Measurement Computing USB-1608GX-2AO - Manual (Page 19)

USB-1608GX-2AO User's Guide Specifications
19
Analog input/output calibration
Table 9. Analog I/O calibration specifications
Parameter Specification
Recommended warm-up time 15 minutes min
Calibration method Self-calibration (firmware)
Calibration interval 1 year (factory calibration)
AI calibration reference +5 V, ±2.5 mV max. Actual measured values stored in EEPROM.
Tempco: 5 ppm/°C max
Long term stability: 15 ppm/1000 hours
AO calibration procedure The analog output pins are internally routed to the analog input circuit.
For best calibration results, disconnect any AOUTx connections at the terminal block
pins prior to performing AOUT calibration.
Digital input/output
Table 10. Digital I/O specifications
Parameter Specification
Digital type CMOS
Number of I/O 8
Configuration Each bit may be configured as input (power on default) or output
Pull-up configuration The port has 47 kΩ resistors configurable as pull-ups or pull-downs (default) via
internal jumper (W1).
Digital I/O transfer rate
(system-paced) 33 to 8000 port reads/writes or single bit reads/writes per second typ,
system dependent.
Input high voltage 2.0 V min
5.5 V absolute max
Input low voltage 0.8 V max
–0.5 V absolute min
0 V recommended min
Output high voltage 4.4 V min (IOH = –50 µA)
3.76 V min (IOH = –2.5 mA)
Output low voltage 0.1 V max (IOL = 50 µA)
0.44 V max (IOL = 2.5 mA)
Output current ±2.5 mA max
External trigger
Table 11. External trigger specifications
Parameter Specification
Trigger source TRIG input
Trigger mode Software programmable for edge or level sensitive, rising or falling edge, high or low
level. Power on default is edge sensitive, rising edge.
Trigger latency 1 µs + 1 clock cycle max
Trigger pulse width 100 ns min
Input type Schmitt trigger, 33 Ω series resistor and 49.9 kΩ pull-down to ground
Schmitt trigger hysteresis 0.4 V to 1.2 V
Input high voltage 2.2 V min
5.5 V absolute max
Input low voltage 1.5 V max
–0.5 V absolute min
0 V recommended min