The figure below shows the GX1034 with its front panel connectors.P2 a 9 pin, D type and P1 a BNC 10MHz output TTL clock. Two additional cPCI connectors (J1 and J2) are used to connect the module to the backplane and to pass in the PCI and interface PXI signals to the board.
GX1034 Board Side View
The GX1034 has an internal 4-wire bus that interfaces to the front through a DB9 connector, providing Hi Sense, Lo Sense, Hi Measure and Lo Measure connections for all on-board standards. In addition, the board has a BNC connector for the 10MHz output clock. The GX1034's standards exhibit excellent long-term stability with absolute accuracy achieved by employing an on-board EEROM, which contains NIST traceable calibration values for source and resistor standards. The module also includes source and measure resources which can be used to support system self-test functions including continuity verification and verification of instrument functionality. Absolute accuracy of the standards is achieved by measuring all standard’ values at the time of manufacture and subsequently saving these values into the module’s EEROM, which can then be accessed by the user when certifying system instrumentation, achieving traceability of the measurement. Features and capabilities of the board are described below.
The 4-wire resistor references include 1W, 10W and 100W resistors' values. The user can select under program control which of those resistors values are connected to the 4–wire output bus.
The 2-wire resistor references include 1W, 10W, 100W, 1WK, 10WK, 100WK, 1WM and 10WM resistor values. The user can program which of those resistors' values are connected at any given time. Connections will be made to the Hi Measure and Lo Measure busses.
The DC source supplies an exceptionally stable +9.0V and -9.0V source and includes a programmable decade resistive divider network for attenuation of the output by factors of 10, 100 and 1000. The DC source output impedance will vary depending on the selected voltage value. The DC source values stored in the on-board EEROM reflect output voltages measured into a 10 GOhm load with an 8.5-digit DMM. The output voltage for each value is available on the Hi Measure and Lo Measure output busses. Approximate output impedance for each attenuator range is presented in the following table. Depending on the application, it may be necessary to compensate for the effects of the voltage source’s output impedance.
Voltage Range |
Approximate Output Impedance |
x 1 |
990 ohms |
x.1 |
900 ohms |
x.01 |
100 ohms |
x.001 |
10 ohms |
AC and DC Source Output Impedance
The AC source supplies a nominal 3.5 VAC (RMS) and employs the decade resistive divider network for attenuation of the output by factors of 10, 100 and 1000. In addition, for each programmable attenuated AC voltage range the user can program the AC frequency to any of the following values: 100Hz, 1KHz, 10KHz, 100KHz, 50Hz, 60Hz and 400Hz. AC source output impedances are similar to those shown in the above table.
The 10 MHz frequency output reference employs a calibrated, high stability oven-controlled crystal oscillator. In addition, a 24-bit divider can be programmed to divide this high precision 10 MHz frequency reference clock. The 10 MHz high stability oven-controlled crystal oscillator can provide the 10MHz PXI bakplane clock source when installed in the star-controller slot.
The card has an on board programmable current source. Output current can be programmed to any value between 0-19.9mA with 16-bit resolution. The current source’s voltage compliance range is 0 to +12.5 volts.
The card also has the capability to measure differential voltages on the 9-pin connecter using a 16-bit ADC with voltage range of –10V to +10V.
The card also has the capability to measure resistance using the combination of the on-board current source and the capability to measure differential voltages of –10V to +10V on the 9-pin connecter.
The board has an on-board temperature sensor that is been used to record the temperature at calibration time. This value is then saved on the on-board non-volatile memory. The driver then uses the recorded temperature to correct for temperature variations.
Using its internal components, the card can execute a built-in-test (BIT) by connecting a special connector available from by Marvin Test Solutions.