Programming The Dio-16.Pci - SeaLevel DIO-16.PCI User Manual

Programming the DIO-16.PCI

Sealevel's SeaI/O software is provided to assist in the development of reliable applications for the Sealevel
Systems family of digital I/O adapters. Included in Sealevel's software and drivers are driver functions for
use in accessing the I/O as well as helpful samples and utilities.
Programming for Windows
The SeaI/O API (Application Programmer Interface) provides a variety of useful high-level function calls
implemented in a Windows dynamic link library (DLL). The API is defined in the help file
(Start/Programs/SeaIO/SeaIO Help) under "Application Programmers Interface". This help file also
includes detailed information dealing with installation / removal of the software and information about
latency, logic states, and device configuration.
For C language programmers we recommend using the API to access the DIO-16.PCI. If you are
programming in Visual Basic, using the ActiveX control included with SeaI/O is advised.
Samples and Utilities
A variety of sample programs and utilities (both executable and source code) are included in the software
for the SeaI/O. Further documentation on these samples can be found by selecting
"Start/Programs/SeaIO/Sample Application Description." If you have any problems locating these files,
please contact Sealevel's Technical Support at 864-843-4343 or email support@sealevel.com.
Programming for Linux
SeaI/O for Linux consists of two major parts: a kernel module and a library. The kernel module is a simple
IO pass-through device, allowing the library to handle the more sophisticated functions provided to SeaI/O
users. It is provided in a 'tarball' format and can easily be compiled and included in the kernel build.
Digital I/O Interface
The DIO-16.PCI provides two parallel input/output (I/O) ports. The ports are organized as ports A, B, C, and
D. Port A is an input port interfaced to optically isolated inputs, while port C is the reed relay output port.
Input Port
Port A is an eight bit input port connected to optically isolated input sensors. Each sensor can be used to
interface a voltage input and then sense whether the voltage is on or off. Each sensor is isolated (with
respect to a common ground) from every other sensor, and also isolated with respect to the host PC ground.
This means that signals such as low-level AC line voltage, motor servo voltage, and control relay signals
can be 'sensed', or read by the PC, without the risk of damage due to ground loops or ground faults.
Each sensor input pair has a current limiting resistor that is used to limit the input current to the opto-
isolator. The opto-isolator has two 'back-to-back' diodes internally. This allows AC or DC signals to be
sensed, regardless of polarity. When the applied voltage is high enough to cause the led in the opto-isolator
to turn-on, the output of the opto-isolator goes low (0 volts), and the signal is read as a low logic level (binary
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© Sealevel Systems, Inc. 8002 Manual | SL9021 10/2022