DMC, a Siemens Solution Partner with the most S7 Certified Engineers in the United States, presented insights to people new to Siemens to help avoid common mistakes at the 2011 Siemens Automation Summit. Over the years we have encountered numerous applications written by novices and seen first-hand some of the more common errors made.

1. 2011 Automation Summit Orlando, FLNavigating the world of automation

2. Page 2 Top Ten Programming Mistakes Made by People New to S7 2011 Automation Summit Title: Top Ten Programming Mistakes Made by People New to S7 Track:#56 Topic: Learn about some of the common problems experienced by people learning S7. Presenter: Tim Jager Company: DMC

3. Top Ten Programming Mistakes Made by People New to S7 Page 3

4. Company Profile Based In Chicago… …but work Globally DMC has the highest number of S7 certified engineers Since 1996 30 Employees

5. Our customers

6. Areas of Expertise Manufacturing and Automation Intelligence Test and Measurement Custom Software Engineering & Embedded Systems Microsoft SharePoint Consulting Services

8. S7 400H Redundant PLC

10. Standardized code base

11. Deployment at multiple facilities

12. Mixing/batching control

13. Recipe management

15. WinCC Flex HMI’s

16. Standardized code base

17. User Configurable

18. JIT - Lean Manufacturing

21. Top 10 S7 Mistakes #1 Page 12 Simple Hardware mistakes

22. Common Hardware Mistakes Page 13 My PLC Doesn’t Work???

23. Common Hardware Mistakes Page 14 My PLC Doesn’t Work??? It needs a memory card

24. Common Hardware Mistakes Page 15 My PLC Doesn’t Work??? It needs a memory card It’s in STOP Mode

25. Common Hardware Mistakes Page 16 I wonder what’s on the MMC Card?

26. Common Hardware Mistakes Page 17 I wonder what’s on the MMC Card?

27. Common Hardware Mistakes Page 18 I wonder what’s on the MMC Card?

28. Common Hardware Mistakes Page 19

29. Common Hardware Mistakes Page 20 This is not an RS232 Serial Port!!!

30. Top 10 S7 Mistakes #2 Page 21 Using Absolute Address Priority instead of Symbolic

31. Set your Address Priority to Symbolic You Just took the Red pill…. You are on your way down the rabbit hole that leads down the path of true object oriented PLC Programming. Page 22

32. A Typical Data Block DB1 “dbGlobals” Page 23

33. A Typical Data Block DB1 “dbGlobals” Page 24 Symbol Name: “dbGlobals”.bStart Address: DB1.DBX0.0

34. A Typical Rung Of Ladder Page 25

35. A Typical Rung Of Ladder Page 26 Address Logic Symbolic Logic

36. A Typical Rung Of Ladder Page 27 Address Logic Symbolic Logic

37. What happens if we change the Data Block? Page 28

38. Absolute vs. Symbolic Priority Page 29 In Symbolic Mode the intended logic is maintained The address logic has changed from 0.1 to 0.2 The symbolic logic is maintained

39. Absolute vs. Symbolic Priority Page 30 In Absolute Mode the intended logic is NOT maintained! The Address logic is maintained But the Symbolic logic is totally wrong!

40. Absolute vs. Symbolic Priority Page 31 You don’t have to know where the server lives or it’s IP address. You just need the symbolic name to send an email. So start forgetting about addresses and start thinking about symbolic names. VS. Absolute Address 2222N. Elston Ave Chicago, IL 60614 Symbolic Address tim.jager@dmcinfo.com

41. Top 10 S7 Mistakes #3 Page 32 I/O Mapping

42. …I'm gonnaProgram… like it's 1999 Page 33 Input / Output Mapping

43. Traditional Input / Output Mapping Page 34 1. At the beginning of the scan, Each physical input gets mapped to an internal variable… Physical Input Internal Variable

44. Traditional Input / Output Mapping Page 35 1. At the beginning of the scan, Each physical input gets mapped to an internal variable… 2. Now run all of the logic (which references only internal bits)… Internal Variable Internal Variable

45. Traditional Input / Output Mapping Page 36 1. At the beginning of the scan, Each physical input gets mapped to an internal variable… 2. Now run all of the logic (which references only internal bits)… 3. …At the end of the scan, internal “output” bits get mapped to physical outputs Internal Variable Physical Output

46. Page 37 S7 I/O Mapping – Just use the Symbol Table Make sure you are in Symbolic Priority Mode

47. Top 10 S7 Mistakes #4 Page 38 Improper Use of Bit Memory AKA: Mbits

48. MBits M0.0 – M0.7 M1.0 – M1.7 M2.0 – M2.7 M2.0 – M2.7 Page 39

49. MBits MBytes M0.0 – M0.7 MB0 M1.0 – M1.7 MB1 M2.0 – M2.7 MB2 MB3 M2.0 – M2.7 Page 40

50. MBits MBytes MWords M0.0 – M0.7 MB0 MW0 M1.0 – M1.7 MB1 M2.0 – M2.7 MB2 MW1 MB3 M2.0 – M2.7 Page 41

51. MBits MBytes MWords MDoubleWords M0.0 – M0.7 MB0 MW0 M1.0 – M1.7 MB1 MD0 M2.0 – M2.7 MB2 MW1 MB3 M2.0 – M2.7 Page 42

53. Quick prototyping / demonstrations

54. When you absolutely have to!Page 43

56. When is it OK to use M Bits? Page 45 If you use MBits, make sure they are NOT IN USE already.

57. When is it OK to use M Bits? ..and make sure to add symbol names in the symbol table. Page 46

58. When is it OK to use M Bits? Or suffer the consequences…… Page 47

60. Top 10 S7 Mistakes #5 Page 49 Not using or Improperly using the Clock Byte

61. What is the Clock Byte? Page 50 Each bit of the clock memory byte is assigned a frequency.

62. Symbol Table Entry For Clock Byte Page 51 Reserve these so nobody uses Memory overlapping the Clock Byte

63. Clock Byte Page 52 The bits within the Clock byte can change at any time during the scan.

64. Clock Byte – Synchronous Global Page 53 UDT1 “udtClockByte”

65. Clock Byte – Synchronous Global Page 54 DB1 “dbGlobals”

66. Clock Byte – Synchronous Global Page 55 DB1 “dbGlobals”

67. Clock Byte – Synchronous Global Page 56 DB1 “dbGlobals”

68. Clock Byte – Synchronous Global Page 57 MB0 dbGlobals.ClockByte

69. Page 58 What Happens If…… “Always_False” Mapped to M0.0 “Always_True” Mapped to M0.1

70. Page 59 What Happens If…… “Always_False” Mapped to M0.0 “Always_True” Mapped to M0.1 Clock Byte Mapped to MB0

71. Overlapping Mbits are BAD! Page 60

72. Top 10 S7 Mistakes #6 Page 61 Using Uninitialized Temp Memory

73. What is Temp Memory? Page 62

74. Improper Use of Temp Memory Page 63

75. Improper Use of Temp Memory Page 64 Don’t read from a TEMP unless you have written to it first!

76. Top 10 S7 Mistakes #7 Page 65 Not Using Timed Interrupts.

77. OB1 vs. OB30..38 Page 66 OB1 Runs as fast as it can. OB30…OB38 Run at specific time intervals.

78. Timed Interrupts OB30..OB38 Page 67 PID Control Data Sampling

79. Top 10 S7 Mistakes #8 Page 68 Not using reusable function blocks

81. Code is encapsulated in a Highly reusable form

83. Creation of Function Block Isolate Common/Duplicate Code If the same code is used many times in your program, consider creating function blocks.

84. Creation of Function Block Isolate Common/Duplicate Code Step 1. locate common code.

85. Creation of Function Block Isolate Common/Duplicate Code Step 1. locate common code.

86. Creation of Function Block Isolate Common/Duplicate Code Step 2. Replace duplicated code with function blocks.

87. Valve FB Custom FB Examples Motor FB Pump FB Cylinder FB Robot Interface FB Barcode Scanner FB Label Printer FB Machine Vision FB

88. Top 10 S7 Mistakes #9 Page 76 Inconsistent Blocks

89. Check Block Consistency Page 77 Don’t forget to download the Data Block!!

90. Top 10 S7 Mistakes Page 78 And last but not least……..

91. Top 10 S7 Mistakes #10 Page 79 Going it Alone

92. Thank You! Page 80