Strip Chart ► Hardware ► Standard ► Specifications
The following are the specifications for the Connectors to the USB DAQ device. To setup the logic for these terminals see Standard USB Preferences.
Analog Input
Channels AI0-AI1, AI2-AI3, AI4-AI5, AI6-AI7 are differential voltage input connectors to a 12 bit A/D converter. They have a dynamic range of -10 to 10 volts. That means that the voltage resolution is 0.004882 volts (4.882 millivolts). If a gain is set then it is applied before digitization. If the gain is 20 then the dynamic range is 0.5 volts and the resolution is 0.2441 millivolts. So, for low amplitude signals the gain setting can increase the effective resolution.
Analog Output
Channels AO0 and AO1 are output voltage terminals. Their D/A converters are 10 bits and output in the range from 0 to 5 Volts. The values for them are set to the input parameters in the USB Preferences window.
Digital Output
Channels IO0, IO1, IO2, IO3 are digital output voltage terminals. When a digital channel is set on it has the value of 5 volts, when off it has a value of 0 volts. Access to 16 other digital output channels are through the DB25 connector. You need a optional board to access those pins.
Power
Terminals marked as +5V are power output connectors. They are powered through the computer's USB bus so do not try to draw any more power than that rated for your computer, or powered hub if the USB device is connected to a powered hub. For many computers and powered hubs the maximum power that can be drawn is 450mA. If you need additional power then use a external power supply like from a transformer.
Ground
Terminals marked as GND are grounds on a common ground-bus. The ground is connected to your computer's ground so it may or may not be well isolated. Since it is a common ground there is no isolation between ground terminals, a fact that can lead to cross talk between sensors connected to the grounds.