DIO

The 825 main board is equipped with four digital input and four digital output ports. DIO option cards may be used for additional I/O options. Option cards contain eight ports which may be used as a combination of inputs and outputs.

Digital I/O

The console command prompt may be used for simple DIO testing.

echo “L000000020000000F” > /dev/mnbd

This sets the state of the mainboard digital outputs. The “L” is the command, the following 8 characters or four hexadecimal bytes represent the state desired. The final 8 characters or four hexadecimal bytes represent a mask of which outputs are to be affected. In this example “F” is used as the mask to set the state of all four on-board outputs.

# echo “I” > /dev/mnbd

This requests the status of the mainboard digital I/O.

# cat < /dev/mnbd

response:

# IA000000000

The last 8 character of the response are hexadecimal digits. Of these the first 4 digits are the state of the digital inputs. The final 4 digits are the state of the outputs. If the input 1 only is active the response is:

# IA000010000

If inputs one and two are active the response is:

# IA000030000

If inputs one, two, three, and four are active the response is:

# IA0000F0000

Only a single hexadecimal digit is needed to represent the state of the four mainboard inputs.

Response	Input 1	Input 2	Input 3	Input 4
0	Off	Off	Off	Off
1	On	Off	Off	Off
2	Off	On	Off	Off
3	On	On	Off	Off
4	Off	Off	On	Off
5	On	Off	On	Off
6	Off	On	On	Off
7	On	On	On	Off
8	Off	Off	Off	On
9	On	Off	Off	On
A	Off	On	Off	On
B	On	On	Off	On
C	Off	Off	On	On
D	On	Off	On	On
E	Off	On	On	On
F	On	On	On	On

For additional structure formats refer to MainboardProtocol

The lib825 library provides functions to facilitate applications performing digital I/O tasks.

To perform these tests with DIO option cards replace /dev/mnbd with /dev/wt1 (for the first DIO option card), /dev/wt2 (for the second installed DIO option card), etc...

The following example shows program code to read and set DIO ports.

Error: Failed to load processor Lineno

No macro or processor named 'Lineno' found

To use this example with a DIO option card replace MNBD_DEV with the number of the installed DIO option card such "1" for the first DIO option card, or "2" for the second installed DIO option card.

If MNBD_REQ_REP_IO_STATUS is used for repeat status on multiple DIO cards or the mainboard and another DIO card at the same time it will be impossible to mnbd_dio_status structure and determine which card is providing the input. However, an array of structures is provided dio_status[x] where x = 0 mainboard, x = 1 first DIO card, x = 2 second DIO card, etc...

For digital I/O event operations refer to the DioEvent class.

DIO Events

About

This document will guide the programmer through the process of creating and using a simple DIO Event using the DioEvent class provided in the standard library (lib825). DIO Events are processed by the mainboard in order to allow a level of redundancy. Should the OPI board kernel crash the mainboard will continue to provide relay functionality and will disable events when their thresholds are reached.

The Code

To use a DIO event follow the example code below.

Error: Failed to load processor Lineno

No macro or processor named 'Lineno' found

The above code would create an event that would enable board 0 (mainboard) pin 0 when the gross weight of scale 1 is less than 250.00 and greater than 0.00.

DIO Counting

Description

Mainboard software 1.15 is required for counting feature. Kernel 2009-10-07 or later is required. All four inputs of the mainboard may be used for counting. The DIO cards allow any one of inputs 1 - 7 to be used for counting. Input 8 may also be used for counting. This allows for up to two inputs per DIO card to be used for counting.

Example

Error: Failed to load processor Lineno

No macro or processor named 'Lineno' found