1. Description
1.1. Ada for Automation
Ada for Automation (A4A in short) is a framework for designing industrial automation applications using the Ada language.
It makes use of the libmodbus library to allow building a ModbusTCP client or server, or a Modbus RTU master or slave.
It can also use Hilscher communication boards allowing to communicate on field buses like AS-Interface, CANopen, CC-Link, DeviceNet, PROFIBUS, EtherCAT, Ethernet/IP, Modbus TCP, PROFINET, Sercos III, POWERLINK, or VARAN.
With the help of GtkAda, the binding to the Graphic Tool Kit, one can design Graphical User Interfaces.
Thanks to Gnoga, built on top of Simple Components, it is also possible to provide a Web User Interface.
Nice addition is the binding to the Snap7 library which allows to communicate with SIEMENS S7 PLCs using S7 Communication protocol ISO on TCP (RFC1006).
Of course, all the Ada ecosystem is available.
Using Ada bindings, C, C++, Fortran libraries can also be used.
And, since it is Ada, it can be compiled using the same code base to target all major platforms.
1.2. This demo application
This is a demo application featuring:
-
a basic command line interface,
-
a basic web user interface making use of Gnoga,
-
a kernel with a Modbus TCP Server and Modbus TCP IO Scanning (K1),
-
a trivial application that plays with 16 push buttons and 16 LEDs.
This application is meant to play with 010 a4a_piano.
It shares most of the source code of "020 a4a-k1-cli".
2. Projects diagram
The following picture shows the diagram of projects :

3. License
Those files are included in the Ada for Automation root folder :
COPYING3
The GPL License you should read carefully.
GNU GENERAL PUBLIC LICENSE Version 3, 29 June 2007
COPYING.RUNTIME
GCC RUNTIME LIBRARY EXCEPTION Version 3.1, 31 March 2009
Hence, each source file contains the following header :
------------------------------------------------------------------------------
-- Ada for Automation --
-- --
-- Copyright (C) 2012-2023, Stephane LOS --
-- --
-- This library is free software; you can redistribute it and/or modify it --
-- under terms of the GNU General Public License as published by the Free --
-- Software Foundation; either version 3, or (at your option) any later --
-- version. This library is distributed in the hope that it will be useful, --
-- but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHAN- --
-- TABILITY or FITNESS FOR A PARTICULAR PURPOSE. --
-- --
-- As a special exception under Section 7 of GPL version 3, you are granted --
-- additional permissions described in the GCC Runtime Library Exception, --
-- version 3.1, as published by the Free Software Foundation. --
-- --
-- You should have received a copy of the GNU General Public License and --
-- a copy of the GCC Runtime Library Exception along with this program; --
-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
-- <http://www.gnu.org/licenses/>. --
-- --
------------------------------------------------------------------------------
4. Building
The provided makefile uses GPRbuild and provides six targets:
-
all : builds the executable,
-
app_doc : creates the documentation of the source code,
-
clean : cleans the space.
Additionally one can generate some documentation using Asciidoctor with :
-
read_me_html : generates the README in HTML format,
-
read_me_pdf : generates the README in PDF format,
-
read_me : generates the README in both formats.
5. Running
This application is meant to play with 010 a4a_piano.
Of course, it can also play with a physical device of your own.
In a console:
Build the application:
make
Optionally create the documentation:
make app_doc
Run the application:
make run
Use Ctrl+C to exit.
Optionally clean all:
make clean
6. Directories
bin
Where you will find the executable.
doc
The place where GNATdoc would create the documentation.
obj
Build artifacts go here.
src
Application source files.
7. Application
This is a basic Ada for Automation application which implements Modbus TCP IO Scanning and plays with 16 push buttons and 16 LEDs.
It has a Command Line and Web User Interfaces and sends Modbus TCP requests to the server reading Input bits and writing Coils.
Modbus TCP Server is not used at the moment.
7.1. Deployment diagram

7.2. Activity diagram
The Kernel manages the communication channels and provides an interface to those, namely the packages "A4A.Memory.MBTCP_IOScan" and "A4A.Memory.MBTCP_IOSlave".



7.3. Modbus TCP IO Scanning Configuration
For each Modbus TCP Server define one client configuration task and declare all clients configurations in the array
package A4A.Application.MBTCP_Clients_Config is
--------------------------------------------------------------------
-- Modbus TCP Clients configuration
--------------------------------------------------------------------
-- For each Modbus TCP Server define one client configuration task
Config1 : aliased Client_Configuration :=
(Command_Number => 2, -- (3)
Enabled => True,
Debug_On => False,
Task_Period_MS => 10,
Retries => 3,
Timeout => 0.2,
-- Using an IP Address
-- Node => To_Bounded_String ("127.0.0.1"), -- (1)
-- or a Node name, i.e. example.com
-- Node => To_Bounded_String ("localhost"), -- (1)
-- This one for the Docker demo
Node => To_Bounded_String ("a4a_piano"), -- (1)
Service => To_Bounded_String ("1504"), -- (2)
-- Standard : 502
Commands => -- (4)
(
-- Period Offset Offset
-- Action Enabled Multiple Shift Number Remote Local
1 =>
(Read_Input_Bits, True, 10, 0, 16, 0, 0),
2 =>
(Write_Bits, True, 10, 5, 16, 0, 0)
)
);
Config2 : aliased Client_Configuration :=
(Command_Number => 2,
Enabled => True,
Debug_On => False,
Task_Period_MS => 100,
Retries => 3,
Timeout => 0.2,
Node => To_Bounded_String ("127.0.0.1"),
Service => To_Bounded_String ("1503"), -- My own MBTCP server
Commands =>
(
-- Period Offset Offset
-- Action Enabled Multiple Shift Number Remote Local
1 =>
(Read_Registers, True, 10, 0, 10, 0, 0),
2 =>
(Write_Registers, True, 30, 1, 10, 0, 0)
)
);
-- Declare all clients configurations in the array
-- The kernel will create those clients accordingly
MBTCP_Clients_Configuration : Client_Configuration_Access_Array :=
(1 => Config1'Access, -- (5)
2 => Config2'Access);
end A4A.Application.MBTCP_Clients_Config;
1 | Modbus TCP Server IP Address : 127.0.0.1 (localhost) |
2 | Modbus TCP Server port : 1504 (A4A_Piano) |
3 | Commands number : 2 (since we declare two commands in the array) |
4 | Commands array : one read and one write commands |
5 | Configurations array : add our configuration |
7.4. Modbus TCP Server Configuration
package A4A.Application.MBTCP_Server_Config is
--------------------------------------------------------------------
-- Modbus TCP Server configuration
--------------------------------------------------------------------
package Server is new A4A.MBTCP_Server
(
Coils_Number => 65536,
Input_Bits_Number => 65536,
Input_Registers_Number => 65536,
Registers_Number => 65536
);
Config1 : aliased Server.Server_Configuration :=
(Server_Enabled => True,
Debug_On => False,
Retries => 3,
Server_IP_Address => To_Bounded_String ("127.0.0.1"),
Server_TCP_Port => 1503); -- (1)
end A4A.Application.MBTCP_Server_Config;
1 | Modbus TCP Server port : 1503 (default) |
7.5. User objects Definition
package A4A.User_Objects is
--------------------------------------------------------------------
-- User Objects creation
--------------------------------------------------------------------
First_Cycle : Boolean := True;
Output_Byte : Byte := 0; -- (3)
Tempo_TON_1 : TON.Instance;
-- My Tempo TON 1
TON_1_Q : Boolean := False;
Cmd_Byte : Byte := 0; -- (1)
Pattern_Byte : Byte := 0; -- (2)
end A4A.User_Objects;
1 | 8 Input bits are read that form the Command byte, which is also output in 8 Coils. |
2 | 8 Input bits are read that form the Pattern byte. |
3 | 8 Coils are written that reflect the Output byte. |
7.6. User Functions
package body A4A.User_Functions is
--------------------------------------------------------------------
-- User functions
--------------------------------------------------------------------
procedure Map_Inputs is -- (1)
begin
Booleans_To_Byte (Boolean_in00 => MBTCP_IOScan.Bool_Inputs (0),
Boolean_in01 => MBTCP_IOScan.Bool_Inputs (1),
Boolean_in02 => MBTCP_IOScan.Bool_Inputs (2),
Boolean_in03 => MBTCP_IOScan.Bool_Inputs (3),
Boolean_in04 => MBTCP_IOScan.Bool_Inputs (4),
Boolean_in05 => MBTCP_IOScan.Bool_Inputs (5),
Boolean_in06 => MBTCP_IOScan.Bool_Inputs (6),
Boolean_in07 => MBTCP_IOScan.Bool_Inputs (7),
Byte_out => Cmd_Byte);
Booleans_To_Byte (Boolean_in00 => MBTCP_IOScan.Bool_Inputs (8),
Boolean_in01 => MBTCP_IOScan.Bool_Inputs (9),
Boolean_in02 => MBTCP_IOScan.Bool_Inputs (10),
Boolean_in03 => MBTCP_IOScan.Bool_Inputs (11),
Boolean_in04 => MBTCP_IOScan.Bool_Inputs (12),
Boolean_in05 => MBTCP_IOScan.Bool_Inputs (13),
Boolean_in06 => MBTCP_IOScan.Bool_Inputs (14),
Boolean_in07 => MBTCP_IOScan.Bool_Inputs (15),
Byte_out => Pattern_Byte);
end Map_Inputs;
procedure Map_Outputs is -- (2)
begin
Byte_To_Booleans (Byte_in => Cmd_Byte,
Boolean_out00 => MBTCP_IOScan.Bool_Outputs (0),
Boolean_out01 => MBTCP_IOScan.Bool_Outputs (1),
Boolean_out02 => MBTCP_IOScan.Bool_Outputs (2),
Boolean_out03 => MBTCP_IOScan.Bool_Outputs (3),
Boolean_out04 => MBTCP_IOScan.Bool_Outputs (4),
Boolean_out05 => MBTCP_IOScan.Bool_Outputs (5),
Boolean_out06 => MBTCP_IOScan.Bool_Outputs (6),
Boolean_out07 => MBTCP_IOScan.Bool_Outputs (7));
Byte_To_Booleans (Byte_in => Output_Byte,
Boolean_out00 => MBTCP_IOScan.Bool_Outputs (8),
Boolean_out01 => MBTCP_IOScan.Bool_Outputs (9),
Boolean_out02 => MBTCP_IOScan.Bool_Outputs (10),
Boolean_out03 => MBTCP_IOScan.Bool_Outputs (11),
Boolean_out04 => MBTCP_IOScan.Bool_Outputs (12),
Boolean_out05 => MBTCP_IOScan.Bool_Outputs (13),
Boolean_out06 => MBTCP_IOScan.Bool_Outputs (14),
Boolean_out07 => MBTCP_IOScan.Bool_Outputs (15));
end Map_Outputs;
procedure Map_HMI_Inputs is
begin
null;
end Map_HMI_Inputs;
procedure Map_HMI_Outputs is
begin
null;
end Map_HMI_Outputs;
procedure Process_IO is -- (3)
Elapsed_TON_1 : Ada.Real_Time.Time_Span;
begin
if First_Cycle then
Output_Byte := Pattern_Byte;
First_Cycle := False;
end if;
Tempo_TON_1.Cyclic (Start => not TON_1_Q,
Preset => Ada.Real_Time.Milliseconds (500),
Elapsed => Elapsed_TON_1,
Q => TON_1_Q);
if TON_1_Q then
case Cmd_Byte is
when 0 =>
Output_Byte := ROR (Value => Output_Byte, Amount => 1);
when 1 =>
Output_Byte := ROL (Value => Output_Byte, Amount => 1);
when others => Output_Byte := Pattern_Byte;
end case;
end if;
end Process_IO;
end A4A.User_Functions;
User functions are defined to :
1 | get the inputs from the IO Scanner, |
2 | set IO Scanner ouputs, |
3 | process the data. |
7.7. User Application
package body A4A.Application is
procedure Cold_Start is
begin
null;
end Cold_Start;
procedure Closing is
begin
null;
end Closing;
procedure Main_Cyclic is
My_Ident : constant String := "A4A.Application.Main_Cyclic";
begin
Map_Inputs; -- (1)
Map_HMI_Inputs;
-- Playing with tasks interface
Main_Outputs.X := Main_Inputs.A;
Main_Outputs.Y := Main_Inputs.B;
Main_Outputs.Z := Main_Inputs.C;
Process_IO; -- (2)
Map_Outputs; -- (3)
Map_HMI_Outputs;
exception
when Error : others =>
A4A.Log.Logger.Put (Who => My_Ident,
What => Exception_Information (Error));
Program_Fault_Flag := True;
end Main_Cyclic;
procedure Periodic1_Cyclic is
My_Ident : constant String := "A4A.Application.Periodic1_Cyclic";
begin
-- Playing with tasks interface
Periodic1_Outputs.A := not Periodic1_Inputs.X;
Periodic1_Outputs.B := Periodic1_Inputs.Y + 2;
Periodic1_Outputs.C := Periodic1_Inputs.Z + 1;
exception
when Error : others =>
A4A.Log.Logger.Put (Who => My_Ident,
What => Exception_Information (Error));
Program_Fault_Flag := True;
end Periodic1_Cyclic;
function Program_Fault return Boolean is
begin
return Program_Fault_Flag;
end Program_Fault;
end A4A.Application;
The application cyclically :
1 | gets the inputs from the IO Scanner, |
2 | processes the data, |
3 | sets IO Scanner ouputs. |