The CMS Pixel PLC Code1 CMS Pixel PLC Code Review - Closing Session - Christian Veelken UC Davis 06/26/08

The CMS Pixel PLC Code2 The revised Pixel PLC Code Changes to Pixel PLC Code resulting from Review: Changes in Functionality Coding Improvements Improvements to Hardware Configuration Lifetime of Relays Configuration Parameter Checks Open Issues

The CMS Pixel PLC Code3 Changes in Functionality Implemented Diagnostic Interrupt Organization Blocks OB 80, OB 81, … OB 88 OB 121, OB 122 Stefan Lueders Piero Girgio Verdini Added Data-Block for Log-Messages; filled with Entries whenever one of the Diagnostic OBs gets called Adapted from Example Code provided by Stefan Lueders

The CMS Pixel PLC Code4 Coding Improvements - 1 Reduced number of Function Blocks –FC 1110 “isEven” replaced by “MOD 2” –merged FC 1400 and FC 1401 –merged FC 1411 and FC 1412 –removed FC 1421 “testBit” Jim Kowalkowski Kevin Krause Stefan Lueders Replaced all Instances of “Time_of_Day” by “Date_and_Time” Variables; “Date_and_Time” now consistently used everywhere in the Code Jim Kowalkowski FC 1240 “syncSystemDate_and_Time” removed; replaced by Timer Server Stefan Lueders Piero Girgio Verdini

The CMS Pixel PLC Code5 Coding Improvements - 2 Return codes of SFC 20 “BLKMOV” and SFC 21 “FILL” taken into account everywhere in the Code Jim Kowalkowski Kevin Krause Stefan Lueders Piero Girgio Verdini Changed Order by which Functions are compiled in Makefile, taking into account Dependencies Stefan Lueders Shortened Variable Names  No Warnings during Compilation anymore Stefan Lueders Piero Girgio Verdini

The CMS Pixel PLC Code6 Coding Improvements - 3 Added Checks for lower Alarm Threshold < upper Alarm Threshold to FC 110 and FC 111 Stefan Lueders Piero Girgio Verdini Changed Heart-Beat Period from 1.6s to 2min  will come back to this later… Other (minor) Code Improvements (Details of which sent to respective Reviewer) Stefan Lueders Piero Girgio Verdini

The CMS Pixel PLC Code7 Improvements to the HW-Config. Added IP Address Protection Added Password Protection for read/write Access to PLC via Siemens Step7 software Enabled Diagnostic Interrupts Stefan Lueders Piero Girgio Verdini

The CMS Pixel PLC Code8 Lifetime of Relays Relay specified for 1 million Switching 0.5 A, 24V DC actually lower Limit, as current significantly smaller in Pixel case  Relay might break after 2-3 weeks of operation in case Heart- Beat Signal has Period of 1.6s.  Change Heart-Beat period to 2 minutes  Lifetime Expectancy for Relay increased to 3-4 years minimum. Stefan Lueders Piero Girgio Verdini

The CMS Pixel PLC Code9 Configuration Parameter Checks - 1 The Change would not reduce the overall Amount of Code (just move it from the PLC to PVSS, where it will not be significantly easier to maintain, we believe). The PLC code would become simpler, but at the same Time the PVSS code would become more complex. Stefan Lueders suggested to move the Implementation of Validity Checks performed on the Configuration Parameters uploaded by PVSS from the Pixel PLC Code to PVSS:  Decided not to to it Reasons:

The CMS Pixel PLC Code10 Configuration Parameter Checks - 2 We do actually prefer to perform the Checks in the PLC, so that the entire Chain of Data Transmission can be validated (Concerns about possible Data Corruption by the PVSS native S7 Driver have been raised by Piero Giorgio Verdini) The current Implementation of the Configuration Parameters in the Pixel PLC Code has been tested, debugged and verified to work. The effort to move the Code for the Configuration Parameter Checks from Pixel PLC code to PVSS and repeat the Testing, Debugging and Verification of the Code would be significant.

The CMS Pixel PLC Code11 Open Issues - 1 CRC-16 Checksums Different Opinions held by different Reviewers: Stefan Lueders “I believe this is Overkill” Piero Giorgio Verdini “PVSS data transmission - strange things to happen from Time to Time. Packets need to be broken up on large Transmissions. Sometimes blocks are garbled.” (Minutes of Meeting 04/25/08)

The CMS Pixel PLC Code12 Unit Tests/automated Code Validation All Reviewers pointed out that this would be good to have, but: suitable Tools are lacking !! Open Issues - 2 Gennadiy Lukhanin “It may be useful to store Checksums for DB 1xx in a Data-Base, so that the entire Chain of Data Transmission from the Data-Base to Data-Blocks in the PLC can be validated.”  Common Issue of CMS Pixel and Silicon Strip Tracker PLC Codes  Issue common to PLC Codes of many (if not all) CMS Subdetectors

The CMS Pixel PLC Code13 Thank you !!

The CMS Pixel PLC Code14 Special Acknowledgements Piero Giorgio Verdini for taking the Time to discuss his Comments with me Stefan Lueders for providing me with an example Implementation of the diagnostic Interrupt Organization Blocks and for taking the Time for many useful Explanations