Measurement Computing USB-2020 - Manual (Page 9)

USB-2020 User's Guide Installing the USB-2020
Removing USB-2020 boards from Windows XP systems
Device Manager may require up to 30 seconds to detect the removal of a USB-2020 board from a Windows XP
system with Service Pack 2 installed. This time increases with each additional connected device. If you remove
four devices from your system, the time required for Device Manager to update may be almost two minutes.
If you re-attach the USB-2020 to your system before Device Manager updates, the bottom LED does not turn
on. Your system does not detect new hardware until Device Manager first detects that hardware has been
removed. The InstaCal software is unresponsive during this re-detection time. Wait until Device Manager
updates with the new hardware before running InstaCal. The USB-2020 is detected by the system when the top
(Device Ready) LED is on.
Calibrating the hardware
The Measurement Computing Manufacturing Test department performs the initial factory calibration. The
calibration coefficients are stored in non-volatile RAM.
You can use InstaCal to recalibrate the USB-2020. No external equipment or user adjustments are required.
At run time, the calibration factors are loaded into system memory and are automatically retrieved each time a
different ADC range is specified. A full calibration typically takes less than two minutes.
Before you calibrate the device, turn your computer on and allow at least 30 minutes for the surrounding
temperature to stabilize. For best results, calibrate the device immediately before making critical measurements.
The high resolution analog components on the board are sensitive to temperature. Pre-measurement calibration
insures that your device is operating with optimum calibration values.
Connecting the board for I/O operations
Connectors, cables, and accessory products
The following table lists the board connectors, applicable cables, and compatible accessory products for the
USB-2020.
Board connectors, cables, and compatible hardware
Parameter Specification
Connector types

Four standard BNC female connectors for analog input,
clock I/O, and digital trigger input

40-pin IDC connector
Compatible cable for the BNC connectors Standard BNC cable
Compatible cables C40FF-x: 40-conductor ribbon cable, female both ends, x = length
in feet.
C40-37F-x: 40-pin IDC to 37-pin female D connector, x = length in
feet.
Compatible accessory products
(using the C40FF-x cable)
CIO-MINI40
Compatible accessory products
(using the C40-37F-x cable)
CIO-MINI37
SCB-37
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