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

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CHAPTER 4: USING THE IEEE 1394-BASED PROTOCOL To read a bank of points, see the memory map area “Digital Bank Read—Read Only” on page 119. The starting address for reading counter data is FFFFF0400100. For help in interpreting this data, see “Mask Data” on page 41. To read and clear counters for individual points, see the memory map area “Digital Read and Clear—Read Only” on page 132. If you are reading and clearing the counter at point 0, for example, you would use the starting address FFFFF0F00000. Quadrature Counters I/O units with the following brains also support quadrature counters for quadrature encoder devices: SNAP-UP1-ADS SNAP-B3000-ENET See page 21 for detailed information on using quadrature counters. Watchdog Using a watchdog involves three steps: 1. Setting up the watchdog time in milliseconds 2. Configuring the watchdog values for the critical digital and analog points 3. Enabling the watchdog for those points. SNAP-ENET-RTC SNAP-WLAN-FH-ADS Set up the watchdog time by using the “Status Area Write—Read/Write” on page 107. Write the watchdog time in milliseconds starting at the address FFFFF0380010. This is the amount of time the brain will wait for communication from the host device. Configure the watchdog values for critical digital and analog points using the memory map area “Analog and Digital Point Configuration Information—Read/Write” on page 125. These are points you want to set to a certain state or value if the watchdog timeout occurs. For example, to close a valve at digital output point 1, you would write a zero starting at the address FFFFF0C00064. To set a value on analog output point 4, you would write the EU float starting at the address FFFFF0C00184. Enable the watchdog for the points for which you’ve set watchdog values, also using “Analog and Digital Point Configuration Information—Read/Write” on page 125. For the example of the digital output at point 1, you would write starting with the address FFFFF0C00068. For the analog output at point 4, the starting address would be FFFFF0C00188. 90 SNAP Ethernet-Based I/O Units Protocols and Programming Guide
Scaling CHAPTER 4: USING THE IEEE 1394-BASED PROTOCOL Scaling applies to analog points only. To scale a point, see the memory map area “Analog and Digital Point Configuration Information—Read/Write” on page 125. Write to the point’s addresses for high scale and for low scale. For example, to scale point 2, you would write the high-scale float starting at the address FFFFF0C00094 and the low-scale float starting at FFFFF0C00098. Minimum and Maximum Values SNAP Ethernet-based I/O units with analog capability automatically keep track of minimum and maximum values on analog points. You can read the values at any time, for example, to record minimum and maximum temperatures. You can: Read min/max values for individual points Read a bank of points Read and restart min/max values for individual points. To read min/max values for individual points, see the memory map area “Analog Point Read—Read Only” on page 123, and use the Min Value or Max Value starting address for the point you want to read. For example, you would read the minimum value for point 2 starting at address FFFFF0A00088. To read min/max values for a bank of points, see the memory map area “Analog Bank Read—Read Only” on page 120. The starting address for reading minimum values is FFFFF0600200. For help in interpreting this data, see “IEEE Float Data” on page 43. To read and restart min/max values for individual points, see the memory map area “Analog Read and Clear/Restart—Read Only” on page 133. For example, if you want to record the maximum temperature at point 0 in each 24-hour period, the values must be reset when they are read each day. You would read and restart the maximum value for point 0 using the starting address FFFFF0F80100. Offset/Gain Offset and gain apply to analog input points only. To have the brain calculate offset and gain, use the memory map area “Analog Point Calculation and Set—Read Only” on page 131. Calculate offset first, then calculate gain. For example, calculate offset for point 1 by reading addresses FFFFF0E00004 through FFFFF0E00007. Calculations are completed in the background, and the response gives the offset in counts. Next, calculate gain for point 1 by reading addresses FFFFF0E00104 through FFFFF0E00107. Response for gain is in percent. Since the purpose of the read request is simply to have the offset or gain calculated so that values you read later will be accurate, you can normally ignore the response data. SNAP Ethernet-Based I/O Units Protocols and Programming Guide 91
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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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Streaming Data CHAPTER 2: OVERVIEW
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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 and 94: Bytes 0-3 Bytes 4-7 Bytes 8-11 Byte
Page 95 and 96: Bytes 0-3 Bytes 4-7 Bytes 8-11 The
Page 97 and 98: Bytes 0-3 Bytes 4-7 Bytes 8-11 Byte
Page 99: Read and clear latches for individu
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
Page 149 and 150: Serial Event Configuration—Read/W
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Starting Address Length Type Descri
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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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