This program simulates the way a process computer works.

The main window of this programme is a picture representing the most

important parts of the process computer: main board and 8 I/O cards.

Each card can be used as:

• analogic input card(AI-124) 24 inputs
• digital input card (DI-124) 24 inputs
• count card- to count impulses (FI-116)- 16 count units
• digital output card (DO-124) (24 outputs)
• analogic output card(AO-106) (6 outputs)

The programme simulates the way each one of this cards works .

For instance: every time an AI-124 card gets some data a light turns on and the

data is displayed. This programme is a variant of a real application that runs on a 386/40 MHz

process computer designed by ICE Felix SA Bucharest. This computer has a QNX 4.2 operating

system and the application's interface is built to "work with" Photon 1.0. The only one

difference between the real application and this programme is the way data is received:

the first one gets data directly from the 8 cards already mentioned and the second

generates data at random.

When initialising the application a 'setup' function is called. This function enables the user to specify

a type for every attached card. The simulator does not provide a setup sequence - the configuration

is static:

• 2 AI cards
• 2 DO cards
• 2 AO cards
• 1 F1 card
• 1 DI card.

Each card is served by a special process (depending on card's type) as it follows(these processes are

launched when setup is completed):

• proc_ai works with the AI-124 card
• proc_di works with the DI-124 card
• proc_fi works with the FI-116 card
• proc_ao works with the AO-106 card
• proc_do works with the DO-124 card

Processes running with the real application communicate with card drivers. For instance proc_di

is blocked waiting for one input to change state. Every time a change of state occurs, the proc_di

process is awakened.

In our case,these processes generate input data at random . Data is sent to the 'usp' process by

means of QNX message passing procedure. Every time 'usp' receives a message, it calls the 'handler'

function that displays data and also turns on a light to specify which card is active.

• The DO-124 marks the state of each output by turning a light on (light on means 1 logical);
• The same works with the DI-124 card for each input.
• The AI-124 displays 4 values (in V) - one value corresponding to a certain input channel.
• One can switch the 4 displayed channels by "clicking" the button related to this card.
• The FI-116 displays the number of impulses received by this card - displayed channels can be
• switched the same way as for the AI-124.

Each one of the AI , DI , FI , DO and AO cards has "on top" a button labelled 'AI_124','DO_124' ,

'AO-124' and so on . When clicking this button a new window is displayed on the screen.This window

shows some more information on data received from the related card:

The AI-124 and DI-124 windows displays 6 graphs - one graph shows data received from one of the 24 input channels.

To switch between graphs you have to click the "NEXT" button.

The DO-124 window displays 24 ON/OFF buttons - each one shows the state of one output.

Clicking the "AUTO" button stops the 'proc_do' from generating data.This way one can control the DO-124

card by means of these 24 buttons (in this case data is sent from 'usp' process to 'proc_do' process) .

The AO-124 has 6 related sliders.Clicking the "AUTO" button one can control the outputs by means of these

sliders (in this case data is sent from 'usp' process to 'proc_ao' process) .