connecting the OM-USB-1208FS to your computer draws 80 mA of current from the USB +5 V supply. Once you start running applications with the OM-USB-1208FS, each DIO bit can draw up to 2.5 mA, and each analog output can draw 15 mA. The maximum amount of +5 V current available for experimental use, over and above that required by the OM-USB-1208FS, is the difference between the total current requirement of the

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Omega OM-USB-1208FS Analog output terminals D/A OUT 0 and D/A OUT, Digital I/O terminals Port A0 to A7, and Port B0 to B7