OMB-AI-EXP32 User's Guide
Specifications
13
Analog input DC voltage measurement accuracy
The OMB-AI-EXP32 is a multiplexer-based channel expansion module that increases the number of voltage
input channels of a OMB-DAQ-2416 series host module. For voltage accuracy information, refer to the
electrical specification of the OMB-DAQ-2416 host device that is the interface to the OMB-AI-EXP32
interface.
Digital input/output
Table 5. Digital input specifications
Number of I/O
16 channels
Configuration
Each DIO bit can be independently read from (DIN) or written to (DOUT).
The DIN bits can be read at any time whether the DOUT is active or tri-stated.
Input voltage range
0 to +15 V
Input type
CMOS (Schmitt trigger)
Input characteristics
47 kΩ pull-up/pull-down resistor, 28 kΩ series resistor
Maximum input voltage range
0 to +20 V maximum (power on/off, relative to DGND pins 29,30,61,62)
Pull-up/pull-down configuration
All pins pulled up to +5 V via individual 47 kΩ resistors.
The JP1 (DIO 8- 15) shorting block default position is pull-up or "HI."
The JP2 (DIO 16- 23) shorting block default position is pull-up or "HI."
Pull down capability is available by placing either of the JP1 and JP2 shorting
blocks in the "LO" position.
Transfer rate (software paced)
500 port reads or single-bit reads per second, typical.
Input high voltage
1.3 V minimum, 2.2 V maximum
Input low voltage
1.5 V maximum, 0.6 V minimum
Schmitt trigger hysteresis
0.4 V minimum, 1.2 V maximum
Note 1:
DGND pins (pins 29, 30, 61, 62) are recommended for use with digital input and digital output pins.
The DGND and GND pins are common and are isolated from earth ground.
Table 6. Digital output specifications
Number of I/O
16 channels
Configuration
Each DIO bit can be independently read from (DIN) or written to (DOUT).
The DIN bits may be read at any time whether the DOUT is active or tri-stated
Output characteristics
47 kΩ pull-up, open drain (DMOS transistor)
Pull-up configuration
All pins pulled up to +5 V via individual 47 kΩ resistors.
The JP1 (DIO 8- 15) shorting block default position is pull-up or "HI."
The JP2 (DIO 16- 23) shorting block default position is pull-up or "HI."
Transfer rate (software paced)
Digital output – 500 port writes or single-bit writes per second typical.
Output voltage range
0 to +5 V (no external pull up resistor, internal 47 kΩ pull-up resistors
connected to +5 V by default)
0 to +15 V maximum (Note 4)
Drain to source breakdown voltage
+50 V minimum
Off state leakage current (Note 5)
0.1 µA
Sink current capability
150 mA maximum (continuous) per output pin
150 mA maximum (continuous) for all eight channels
DMOS transistor on-resistance
(drain to source)
4 Ω
Note 2:
Each DMOS transistor’s source pin is internally connected to GND.
Note 3:
DGND pins (pins 29, 30, 61, 62) are recommended for use with digital input and digital output pins.
The DGND and GND pins are common and are isolated from earth ground.
Note 4:
The external pull-up is connected to the digital output bit through an external pull-up resistor. Adding
an external pull-up resistor connects it in parallel with the internal 47k Ω pull-up resistor of that
particular digital input/output bit. Careful consideration should be made when considering the external
pull-up resistor value and the resultant pull-up voltage produced at the load.
