Definitions: PLC system start-upPermalink

Cold start

The AC500-eCo does not use a battery for buffering the operand areas specified below, hence the “cold start” mode does not exist in this product.

  • A cold start is performed by switching power OFF/ON if no battery is connected.

  • All RAM memory modules are checked and erased .

  • If no user program is stored in the flash EPROM, the default values (as set on delivery) are applied to the interfaces.

  • If there is a user program stored in the flash EPROM, it is loaded into RAM.

  • The default operating modes set by the PLC configuration are applied.

Warm start

  • A warm start is performed by switching power OFF/ON with a battery connected.

  • All RAM memory modules are checked and erased except of the buffered operand areas and the RETAIN variables .

  • If there is a user program stored in the flash EPROM, it is loaded into RAM.

  • The default operating modes set by the PLC configuration are applied.

  • By booting the CPU the connected IO modules are re-initialized and parameterized, therefore the IO output fails for a short time.

RUN -> STOP

  • RUN -> STOP means pressing the RUN function key on the PLC while the PLC is in run mode (AC500 PLC display “run”, AC500-eCo PLC "RUN LED" is ON).

  • If a user program is loaded into RAM, execution is stopped.

  • The behavior of outputs in stop state is configurable. Double click on PLC_AC500_V3 in the project tree. In the “PLC_AC500_V3” tab click on “PLC Settings”.

    • To activate update of I/O while in stop state, click the checkbox left of “Update I/O while in stop”.

    • To specify the behavior of the outputs in stop state, select an option in the pull down menu right of “Behavior for outputs in stop”. Options are:

      “Keep current values”

      “Set all outputs to default”

      “Execute program” (If the “Execute program” option is selected, the “Input Assistant” must be opened via the [...] button and a program must be selected which is executed exactly once.)

  • Variables keep their current values, i.e., they are not initialized.

  • The AC500 PLC display changes from “run” to “StoP”, AC500-eCo "RUN LED" changes from ON to OFF.

START -> STOP

  • START -> STOP means stopping the execution of the user program in the PLC's RAM using the menu item "Online/Stop" in the programming system.

  • The behavior of the outputs in stop state is configurable. Double click on PLC_AC500_V3 in the project tree. In the “PLC_AC500_V3” tab click on “PLC Settings”.

    • To activate update of I/O while in stop state, click the checkbox left of “Update I/O while in stop”.

    • To specify the behavior of the outputs in stop state, select an option in the pull down menu right of “Behavior for outputs in stop”. Options are:

      “Keep current values”

      “Set all outputs to default”

      “Execute program” (If the “Execute program” option is selected, the “Input Assistant” must be opened via the [...] button and a program must be selected which is executed exactly once.)

  • Variables keep their current values, i.e., they are not initialized.

  • The AC500 PLC display changes from “run” to “StoP”.

Reset

  • Performs a START -> STOP process.

  • Preparation for program restart, i.e., the variables (VAR) (exception: RETAIN variables) are set to their initialization values.

  • Reset is performed using the menu item "Online/Reset" in the programming system or pressing the function key RUN for ≥ 5 s in STOP mode.

Reset (cold)

  • Performs a START -> STOP process.

  • Preparation for program restart, i.e., the variables (VAR) (also RETAIN variables) are set to their initialization values.

  • Reset (cold) is performed using the menu item "Online/Reset (cold)" in the programming system.

Reset (original)

  • Resets the controller to its original state (deletion of flash, SRAM, communication module configurations and user program!).

  • Reset (original) is performed using the menu item "Online/Reset (original)" in the programming system.

STOP -> RUN

  • STOP -> RUN means short pressing the RUN function key on the PLC while the PLC is in STOP mode (AC500 PLC display "StoP", AC500-eCo "RUN LED" is ON). "RUN LED" is OFF of the toggle switch of an AC500-eCo CPU.

  • If a user program is loaded into RAM, execution is continued, i.e., variables will not be set to their initialization values.

  • The AC500 PLC display changes from "StoP" to "run", AC500-eCo "RUN LED" changes from OFF to ON.

STOP -> START

  • STOP -> START means continuing the execution of the user program in the PLC's RAM using the menu item "Online/Start" in the programming system.

  • If a user program is loaded into RAM, execution is continued, i.e., variables will not be set to their initialization values.

  • The AC500 PLC display changes from "StoP" to "run", AC500-eCo PLC "RUN LED" changes from OFF to ON.

Download

  • Download means loading the complete user program into the PLC's RAM. This process is started by selecting the menu item "Online/Download" in the programming system or after confirming a corresponding system message when switching to online mode (menu item "Online/Login").

  • Execution of the user program is stopped.

  • In order to store the user program to the user flash memory, the menu item "Online/Create boot project" must be called after downloading the program.

  • Variables are set to their initialization values according to the initialization table.

  • RETAIN variables can have wrong values as they can be allocated to other memory addresses in the new project!

  • A download is forced by the following:

    • changed PLC configuration

    • changed task configuration

    • changed library management

    • changed compile-specific settings (segment sizes)

    • execution of the commands "Project/Clean all" and "Project/Rebuild All".

Online change

  • After a project has changed, only these changes are compiled when pressing the key <F11> or calling the menu item "Project/Build". The changed program parts are marked with a blue arrow in the block list.

  • The term Online Change means loading the changes made in the user program into the PLC's RAM using the programming system (after confirming a corresponding system message when switching to online mode, menu item "Online/Login").

  • Execution of the user program is not stopped. After downloading the program changes, the program is re-organized. During re-organization, no further online change command is allowed. The storage of the user program to the user flash memory using the command "Online/Create boot project" cannot be initiated until re-organization is completed.

  • Online Change is not possible after:

    • changes in the PLC configuration

    • changes in the task configuration

    • changes in the library management

    • changed compile-specific settings (segment sizes)

    • performing the commands "Project/Clean all" and "Project/Rebuild All".

Data buffering

  • Data buffering, i.e., maintaining data after power ON/OFF, is only possible, if a battery is connected for AC500 CPU and the buffering will take place in the flash disk with AC500-eCo CPU. The following data can be buffered completely or in parts:

    • Data in the addressable flag area (%M area)

    • RETAIN variable

    • PERSISTENT variable (number is limited, no structured variables)

  • In order to buffer particular data, the data must be excluded from the initialization process ⮫ “Handling of remanent variables”.