Resource Scheduler 2.0 Using VARCHART XGantt

Transcription

1 Resource Scheduler 2.0 Using VARCHART XGantt NETRONIC Software GmbH Pascalstrasse Aachen, Germany Phone +49 (0) Fax +49 (0) Copyright 2007 NETRONIC Software GmbH All rights reserved.

2 Table of Contents 1 Introduction to the Sample Application Entering Data and Modifying Settings Operations Setting the Resource Demand of an Operation Considering Start-up and Shut-down times Operations That Cannot be Scheduled Locking Operations Tasks Setting a Planning Strategy Setting the Sequence of Tasks by Priorities Dependencies Between Tasks Resources Creating Resources Assigning Operations to Resources Limited and Unlimited Resources The Efficiency of a Resource Date of Issue: 25. Februar

3 1 Introduction to the Sample Application Resource scheduling is a useful tool for scheduling tasks in order to comply with terms while avoiding an overload of existing resources. Typical fields of application for resource scheduling are production and service. By the example of an application, this manual will explain the fundamentals of resource scheduling using VARCHART XGantt. The application was programmed by using the resource scheduling module of the VARCHART XGantt.NET edition. The same functionality is available in the resource scheduling module of the ActiveX edition. The functions demonstrated in the application sample only represent a section of the entire set of functions available in the modules. The link below allows to directly install the tutorial program. If on your computer the required.net Framework was not yet installed, it will also be installed. On each start the program will check, whether the version on your computer is the latest one and if an update is necessary from the NETRONIC website. This tutorial will give you a first impression of the comprehensive options of the resource scheduler module. If you need support, please do not hesitate to contact our sales and support staff. 3

4 Please start the program NETRONIC Resource Scheduling Tutorial. The Gantt diagram is partitioned into defined sections: In the upper part on the left there is the table which displays the tasks and their operations; right of the table there is the Gantt graph, which graphically displays the tasks and operations below the time scale; the section below the Gantt graph is the histogram, where capacities (red lines) and work loads (gray areas, hatched) of resources are shown. You can modify the ratio between the table and the Gantt graph by dragging the separator bar between them to the left or to the right. After starting the application, the sample shows in its original state a task Task 1, which is worked off by 3 operations. To the operations resources were assigned: Operation 1 uses Timing Resource 1 Operation 2 uses Timing Resource 2 Operation 3 uses Timing Resource 1 The time span within which the operations of a task are allowed to be scheduled are defined by the release date and the due date. The time span is visualised by a green line limited by small green triangles at its beginning and its end. To work off a task, consecutive operations have to be run. An operation can only be run if a resource was assigned to it which offers sufficient capacity during operation time. The operations are displayed as yellow bars below a task. The start and end dates of the operations are the results of scheduling. The start date of the first operation and the end 4

5 date of the last operation represent the limits of the total operation time of the task, which is visualised by an ochre bar. Resource capacity is displayed by the red line in the histogram. Non-working times are defined by a calendar and appear as vertical gray stripes in the Gantt graph and in the histogram. The resource capacity during non-working times equals 0. The work loads of the resources that result from scheduling are displayed as gray hatched areas in the histogram. 2 Entering Data and Modifying Settings You can create and delete resources, tasks and operations and modify their features in a dialog to be invoked by the right mouse button while the mouse cursor is on a resource, on a task or on an operation. Alternatively, you can get to the dialog by the Edit menu, selecting the menu item Resource scheduling dialog. By using the button Open... you can load prepared sample files to be used in the Resource Scheduling Tutorial. By the button Save you can save your modifications, and the buttons Add, Copy and Remove serve to accomplish the corresponding actions on resources, tasks and operations. You can re-start the original state by selecting the menu item New in the menu File. On the left, the dialog shows a menu tree, the subtrees of which can be collapsed and expanded. When selecting a menu item, the corresponding properties will appear in the tab on the right. On the top level, you can enter general settings by selecting General or Tasks. The tab General lets you modify general settings. You can set the 5

6 start and end dates of the scheduling period. The planning unit represents the degree of fragmentation of the schedule. By the Visualization tab you can modify the time scale, the height of the lines or of the histogram. 3 Operations Operations are single steps that are run consecutively to work off a task. 3.1 Setting the Resource Demand of an Operation The demand of resources required to run an operation results from the Quantity of a task multiplied by the Load per Item. The duration of an operation is calculated from the resource demand and the available resource capacity over time. Changes of the capacity demand by the Quantity (on the task tab) or by the Load per Item will change the duration of an operation. We will demonstrate this coherence by the below example. Please raise Load per Item of Operation 2 from 1 to 2 on the corresponding tab. Please realize how the operation time prolongs while the occupation of the resource simultaneously expands. 6

7 3.2 Considering Start-up and Shut-down times Start-up and shut-down times before and after an operation may occupy a resource and may thus prolong operation time. Typical start-up and shut-down activities could be changing the tools of a machine or cleaning it after an operation. You can set the required time on the Operation tab by entering a value into Preparation load and Post load. After having reduced the Quantity of Task 1 back to 1, please set a value of 1 to Preparation load and to Post load. In the Gantt-Graph the Preparation load is visualized by a light blue bar and Post load by a light red bar: 7

8 3.3 Operations That Cannot be Scheduled If the resources required to run an operation are not available within due time, a task cannot be scheduled. Please increase the Quantity of Task 1 from 1 to 2. A cross-hatch pattern in the operations indicates that they could not be scheduled. A red color marks the actual operation which could not be scheduled. A black color indicates, that the operation basically could have been scheduled, but failed since one of the succeeding operations required more capacity than was available. 8

9 The cross-hatched operations can only be scheduled, if more capacity is made available. Different options could solve the problem: The due date could be shifted into the future by 2 days. Alternatively, the weekend could be declared as working time. Also, a combination of both options could help: The due date could be shifted by one day and a working shift could be introduced on Saturday (March, 10 th ). Move the Due date into the future by one day by dragging the green triangle towards the right. Saturday can be turned into a working day by invoking the pop-up menu by the right mouse button when the cursor is on March, 10 th in the time scale. Please select the option Change to non-workday from the menu. If bottlenecks occur regularly in your system, you should think about a general increase of your resource capacity. You could employ more staff or invest in additional 9

10 machinery. Please take a look at the resulting scenario after doubling the capacity of the two resources. Increase the Capacity in Timing Resource 1 and Timing Resource 2 from 1 to Locking Operations Within its due time between the release date and the due date, you can lock an operation to a date. Locking an operation may make sense, if the operation already started and is not desired to be dislocated by the scheduling procedure. Please lock the start date of Operation 1 on the corresponding tab by ticking the check box of Start lock date and by entering a date. A locked operation is marked by a red diamond at the beginning of the yellow bar. 10

11 4 Tasks 4.1 Setting a Planning Strategy Up to this point, a task used to be scheduled as soon as a resource offered sufficient capacity. But this strategy is only one out of two available planning strategies: 1. The ASAP planning strategy: within its scheduling period, a task is scheduled As Soon As Possible, i.e., as soon as resource capacity is available. 2. The JIT planning strategy: within its scheduling period, a task is scheduled Just In Time so that it is finished exactly on the due date. Please re-load the original state by selecting the option New in the menu File. On the tab Tasks, the global planning strategy had been pre-set to ASAP. If you now change it to JIT, the task will be moved to the end of the scheduling period: 11

12 4.2 Setting the Sequence of Tasks by Priorities The sequence by which tasks are scheduled is controlled by priorities that were assigned to tasks. The larger the priority, the more important the task is and the better its chance to be considered. The lowest priority is 0. If tasks are of equal priority, the order of their creation will be used as a criterion for their sequence during the scheduling procedure. Now, please create another task Task 2 by selecting Task 1 and by using the button Copy. Both, Task 1 and Task 2 are of equal priority. Task1 is scheduled after Task 2, since the sequence of creation determines the order if the priority is equal. Task 1 was created before Task 2, so Task 1 is scheduled preferentially, i.e. later than Task 2. Now, please change from JIT to ASAP to visualize the consequence of the planning strategies. Task 1 remains the preferred task and is scheduled earlier than Task 2. 12

13 Now, please change the priority of Task 2 from 0 to 1. Now Task 2 is favored and is scheduled before Task 1: 4.3 Dependencies Between Tasks A possible dependency between tasks may consist of the condition, that one task has to be finished before another one can start. Dependencies between tasks can be visualized by links. Please change from the Pointer mode to the Precedence creation mode by the pop-up menu of the Gantt graph. 13

14 The mouse cursor takes on the shape of a pencil and allows to draw a link from the last operation of a task to the first operation of a different task. Please draw a link from the last operation of Task 2 to the first operation of Task 1. If desired, you can also delete the link by the pop-up menu. The direction of the link determines which one of the tasks will be worked off first and which one succeedingly. The task where the link starts must have finished before the task where the link ends can start. 5 Resources There are different types of resources. Timing resources determine the amount of time required to finish an operation. The total capacity required by an operation is transposed into resource capacity along time. In order to be scheduled, an operation requires exactly one timing resource. Work resources represent additional conditions that need to be fulfilled in order to have operations accomplished. They are optional and do not influence the time or duration of an operation. An example of a work resource may be the operator of a machine. 14

15 5.1 Creating Resources Please reproduce the original state by invoking the item New in the menu File. After selecting the subtree Timing Resources in the menu, you can add a resource by the button Add. Any resource added becomes immediately visible in the histogram. 5.2 Assigning Operations to Resources In the menu tree, please mark the item Timing Resource 1 below Operation 3. We are now going to assign a different resource to Operation 3. In the tab Timing resource assignment, select Timing Resource 3 in the field Timing resource. 15

16 5.3 Limited and Unlimited Resources A resource may have a limited or an unlimited capacity. A resource of unlimited capacity is available for an unlimited number of times; there is never a bottleneck. For example, you can visualize the transport of products in containers, assuming an unlimited number of containers. Please create Task 2 by copying Task 1. For all resources, change the capacity type from Finite to Infinite. The color of the capacity limit automatically will turn from red to green. Task 1 and Task 2 can be worked off simultaneously, since the resources will not produce a bottleneck. 16

17 Above the capacity limit, red-hatched areas have appeared. They indicate that the operations could be run if a twofold capacity of the resources (or two of each) were available. By using infinite resources you can very easily simulate what-if scenarios. 17

18 5.4 The Efficiency of a Resource A resource can increase or decrease its efficiency, for example at 110% or at reduced power. The operation time will correspondingly decrease or increase, respectively. If you reduce the efficiency of Resource 1 from 100% to 50%, the operation time will double. 18

19 6 Glossary Capacity Available volume of performance to work off an -> operation. Often expressed in time units, during which a resource is available, for example hours or minutes of occupation. Due date Final date of the -> processing time window, at which a task must have been worked off. Efficiency (of a -> resource) Effectiveness (in percent), by which a resource works. Example: A machine can lower its efficiency to 50% or rise it even above 100%. Gantt Diagram The core of a Gantt diagram is the -> Gantt graph. A diagram contains additional sections, such as a table or a -> histogram, that provide additional information. Gantt Graph Graphical visualization of activities over time. A Gantt graph mostly consists of a horizontal time axis, below which activities in the shape of bars are displayed. Histogram A histogram adds up activities of a Gantt graph and displays them graphically as a work load curve. It may show several curves composing of defined activities. Load per item Resource capacity required to produce an item. Often expressed as time units, for example minutes of processing time on a machine. Locking An operation can be locked to its start date. It will then be excluded from the scheduling process. Operation Part of task, which can be worked off by a -> resource. An operation is scheduled within the -> scheduling period of the task. Planning Strategy Tasks and operations within their scheduling period can either be scheduled as soon as possible (ASAP) or just in time (JIT) before the -> due date. Preparation load and post load Times, by which a resource is occupied, but does not work. Example: Tooling a machine before an operation starts or cleaning a machine after an operation. 19

20 Processing time window Time span between the -> release date and the -> due date. Within this time span a task has to be worked off. Quantity Volume of a task which can be quantified in units. Example: 100,000 sheets of paper to be processed. Release Date Start date of the scheduling period, from which on it is allowed to be worked off. Resource Entity that provides working power (machine, human being, animal etc.), by which tasks can be worked off. Task Job, that consists of one or more steps (-> operations) and that has to be worked off within a certain time (-> scheduling period). Example: in the printing industry, sheets of paper are cut, printed and bound. The task mentioned consists of three operations. Work Load Volume of work by which a resource is occupied at a certain time. Example: A machine can process 100,000 sheets during a day, so its work load on that day is 100,