snap ethernet-based i/o units protocols and programming guide

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Bytes 0–3 Bytes 4–7 Bytes 8–11 CHAPTER 4: USING THE IEEE 1394-BASED PROTOCOL Write Response Packet (Brain➞PC) When the brain receives the Powerup Clear, it sends a Write Response packet back to the host PC acknowledging receipt. In binary notation, the response packet looks like this: The rcode parameter contains the ACK or NAK for the transaction. The 0 in this example indicates an ACK. In hex, the packet looks like this: 000004200000000000000000. The 0 shown in bold type is the ACK in the rcode. See “Error Codes” on page 98 for information on what to do if you receive a NAK. Configuring destination_ID tl rt tcode pri 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 source_ID rcode reserved 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 reserved 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 SNAP Ethernet-based brains can recognize the presence and type of an analog module on the rack, but the values for each of the points must be configured if they do not match the default for that module type. For example, the brain can report that a SNAP-AITM module is in position 4, but if the points are anything other than the default value of ±150 mV, you must configure them by writing configuration codes to the points. Module types and default values are shown on page 18. Digital modules and empty positions are reported the same by the brain: they are assumed to be digital input modules. If a position contains a digital output module, you must configure the points as outputs. Configuring I/O Point Types—Write Quadlet Request Packet (PC➞Brain) Suppose you have a digital output module in position 0 on the rack. Since the brain cannot distinguish a digital module from an empty position, you need to configure the module’s four output points (points 0–3) as outputs. You configure them by writing to each one’s Point Type address in the “Analog and Digital Point Configuration Information—Read/Write” area of the memory map. On page 125 you can see this area of the map. 84 SNAP Ethernet-Based I/O Units Protocols and Programming Guide
Bytes 0–3 Bytes 4–7 Bytes 8–11 The Write Quadlet Request for point 0 would look like this: CHAPTER 4: USING THE IEEE 1394-BASED PROTOCOL Write Quadlet Request for point 1 (hex): 000004000000FFFFF0C0004400000180 Write Quadlet Request for point 2 (hex): 000004000000FFFFF0C0008400000180 Write Quadlet Request for point 3 (hex): 000004000000FFFFF0C000C400000180 As you can see, the only difference in these packets is the memory map address for the point. For more information on module types and setting point types, see “Configuring I/O Points, Event/Reactions, and Security” on page 92. Configuring I/O Point Types—Write Response Packet (Brain➞PC) The response from the brain is a simple acknowledgment, as you saw before, with the ACK or NAK appearing in the rcode parameter: destination_ID tl rt tcode pri 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 source_ID rcode reserved 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 reserved 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Reading and Writing Memory map address for point 0’s point type Point type designation for digital output Now that the PC has successfully connected to the brain, sent a Powerup Clear, and configured I/O points as necessary, you can read and write to the points. SNAP Ethernet-Based I/O Units Protocols and Programming Guide 85
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SNAP ETHERNET-BASED I/O UNITS PROTO
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Table of Contents Chapter 1: Introd
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Non-velocity Algorithms............
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Disconnecting......................
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Data Logging Configuration—Read/W
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Chapter 1 Introduction CHAPTER 1 We
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About this Guide CHAPTER 1: INTRODU
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For Help CHAPTER 1: INTRODUCTION If
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FEATURE CHAPTER 1: INTRODUCTION Ema
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CHAPTER 1: INTRODUCTION This task C
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CHAPTER 2 Chapter 2 Overview of Pro
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Referencing SNAP I/O Points CHAPTER
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Analog and Digital Systems (N Brain
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Digital-Only Systems The following
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I/O Point Types CHAPTER 2: OVERVIEW
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CHAPTER 2: OVERVIEW OF PROGRAMMING
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Watchdog (Digital and Analog Points
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Page 43 and 44: CHAPTER 2: OVERVIEW OF PROGRAMMING
Page 45 and 46: Streaming Data CHAPTER 2: OVERVIEW
Page 47 and 48: Logging Data Area Number of Bytes I
Page 49 and 50: Using PID Loops What is a PID? CHAP
Page 51 and 52: Equations Common to All Algorithms
Page 53 and 54: CHAPTER 2: OVERVIEW OF PROGRAMMING
Page 55 and 56: CHAPTER 3 Chapter 3 Using the SNAP
Page 57 and 58: CHAPTER 3: USING THE SNAP ETHERNET
Page 63 and 64: Environment Visual Basic 6 Internet
Page 65 and 66: MemMap Example Code CHAPTER 3: USIN
Page 71 and 72: Return Values CHAPTER 3: USING THE
Page 73 and 74: IsOpenDone V Close V Return Values
Page 75 and 76: Digital Point Methods CHAPTER 3: US
Page 77 and 78: SetDigBankOnMask V [in] long nPts63
Page 79 and 80: Analog Bank Methods CHAPTER 3: USIN
Page 81 and 82: GetStatusWatchdogTime [out] long pn
Page 87 and 88: GetLastStreamStandardBlock (ActiveX
Page 89 and 90: CHAPTER 4 Chapter 4 Using the IEEE
Page 91 and 92: CHAPTER 4: USING THE IEEE 1394-BASE
Page 93: Bytes 0-3 Bytes 4-7 Bytes 8-11 Byte
Page 97 and 98: Bytes 0-3 Bytes 4-7 Bytes 8-11 Byte
Page 99 and 100: Read and clear latches for individu
Page 101 and 102: Scaling CHAPTER 4: USING THE IEEE 1
Page 103 and 104: Read and Write Packet Structure Par
Page 109 and 110: CHAPTER 5 Chapter 5 Advanced Modbus
Page 111 and 112: CHAPTER 5: ADVANCED MODBUS PROGRAMM
Page 113 and 114: APPENDIX A Appendix A SNAP Ethernet
Page 115 and 116: Status Area Read—Read Only This i
Page 117 and 118: Date and Time Configuration—Read/
Page 119 and 120: Security Configuration—Read/Write
Page 121 and 122: Serial Module Configuration—Read/
Page 123 and 124: Wiegand Serial Module Configuration
Page 125 and 126: SNMP Configuration—Read/Write (Do
Page 127 and 128: Starting Address Length Type Descri
Page 131 and 132: Digital Point Read—Read Only NOTE
Page 133 and 134: Analog Point Read—Read Only See
Page 135 and 136: Analog and Digital Point Configurat
Page 137 and 138: Digital Events and Reactions—Read
Page 141 and 142: Analog Point Calculation and Set—
Page 143 and 144: Analog Read and Clear/Restart—Rea
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Starting Address Length Type Descri
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Serial Event Configuration—Read/W
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Data Log—Read/Write (Does not app
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Appendix B Table of Offsets Introdu
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Module Point (Decimal) Point (Hex)
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Index A access, setting up SNMP sec
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error codes IEEE 1394-based protoco
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O off-latch, 20 offset, 24 IEEE 139
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