ProSoft Technology MVI56E-LDM - Manual (Page 56)

Understanding the MVI56-LDM API ControlLogix Platform ♦ "C" Programmable
Developer's Manual Linux Application Development Module
Page 50 of 264 ProSoft Technology, Inc.
March 12, 2014
4.13 Led_Sample
The LED Sample program is designed to show one or more groups of
functionality provided in the module. This sample covers the following functions:

Open backplane driver
 Interpreting errors returned by the backplane driver
 Reading module configuration jumpers
 Display message on the 4-character front panel
 Changing the state of the front panel LEDs
This sample program illustrates how to interact with the MVI56E-LDM hardware
at the most basic level.
To use this program, establish a command window using telnet or similar
terminal software on the PC using either the Ethernet or Serial P1 port.
Login as user: root, using password password.
To execute the sample...
From the default home directory (
/psft
), type the command
./Led_Sample&
. This
will run the LED Sample program in the background.
While looking at the sample source, you'll see that the main program will....

open a connection to the hardware via the OCX library API
OCXcip_Open
.
Although the
OCXcip_OpenNB
routine could be used, (since this sample does
not communicate across the backplane), the module status will not flash
red/green if opened with the NB variant.
 display "
open success
" on the 4-character display using the function Display.
 read the state of the Setup Jumper using the function
ReadSwitches
and prints
this information to the console.
 read the state of the serial configuration jumpers using
Get_Serial_Config
and prints this information to the console.
 initialize timer functionality
 Change LEDs on the front panel to a default state using the
SetLed
function:
o Module status if the OK LED.
o
User LED is the APP LED.
o
LED3 is the ERR LED.
The program then goes into an infinite loop, looking for the expiration of two
timers:

a fast timer which cycles the LEDs through their states and scrolls the last
string across the 4-character front panel display.
 a slow timer which updates the string for the front panel display.