Measurement Computing USB-QUAD08 - Manual (Page 30)

USB-QUAD08 User's Guide Specifications
30
Digital I/O
– Timer outputs – Terminal count outputs
Table 3. Output specifications
Parameter Specification
Number of I/O 8 independent
Configurable Timer outputs (DIO6, DIO7 only), Terminal count/Modulo, Input/Output (default)
Input:
Input characteristics Weak 10 kΩ resistor pulled-up to 5V with protection diode (+V
USB
– diode drop).
Input high +2.0 V to 42.4 V
pk
50 VDC
Input low 0 V to 0.8 V
Output:
Output characteristics Open-collector Darlington transistors with CEMF suppression diodes (ULN2803)
Output logic supply User voltage supply up to 50 VDC (42.4 V
pk
) for strong drive.
CEMF Supply (CLMP+) Connect to logic supply positive terminal up to 50 VDC (42.4 V
pk
)
Output high 2.0 VDC to 50 VDC (42.4 V
pk
); dependent upon logic supply.
Output low <0.8 V
Output sink current 500 mA per pin, 2.5 A max. per device (parallel connections for higher current needs)
requires external supply.
Output generation Counter events or timer outputs (bits 6 and 7); asynchronous generation
Asynchronous throughput 4000 updates/second, typ (tested on Windows XP and Windows Vista32)
Timer outputs:
Number of channels Two 16-bit
 Timer Output 0 (DIO6)
 Timer Output 1 (DIO7)
Effective frequency range 0.01123 Hz to 5 MHz
Trigger and pacer
Table 4. Trigger and pacer specifications
Parameter Specification
Digital type Edge/level sensitive; software-selectable.
Trigger types Start acquisition process
Pacer Latch counter values for read back
Trigger and pacer inputs
 Internal (software)
 External
Trigger and pacer input –0.5 V to 7.0 V
External pacer frequency 8 MHz, max
Indicator LEDs
Table 5. LED specifications
Parameter Specification
Power LED Indicates that the device’s microcontroller has power and is running.
Status LED Indicates that the USB is configured; blinks to indicate USB traffic.
Channel LEDs Indicates that the encoder/counter is receiving a valid signal on any of the inputs.