Block Solution for PLC Cycle Time Monitoring SIMATIC PCS 7 V6.0 SP3 and higher https://support.industry.siemens.com/cs/ww/en/view/22000962 Siemens Industry Online Support

This entry is from the Siemens Industry Online Support. The general terms of use (http://www.siemens.com/terms_of_use) apply. Security Information Siemens provides products and solutions with industrial security functions that support the secure operation of plants, systems, machines and networks. In order to protect plants, systems, machines and networks against cyber threats, it is necessary to implement and continuously maintain a holistic, state-of-the-art industrial security concept. Siemens products and solutions only form one element of such a concept. The customer is responsible to prevent unauthorized access to its plants, systems, machines and networks. Systems, machines and components should only be connected to the enterprise network or the internet if and to the extent necessary and with appropriate security measures (e.g. use of firewalls and network segmentation) in place. Additionally, Siemens guidance on appropriate security measures should be taken into account. For more information about industrial security, please visit http://www.siemens.com/industrialsecurity. Siemens products and solutions undergo continuous development to make them more secure. Siemens strongly recommends to apply product updates as soon as available and to always use the latest product versions. Use of product versions that are no longer supported, and failure to apply latest updates may increase the customer s exposure to cyber threats. To stay informed about product updates, subscribe to the Siemens Industrial Security RSS Feed under http://www.siemens.com/industrialsecurity. Contents 1 Introduction... 4 2 Installation Notes... 5 2.1 Scope of delivery... 5 2.2 Installation... 5 3 Commissioning... 6 4 Operation and Monitoring from the OS... 7 5 Engineering... 8 5.1 FB1000 "OBSINGLE"... 8 5.2 FB1001 "OBTIME"... 9 5.3 Default Settings of the Runtime Groups... 11 Entry ID: 22000962, V 1.0, 01/2018 2

Entry ID: 22000962, V 1.0, 01/2018 3

1 Introduction 1 Introduction Based on the software calculation of a project with the tool "Protime PCS 7", the cycle of a standard PLC should not be loaded more than 70% so that the system can use free time slices for communication jobs, for example. 70% cycle load means that an S7 program takes 700ms of 1000ms in the PLC, provided that all OB interval times are standardized to 1000ms. For an H system the limit is 60% cycle load, because additional time slices are needed for the redundancy. On the basis of the standard TIME_BEGIN_TIME_END blocks the present block solution reads in the runtimes of the cyclic interrupts OB30 to OB38 and in the PLC calculates the overall cycle load based on the OB interval times set in the HW Config. The block solution is best used during the engineering phase of PCS 7 projects, but can also be implemented for service and maintenance purposes. The tool is the implementation of the Excel table published in the FAQ entitled "Calculation of the AS cycle load caused by OB30 to OB38" http://support.automation.siemens.com/ww/view/en/19688569 Similar tools available in Customer Support: FAQ "Display of the diagnostics buffer contents and the status LED of a CPU/H-CPU running on a PCS 7 / WinCC Operator Station" http://support.automation.siemens.com/ww/view/en/9985721 Expert Communication "Calculator for estimating the memory requirements of typical automation tasks in an S7 CPU (V4.0)" (not specially for PCS 7). Entry ID: 22000962, V 1.0, 01/2018 4

2 Installation Notes 2 Installation Notes 2.1 Scope of delivery The package contains 2 archive files: obinfo_lib.zip : the S7 library with the following objects Function blocks for calculating the OB cycle load in the PLC A hierarchy folder with ready-to-use CFC charts including runtime groups obinfo_lib.zip : OS faceplates and symbols for monitoring the library blocks 2.2 Installation The S7 library and the CFC charts have been created in PCS 7 V6.0 SP3. Use the SIMATIC Manager to unpack the compressed S7 library obinfo_lib.zip in a directory of your choice. As required unpack the obinfo_pdl.zip file in your OS project subdirectory \GRACS. The unpacked obinfo_typicals.pdl file contains the two symbols for copying into an existing standard picture @pcs7_typicals.pdl. Note The blocks contained without the CFC charts can also be used in versions of PCS 7 previous to V6.0 SP3. The CFC charts with interconnections must be created manually. Entry ID: 22000962, V 1.0, 01/2018 5

3 Commissioning 3 Commissioning Note If in the project the TIME_BEG and TIME_END blocks are already being used in CFC charts, it is recommended to delete these instances and then start with Step 1. 1. Open the S7 library with SIMATIC Manager in the Technology View. 2. Open in parallel the project to be measured with SIMATIC Manager in the Technology View. 3. Copy all the CFC charts from the "obinfo" library into the project (into the uppermost TH level, for example). Note When copying the CFC charts, make sure that all the CFC charts are copied in one copying process, because this is the only way for all the CFC charts to be copied automatically into the project along with all the runtime groups. Note If FB1000 or FB1001 are already available, then you have to rename them. More information on the topic of how to merge blocks with the same numbers is available under: https://support.industry.siemens.com/cs/ww/en/view/82525512 4. Check the PLC OS assignments of the new TH folder "obinfo" and change the project policies accordingly. 5. Delete the CFC charts "INF_OB3x" for the unused OBs. 6. Open the CFC chart "INF_OB". 7. In the runtime order, shift the "StartGroupOB3x" group to the beginning and the "EndGroupOB3X" group to the end of the OB concerned. 8. Compile the CFC charts. 9. Delete the empty runtime groups with "Edit > Delete empty runtime groups". 10. Download the CFC charts into the AS. 11. Start the CFC Test mode and monitor the outputs of the block instance "InfoOB". Entry ID: 22000962, V 1.0, 01/2018 6

4 Operation and Monitoring from the OS 4 Operation and Monitoring from the OS Optionally you can also have the OB3x cycle load and the OB3x start information displayed in the OS Runtime. For both function blocks there are faceplates available that are created automatically in the assigned pictures with the function "Create/update block symbols". The requirement for this is execution of the steps described in the chapters entitled Installation and Commissioning. Only the views "Standard" and "Trend" are created in each case. The faceplates have been created with the Faceplate Designer of PCS 7 V6 and can be adapted as required to meet special demands. Faceplate and symbol for FB1000 "OBSINGLE": Faceplate and symbol for FB1001 "OBTIME": Entry ID: 22000962, V 1.0, 01/2018 7

5 Engineering 5 Engineering 5.1 FB1000 "OBSINGLE" Use: Read out the start information of the OB3x using SFC6 "RD_INFO". Run sequence The block FB1000 has to be incorporated after "TIME_END" at the end of the runtime group of each used OB. Input parameters: Runtime of an OB3x in ms, determined with the blocks TIME_BEG and Time_END. Switch for saving the maximum runtime. Output parameter: Number of the OB Runtime of the OB in ms Interval time set Phase shift set Priority of the OB3x set OCM-capable parameters: Input switch "MODE" All output parameters Setup Entry ID: 22000962, V 1.0, 01/2018 8

5 Engineering 5.2 FB1001 "OBTIME" Use: Calculation of the CPU cycle load from the individual OB runtimes with and without correction. Run sequence The point of incorporation in the runtime order is arbitrary, but it is most practical point is in the slowest used OB after the OBtime. Input parameters: Runtime of the OB3x used Cycle intervals of the OB3x used Output parameter: Correction time for the cycle duration of the OB3x used, which can be caused by lower-level, higher-priority OB3x OB3x cycle load without taking into account the correction times OB3x cycle load taking into account the correction times OCM-capable parameters: All output parameters Entry ID: 22000962, V 1.0, 01/2018 9

5 Engineering Setup Entry ID: 22000962, V 1.0, 01/2018 10

5 Engineering 5.3 Default Settings of the Runtime Groups FB "TIME_BEG" is incorporated in a group at the beginning of each OB. FB "TIME_END" and FB1000 are incorporated in a group at the end of each OB. The calculation block FB1001 is incorporated in the OB30 in the runtime group "InfoGroup". Entry ID: 22000962, V 1.0, 01/2018 11