Measurement Computing USB-7204 User Manual page 22

USB-7204 User's Guide
Parameter
Calibration
Input current is a function of applied voltage on the analog input channels. For a given input
Note 1:
voltage, V , the input leakage is approximately equal to (8.181*V
in
Maximum throughput scanning to computer memory is machine dependent. The rates specified are for
Note 2:
Windows XP only.
The AD7870 converter only returns 11-bits (0-2047 codes) in single-ended mode and 12-bits in
Note 3:
differential mode. Firmware versions prior to 2.04 have LSB justified data. Firmware versions from
2.04 on have MSB justified data.
External Gated Sync holds off the first clock pulse after setting up a scan to ensure adequate setup time
Note 4:
for the first conversion.
Range Accuracy (LSB)
±20 V 5.1
±10 V 6.1
±5 V 8.1
±4 V 9.1
±2.5 V 12.1
±2 V 14.1
±1.25 V 20.1
±1 V 24.1
Range Accuracy (LSB)
±10 V 4.0
Table 4. Accuracy components, differential mode - All values are (±)
Range % of Reading
±20 V 0.2
±10 V 0.2
±5 V 0.2
±4 V 0.2
±2.5 V 0.2
±2 V 0.2
±1.25 V 0.2
±1 V 0.2
Table 5. Accuracy components, single-ended mode - All values are (±)
Range % of Reading
±10 V 0.2
Conditions
Table 2. Accuracy, differential mode
Table 3. Accuracy, single-ended mode
Gain Error at full scale (FS)
(millivolts (mV))
40
20
10
8
5
4
2.5
2
Gain Error at FS (mV)
20
22
Specification
Factory Cal factors stored in firmware. Cal factors
must be applied via application software.
–12) µA.
in
Offset (mV)
9.766
9.766
9.766
9.766
9.766
9.766
9.766
9.766
Offset (mV)
19.531
Specifications
Accuracy at FS (mV)
49.766
29.766
19.766
17.766
14.766
13.766
12.266
11.766
Accuracy at FS (mV)
39.531