Skip to content

Programmable Logic Controller

Preamble

  • The simulator integrates a physical or virtual PLC into a folio.
  • Communication with the PLC is carried out using the [Modbus/Tcp-IP] protocol (modbus.md)
    • with the local IP address (127.0.0.1) of the Modbus server integrated into the virtual PLC,
    • with the static IP address of the Modbus server integrated into the physical PLC connected to an Ethernet network.
  • This solution makes it possible to use the usual PLC programming tools.
  • Exchange logic client (master) (simulator) <-> server (slave) (api), periodically :
    • the Modbus client (simulator) sends a request to write the simulated SAP inputs to the Modbus server (PLC),
    • the PLC calculates the state of the SAP outputs according to its program and the state of the inputs received,
    • the Modbus client (simulator) sends a request to read the outputs calculated by the program to the Modbus server (PLC),
    • the simulator updates the SAP status.
  • PLCs tested :
    • M221 Schneider Electric function codes 3,16 and 23, integrated Modbus server
    • M340 Schneider Electric function codes 3 and 16, integrated modbus server
    • Unilogic Unitronics function codes 3,16 and 23, Modbus server configuration required

  • CODESYS Control Win CODESYS 3.5, codes 3,16 et 23, Modbus server configuration required

  • Only holding registers are used.

    • 48 registers (16-bit word) are allocated:
      • 24 registers for outputs, table start address: QW_address = 0,
      • 24 registers for inputs, table start address: IW_address = 24.
    • The variables used in the program are assigned directly in the Modbus I/O mapping.
    • The parameter writable is ticked to authorize the server to write to the 24 output registers %QWx.y of modules M0 to M5.

Virtual PLC front panel

  • Each I/O module integrates four input words and four 16-bit output words.
  • These words can be specified as :
    • analog' inputs or outputs,
    • digital inputs or outputs.
  • Finally, each module can manage :
    • up to 64 digital inputs and 64 digital outputs,
    • a mix of digital and analog I/Os, e.g. module 0:
      • %QW0.0 -> 16-bit word for an 'analog' output
      • %QW0.1 -> 16 bits usable for 16 digital outputs
      • %IW0.0 -> 16 bits usable for 16 digital inputs

The following examples illustrate the use of dE/S modules.

M221 Elevator example

Files :

  • us15 - demo_elevator_M221.xrs
  • us15 - demo_elevator_M221.smbp (Ecostruxure)

Preparation side Simulator

  • Elevator control requires 8 digital inputs and 4 digital outputs. An M221 type TM221CE16R can be used, with 9 digital inputs and 7 relay outputs.
  • Addressing of digital inputs: %I0.0, %I0.1, %I0.2, %I0.3, %I0.4, %I0.5, %I0.6, %I0.7, %I0.8
  • Output addressing: %Q0.0, %Q0.1, %Q0.2, %Q0.3, %Q0.4, %Q0.5, %Q0.6
  • This example implements 8 input objects and 4 output objects, identifying them with standard PLC addresses.

Input assignment
address mnemonic comment
%I0.0 E3 appel étage 3
%I0.1 E2 appel étage 2
%I0.2 E1 appel étage 1
%I0.3 P1 cabine à létage 1
%I0.4 P2 cabine à létage 2
%I0.5 P3 cabine à létage 3
%I0.6 PF porte cabine fermée
%I0.7 PO porte cabine ouverte

Output assignment

address mnemonic comment
%Q0.0 OUVRIR Open door
%Q0.1 FERMER Close door
%Q0.2 DESCENDRE go down cab
%Q0.3 MONTER go up cab

Preparation side EcoStruxure

The complete program us15 - demo_elevator_M221.smbp is available in the :

Mapping of input/output tables to the exchange table set at start address %MW400 see modbus mapping:
adress MODBUS mapping mnemonic comment
%I0.0 %MW500 :X0 E3 call stage 3
%I0.1 %MW500 :X1 E2 call stage 2
%I0.2 %MW500 :X2 E1 call stage 1
%I0.3 %MW500 :X3 P1 elevator cab on floor 1
%I0.4 %MW500 :X4 P2 elevator cab on floor 2
%I0.5 %MW500 :X5 P3 elevator cab on floor 3
%I0.6 %MW500 :X6 PF cab door closed
%I0.7 %MW500 :X7 PO cab door open
adress MODBUS mapping mnemonic comment
%Q0.0 %MW400 :X0 OUVRIR Open cab door
%Q0.1 %MW400 :X1 FERMER Close cab door
%Q0.2 %MW400 :X2 DESCENDRE go down cab
%Q0.3 %MW401 :X3 MONTER go up cab

In the Programming ->Tools ->Symbols list tab, you'll find the input/output assignments that correspond to the tables above:

PLC program

Start the controller BEFORE starting the simulator by activating the Start simulation and Start controller buttons in the EcoStruxure commissioning tab.

CODESYS analogs I/O

Files :

  • us41 - demo_analog_I-O_CODESYS.smbp
  • us41 - demo_analog_I-O_CODESYS.project (CODESYS 3.5)

Preparation side Simulateur

  • The diagram implements :

    • three analog inputs:
      • %IW1.0 connected to 4-20 mA sensor B2
      • %IW1.1 connected to 4-20 mA sensor B1
      • %IW1.2 connected to 0-10 V sensor AU1
    • two analog outputs:
      • %QW2.0, 0-20 mA current output
      • %QW2.1, voltage output 0-10 v

  • The grapher Grapher is parameterized to display the evolution of the %QW2.0 output

    • Vqw2_0.value.5
      • Vqw2_0 -> voltmeter name
      • value -> display of measured value
      • 5 -> voltmeter rating (250 * 20e-3)* 20e-3)

  • The program in the controller adjusts the sawtooth period using the potentiometer on the AU1 sensor connected to %IW1.2.

Preparation side CODESYS

  • Variables are assigned directly in the modbus I/O mapping Modbus configuration

    • %IW1.0 -> IW1_0
    • %IW1.1 -> IW1_1
    • %IW1.2 -> IW1_2

  • ST code with all I/O registers for visualization

  • CODESSYS running

    • F11 (create code)
    • Alt-F8 (connect) the CODESYS Control Win Systray controller must be running
    • F5 (start)

CODESYS box sorting

Files :

  • us42 - demo_box_sorting_CODESYS.smbp
  • us42 - demo_box_sorting_CODESYS.project (CODESYS 3.5)

Preparation side Simulateur

Preparation side CODESYS

  • Variable assignment is done directly in the modbus I/O mapping Modbus configuration

  • SFC preparation

  • ST code with all I/O registers for visualization

  • CODESSYS at runtime

Building a PLC object

  • A PLC is built with the elementary objects :
    • input# for digital inputs,
    • output# for digital outputs,
    • analog_input# for analog inputs,
    • analog_output# for analog outputs,
    • plc_supply# for PLC power supply.
  • All I/Os have the plc_supply object as their parent, in order to link the supply of these I/Os to the PLC power supply.
  • The MODBUS server is implicitly attached to the PLC in place in the schematic.
  • Only one PLC can be placed in the schematic.
  • Examples of PLCs are available in the folder blocs_simulables, using the WinRelais command 'Open a block'.

All these automaton footprints can be adjusted and modified as required.

Logic Input/Output

input, output library _api
%Ir.v or %Qr.v r = [0,5] v = [0,31]
parent = object name plc_supply#

Analog inputs

analog_input library _api
%IWr.v r = [0,5] v = [0,3]
parent = object name plc_supply#
input_type = U ou I
input_range = (min,max) V [-10,10] V or (min,max) mA [0, 20] mA
input_scale = min,max [-32768, 32767]

Analog Outputs

analog_output library _api
%QW0.0 r = [0,5] v = [0,3]
parent = object name plc_supply#
output_type = U or I
output_range = (min,max) V [-10,10] V or (min,max) mA [0, 20] mA
output_scale = min,max [-32768, 32767]