DDAS Scheduler Library Manual

About this documentation

This documentation provides essential information for working with components of the DDAS software ecosystem. It is intended for software developers and machine manufacturers who integrate, validate, and operate DDAS function blocks within CODESYS‑based applications.

Note!

Before installing or configuring any software, ensure that you have read and understood the operating instructions of all relevant hardware devices!

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Further information can be found at: https://www.ddas.digital

This manual is part of the DDAS library collection, which includes documentation for license management, date and time handling, scheduling, equipment performance, and other functional modules:

Document history

General

Library

This library support batch‑oriented manufacturing by calculating required production time, estimating batch completion while considering production and break schedules, and providing real‑time and historical information about active schedules.

They use product targets and actual machine performance to enable accurate time estimation, schedule awareness, and event triggering.

The provided data supports operator displays, production planning, synchronization of automation logic, scheduling of downstream processes, and proper handling of shifts and breaks.

The library includes the following user function blocks:

• GetBuildTime

• GetBatchScheduledEndTime

• GetSchedule

• UpdateInterval

GetBuildTime

Calculates the total production time required to complete all target products based on actual machine performance. It provides a pure build-time estimate without considering schedules or breaks, supporting production planning, operator displays, and downstream process coordination.

GetBatchScheduledEndTime

Estimates the expected batch end time by combining calculated build time with configured production schedules and planned breaks. It enables realistic batch completion forecasts for planning, scheduling, and triggering follow‑up automation actions.

GetSchedule

Provides real‑time and historical information about the currently active production or break schedule, including timing, duration, and start/end trigger signals. It supports schedule monitoring, synchronization of production logic, operator visualization, and correct handling of shifts and breaks in automated systems.

UpdateInterval

Controls the update rate of date and time outputs by applying a configurable interval filter, ensuring that values are refreshed only when necessary. It is designed to reduce unnecessary high-frequency updates, improving readability and usability for operator displays.

Detailed descriptions of the function blocks and their relevant dependencies are provided in the following chapters.

Licensing Concept

All libraries require a valid license. Each license is based on three mandatory keys:

• SiteCode
  Provided by the user (e.g. ‘DDAS-Site-License’)

• LibraryGuid
  Delivered with the library (e.g. ‘{LIB-DDAS-D5BA612E}’)

• LibraryActivationKey
  Issued by DDAS (e.g. ‘EDB86DA0’)

License Activation Mechanism

To activate a library license, one instance of the function block Get_Lib_License must be called for each licensed library.
This function block is part of the DDAS_LicenseManager_Lib library.

Licensing Process

The following steps are required to license and use a library:

1. The user selects the required libraries.

2. The user integrates the selected libraries into a test project or uses the provided demo program and evaluates them using the time‑limited demo license.

3. If the user intends to use the library function blocks in a machine application, the library is ordered and the selected SiteCode is sent to DDAS.

4. DDAS provides the corresponding LibraryActivationKey.

5. In the machine application, the user instantiates the function block Get_Lib_License once for each library and assigns all required license keys to activate the library license.

6. After successful activation, all function blocks of the licensed library can be implemented and executed.

Note: Detailed information on how to use the function block Get_Lib_License is provided in the software manual of the library DDAS_LicenseManager_Lib.

Note: The function Get_sError is available in every library and provides access to the error description and enumeration corresponding to a function block’s error code, when required.

FB GetBuildTime

General Information

This chapter describes the function block GetBuildTime.

Function Block Name: GetBuildTime

Library: DDAS_Scheduler_Lib

Dependent Codesys libraries: Util

CODESYS Version Compatibility: CODESYS V3.5 and higher

License / Usage Restrictions: Requires valid full or demo library license

Purpose & Scope

This function block GetbuidTime calculates the remaining time required to complete a production batch based on defined target quantities and actual machine performance

This function block is typically used in batch-oriented manufacturing applications to calculate the build time required to complete all products. The calculation is based on defined product targets and actual machine performance and does not consider production schedules or breaks.

Typical Use Cases

The resulting information can be used for operator displays, production planning, scheduling of downstream processes, or triggering subsequent automation steps.

Functional Overview

When enabled, the GetBuildTime function block executes its calculation cyclically and uses the current local date and time internally.

The calculation is based on the planned product target, the number of products already produced, the machine’s nominal throughput, and the effective performance derived from the OEE value.

Production schedules, breaks, and shift models are not considered.

The result provides a precise time‑to‑completion value and indicates when the batch target has been reached or exceeded.

Additional status outputs support license verification and diagnostic handling.

Key inputs include:

• Batch definition inputs, such as the target quantity and the number of products already produced.

• Machine performance inputs, including products per minute and OEE.

• Control and timing inputs, such as enable signals, and local date and time.

Key outputs include:

• The calculated remaining build time until the batch target is reached.

• A status indicator signalling when the batch target has been achieved or exceeded.

• Diagnostic and licensing outputs indicating license validity and any error or warning conditions with detailed status information.

Interface Description

Function block Inputs and Outputs

Execution & Timing Behaviour

The function block is intended to be executed cyclically in a task context.

Timing precision depends on the configured task cycle time and target platform

Error Handling & Diagnostics

If an internal error, a library issue, or a licensing problem occurs, xError is set to TRUE and iErrorID provides the corresponding error code. Detailed descriptions of the error codes are defined in the enumeration eError.

Assumptions & Limitations

Accuracy depends on the system clock. Hardware‑dependent behavior may vary across different CODESYS platforms.

The build time calculation is restricted to a 49-day window. If the required build time extends beyond this period, the function block cannot provide a valid result.

Before ordering this library, please verify the correct functionality of the library function block in your target system.

Example Implementation

Declaration and Call of the Function Block GetBuildTime:

GVL_Par:

VAR_GLOBAL

END_VAR

VAR

fb_GetBuildTime : DDAS_SL.GetBuildTime;

END_VAR

FB call in structure text:

fb_ GetBuildTime(

xEnabled := TRUE,

xActive := GVL_Par. xExternActiveBatch,

lrBatchTarget := GVL_Par. lrBatchTarget,

lrActualBuild := GVL_Par. lrActualBuild,

rProductsPerMin := GVL_Par. rProductsPerMin,

rOEEpercent := GVL_Par. rOEEpercent,

dtLocalDateTime := GVL_Par. dtLocalDateTime

);

FB call in continuous function chart diagram:

Function block sample input and output parameter:

Screenshot example in Online / Monitor mode

Demo Visualisation

FB GetBatchScheduledEndTime

General Information

This chapter describes the function block GetBatchScheduledEndTime.

Function Block Name: GetBatchScheduledEndTime

Library: DDAS_Scheduler_Lib

Dependent Codesys libraries: Util

CODESYS Version Compatibility: CODESYS V3.5 and higher

License / Usage Restrictions: Requires valid full or demo library license

Purpose & Scope

This function block GetBatchScheduledEndTime estimates the batch end time based on the calculated batch build time and the configured production and break schedules.

This function block is typically used in batch-oriented manufacturing applications where the batch end time must be estimated while considering production schedules and planned breaks. The estimation is based on defined product targets, actual machine performance, and the calculated build time.

Typical Use Cases

The calculated batch end time can be used for operator displays, production planning, scheduling of downstream processes, or triggering subsequent automation steps.

Functional Overview

When enabled, the GetBatchScheduledEndTime function block estimates the expected batch end date and time based on the remaining build time and the configured production and break schedules.

The calculation uses the current local date and time, the active weekday, and the user‑defined shift and break configuration. The estimation is based on the provided remaining build time, which reflects defined product targets and actual machine performance.

Unlike pure build‑time calculations, this function block considers production schedules and planned breaks to determine a realistic batch end time.

The result provides the calculated batch end date and time, the total remaining time until batch completion, and the accumulated scheduled break time within this period. Additional status outputs indicate calculation validity, license status, and diagnostic information.

Key inputs include:

• Build time input, providing the remaining time required to complete the batch.

• Schedule configuration input, defining production shifts and planned breaks.

• Time reference inputs, such as local date and time and the current day of the week.

• Control input, enabling execution of the function block.

Key outputs include:

• The estimated batch end date and time, considering production and break schedules.

• The total remaining time to batch end, including scheduled breaks.

• The accumulated break time until batch completion.

• A validity indicator, signalling whether the calculated batch end time is valid.

• Diagnostic and licensing outputs, indicating license validity and any error or warning conditions with detailed status information.

.

Interface Description

Function block Inputs and Outputs

Execution & Timing Behaviour

The function block is intended to be executed cyclically in a task context.

Timing precision depends on the configured task cycle time and target platform

Error Handling & Diagnostics

If an internal error, a library issue, or a licensing problem occurs, xError is set to TRUE and iErrorID provides the corresponding error code. Detailed descriptions of the error codes are defined in the enumeration eError.

Assumptions & Limitations

Accuracy depends on the system clock. Hardware‑dependent behavior may vary across different CODESYS platforms.

The batch end time estimation is restricted to a one‑week calculation window. If the required build time extends beyond this period, the function block cannot provide a valid result.

Before ordering this library, please verify the correct functionality of the library function block in your target system.

Example Implementation

Declaration and Call of the Function Block GetBatchScheduledEndTime:

GVL_Par:

VAR_GLOBAL

END_VAR

VAR

fb_GetBatchEndTime : DDAS_SL.GetBatchScheduledEndTime;

END_VAR

FB call in structure text:

fb_GetBatchEndTime(

xEnabled := TRUE,

ltTimeToBuildIn := fb_GetBuildTime. ltTimeToBuild,

dtLocalDateTime := GVL_Par. dtLocalDateTime,

uiDayOfWeek := GVL_Par. uiDayOfWeek,

scPar_Schedule := GVL_Par. scPar_Schedule

);

FB call in continuous function chart diagram:

Function block sample input and output parameter:

Screenshot example in Online / Monitor mode

Demo Visualisation

FB GetSchedule

General Information

This chapter describes the function block GetSchedule.

Function Block Name: GetSchedule

Library: DDAS_Scheduler_Lib

Dependent Codesys libraries: Util

CODESYS Version Compatibility: CODESYS V3.5 and higher

License / Usage Restrictions: Requires valid full or demo library license

Purpose & Scope

The function block GetSchedule provides information about the currently active production and break schedule. It includes the start and end times of the active schedule, an indication of whether a schedule is active, the duration of the active schedule, start and end cycle trigger bits, as well as information about previous schedules.

This function block is typically used in manufacturing and production automation systems to monitor and evaluate the currently active production and break schedule. It provides real‑time information about schedule start and end times, schedule activity status, and duration, as well as trigger signals for schedule start and end events. The function block can also supply historical schedule information for analysis and reporting.

Typical Use Cases

The scheduler output can be used to synchronize production logic, control machine states, and support operator displays. It enables accurate production planning and ensures the correct handling of breaks, shift changes, and batch transitions within automated processes.

In addition, the scheduler data is highly relevant for Overall Equipment Effectiveness (OEE) calculations. Since OEE is based on planned and unplanned production schedules, reliable schedule start and end triggers are required to correctly initiate and terminate shift‑ and batch‑level calculations. The recorded scheduler information also supports the creation of historical production records for performance analysis and reporting.

Scheduler Settings

The shift calendar supports configuration of up to three shifts per day, with a maximum of nine breaks distributed across the defined shifts.

Activation of the scheduling system is controlled via the scPar_Schedule structure. This structure allows deactivation of the entire schedule, individual days, or specific shifts as required.

The example configuration illustrates a continuous 24-hour operation, where the schedule spans from 06:30 to 06:30 on the following day.

In this case, a single shift is configured to cover the full duration, resulting in only one active shift per day.

The following example demonstrates a configuration with three active shifts per day.

The same principles apply to the configuration of the up to nine breaks per day.

Configurations in which one shift ends at 14:30:00 and the subsequent shift begins at 14:30:00 are permitted. In such cases, the scheduler assigns the full second at 14:30:00 to the active (ending) shift. The subsequent shift will therefore begin at 14:30:01.

Alternatively, configurations in which one shift ends at 14:29:59 and the subsequent shift begins at 14:30:00 are also valid.

Note: Overlapping schedules, where one shift ends at 14:30:01 and the subsequent shift begins at 14:30:00, are not permitted. Such configurations may result in errors or unintended scheduling behaviour.

Schedule in Batch Mode

In Batch mode, an active shift schedule is not required, as batch start and end events control the activation and deactivation of the schedule.

Typically, in this mode, the xHideShift input of the GetSchedule function block should be set to TRUE. This ensures that the day and shift configurations defined in the input structure scPar_Schedule are ignored.

In general, defining a production shift schedule in Batch mode can be useful for indicating planned production periods and for calculating estimated batch end times based on expected production availability. However, this schedule should not be used to determine the active schedule state. Instead, batch activity shall be indicated exclusively via the xBatchActive input.

A combination of Batch mode and shift scheduling is not recommended. However, it may be used in specific applications requiring a mixed mode of batch- and shift-based scheduling.

Active break schedules may still be required and are processed in addition to the xBreakActive input, which is used to indicate special or unplanned breaks. The xHideShift input of the GetSchedule function block does not affect the processing of break schedules.

Functional Overview

The GetSchedule function block evaluates and manages the currently effective production schedule within an automation system. Its core purpose is to determine which schedule is active at a given moment—shift, batch, or break—and to provide a consistent, real‑time representation of the scheduling state to the rest of the control application.

The block combines time‑based schedule evaluation with external control signals. It assesses user‑configured shift and break definitions against the current local date, time, and weekday, while also allowing batch and break schedules to be started or stopped explicitly by external logic. This makes it suitable for both calendar‑driven operation (shifts and planned breaks) and event‑driven operation (batches and ad‑hoc breaks).

At runtime, GetSchedule continuously determines:

• Whether any production schedule is currently active

• Whether an active schedule represents normal production or a break

• The effective start and end times of the active schedule

• The total duration of the schedule

• Transitions such as schedule start and schedule end

Break schedules may temporarily interrupt or overlay active production schedules, while batch schedules can be initiated independently of fixed shifts when required. Shift schedules can also be deliberately suppressed, enabling batch‑only operation modes.

In addition to the current state, the function block maintains historical context, preserving information about previously active schedules. This enables reliable downstream use for reporting, analysis, and traceability without requiring additional logic elsewhere in the application.

The function block also handles diagnostics and licensing status, ensuring that schedule evaluation operates only when valid and providing clear error or status feedback if abnormal conditions occur.

Overall, GetSchedule acts as a centralized scheduling authority within the automation software. It decouples time‑ and schedule‑related rules from machine control logic, allowing production sequencing, machine enable states, operator messages, and data collection to remain synchronized with shifts, batches, and breaks in a safe and deterministic way.

.

Interface Description

Function block Inputs and Outputs

xHideShifts*:
When production operates in batch mode which is in the most cases the situation, the weekly production schedule is typically used only to determine the batch end time. Actual production is executed in batches and takes place within the scheduled production period.

The scheduler output records the actual start and end times of the batch, rather than the start and end times of the scheduled production period.

xBatchActive*:

When this input is FALSE and xHideShifts is also FALSE, the scheduler output records the start and end times of the scheduled production period based on the user‑defined production settings in scPar_Schedule.

Structures

scScheduleInfo

This structure contains the full output information of the function block related to the currently and historical active schedule.

scScheduleActive

This structure contains the output information of the function block related to the currently active schedule.

scStartEndDateTime

This structure contains the date time output information of the function block related to the currently active schedule.

scScheduleHistory

This structure contains the output information of the function block related to the history of active schedule.

Note: The structures scScheduleHistory[x].scSchedule and scBreakHistory[x].scSchedule provide valid information only when a shift or break schedule is used. If batch-based or external breaks are applied instead, these structures do not contain valid data, as such batches or breaks are not planned or scheduled events.

Execution & Timing Behaviour

The function block is intended to be executed cyclically in a task context.

Timing precision depends on the configured task cycle time and target platform

Error Handling & Diagnostics

If an internal error, a library issue, or a licensing problem occurs, xError is set to TRUE and iErrorID provides the corresponding error code. Detailed descriptions of the error codes are defined in the enumeration eError.

Assumptions & Limitations

Accuracy depends on the system clock. Hardware‑dependent behavior may vary across different CODESYS platforms.

The shift calendar is limited to a 7‑day period, with up to three shifts and nine breaks configurable per day. Additionally, the scheduler maintains a history of the most recent ten schedule events.

Before ordering this library, please verify the correct functionality of the library function block in your target system.

Example Implementation

Declaration and Call of the Function Block GetSchedule:

GVL_Par:

VAR_GLOBAL

END_VAR

VAR

fb_GetSchedule : DDAS_SL.GetSchedule;

END_VAR

FB call in structure text:

fb_GetSchedule(

xEnabled := TRUE,

xHideShift := GVL_Par. xHideShift,

xBatchActive := GVL_Par. xExternActiveBatch,

xBreakActive := GVL_Par. xExternBreakBatch,

dtBatchEndTime := GVL_Par. dtBatchEndTime,

sBatchDescription := GVL_Par. sJobID,

sBreakDescription := GVL_Par. sBreak,

dtLocalDateTime := GVL_Par. dtLocalDateTime,

uiDayOfWeek := GVL_Par. uiDayOfWeek,

scPar_Schedule := GVL_Par. scPar_Schedule

);

FB call in continuous function chart diagram:

Function block sample input and output parameter:

Screenshot example in Online / Monitor mode active shift/batch and break information.

Screenshot example in Online / Monitor mode history shift/batch and break information.

Demo Visualisation

FB UpdateInterval

General Information

This chapter describes the function block UpdateInterval.

Function Block Name: UpdateInterval

Library: DDAS_Scheduler_Lib

Dependent Codesys libraries: n/a

CODESYS Version Compatibility: CODESYS V3.5 and higher

License / Usage Restrictions: Requires valid full or demo library license

Purpose & Scope

This function block implements an interval-based filter for date and time values, limiting update frequency to match user or display requirements and avoiding excessive cyclic refreshes.

Typical Use Cases

When date and time information is updated cyclically at a high frequency, directly refreshing the display can be inconvenient for the operator.

This function block provides a filter to update date and time values only as required for the user, reducing unnecessary display updates.

Functional Overview

The UpdateInterval function block controls the update rate of a date and time signal by applying an interval-based and event-driven filter. It is intended to prevent unnecessary high-frequency updates, improving readability and usability for operator displays and downstream consumers.

When enabled, the function block accepts an input date/time value and updates the output either periodically based on a configurable time interval or immediately in response to dedicated event signals.

Multiple event inputs allow external triggering of updates independent of the cyclic interval. Diagnostic and licensing status outputs are provided to support reliable operation and integration.

Additional status outputs support license verification and diagnostic handling.

When enabled via xEnabled, the function block processes the incoming date and time value provided at dtDateTimeIn.

The update of the output date and time is controlled either by a configurable cyclic interval (tUpdateInterval) or by event-driven triggers.

Four independent event inputs (xEventUpdate1 to xEventUpdate4) allow immediate updating of the output on rising or falling signal edges, enabling external control over when updates occur.

The filtered and conditionally updated date and time value is made available at dtDateTimeOut.

The function block additionally provides the xLicensed output to indicate whether a valid full or demo license is active. Any detected error or warning condition is signalled via xError, with further diagnostic details provided through the iErrorID output.

Interface Description

Function block Inputs and Outputs

Execution & Timing Behaviour

The function block is intended to be executed cyclically in a task context.

Timing precision depends on the configured task cycle time and target platform

Error Handling & Diagnostics

If an internal error, a library issue, or a licensing problem occurs, xError is set to TRUE and iErrorID provides the corresponding error code. Detailed descriptions of the error codes are defined in the enumeration eError.

Assumptions & Limitations

Accuracy depends on the system clock. Hardware‑dependent behavior may vary across different CODESYS platforms.

Before ordering this library, please verify the correct functionality of the library function block in your target system.

Example Implementation

Declaration and Call of the Function Block UpdateInterval:

GVL_Par:

VAR_GLOBAL

END_VAR

VAR

fb_ UpdateInterval : DDAS_SL. UpdateInterval;

END_VAR

FB call in structure text:

fb_ UpdateInterval(

xEnabled := TRUE,

dtdateTimeIn := GVL_Par_SL.dtBatchEndTime,

xEventUpdate1 := GVL_Par_SL.xUpdate1,

xEventUpdate2 := GVL_Par_SL.xUpdate2,

dtLocalDateTime := GVL_Par_SL.tUpdateInterval

);

FB call in continuous function chart diagram:

Function block sample input and output parameter:

Screenshot example in Online / Monitor mode

Global

Structures

scPar_Schedule

This structure provides the user‑configured shift, production, and break schedules.

scScheduleShiftActivated

This structure provides the user‑configured production shift schedules.

scScheduleBreakActivated

This structure provides the user‑configured production break schedules.

scParInSchedule

This structure provides the user‑configured single production schedules.

Demo Visualisation

Shift Schedule

Break Schedule

Enumerations

eScheduleEvent

Schedule event type enumeration.

eError

Library Possible Error Codes and Descriptions.

Global Variable

GVL_Constant_Scheduler

Library scheduler constants.

GVL_LibGuide

This Global Variable List provides the library license GUID. Relevant input parameter for the function block DDAS_LM.Get_Lib_License, required to activate the library license in conjunction with the activation key and side code.

Example Implementation

The following screenshots illustrate a complete implementation of the library function blocks, including the license function block and a simple set/reset function block used to start and stop a batch.

The current local date, time, and day of the week can be obtained using the DDAS function block DDAS_DT.GetDateTimeInfo from the DDAS_DateTime_lib library.

Your Feedback Matters

These instructions have been prepared to the best of our knowledge and belief to provide you with the highest possible level of support when working with our product.

Despite our best efforts, we may not always fully achieve this objective. If you identify any issues or have suggestions for improvement, we would greatly appreciate your feedback.

Please send your comments or criticism in a short e‑mail to:

support@ddas.digital

Thank you for your support.

Your DDAS Application Software Team