Owner's manual
Table Of Contents
- Table of Contents
- Introduction
- SeaI/O Hardware Description
- SeaI/O Base and Expansion Modules
- SeaI/O Module Common Features
- SeaI/O Configurations & Specifications
- 410 Series – 16 Optically Isolated Inputs/16 Reed Relay Outputs
- 420 Series – 16 Optically Isolated Inputs/8 Form C Outputs
- 430 Series – 32 Optically Isolated Inputs
- 440 Series – 32 Reed Relay Outputs
- 450 Series – 16 Form C Relay Outputs
- 462 Series – 96 Channel TTL DB-78
- 463 Series – 96 Channel TTL 50-Pin
- 470 Series – 16 A/D, 2 D/A, 8 24V Outputs, 8 Isolated Inputs
- 520 Series – 8 Optically Isolated Inputs/8 High-Current Form C Outputs
- Power Options
- Hardware Configuration
- Wiring Options
- Mounting Options
- Accessories
- SeaMAX Application Suite
- SeaI/O Architecture
- Device Address Configuration
- Configuring the “Base” SeaI/O Module
- Configuring N-Series Expansion Modules
- Configuring an Ethernet Module (E-Series)
- MaxSSD Configuration & Diagnostics Utility
- Communicating Via Modbus
- Extended Modbus Command Set
- Developing Custom Applications Using SeaMAX API
- SeaMAX API
- Non Object-Oriented SeaMAX API
- IOCTL Calls and Functionality
- Using SeaMAX with Visual C++ 6.0
- Using SeaMAX with Visual Basic 6.0
- Example SeaMAX Programming Tasks
- CEthernet API
- Appendix A – Data Encoding Tables
- Appendix B – CRC Calculation
- Appendix C – SeaIO Model 462/463 Holding Register Set
- Appendix D – SeaMAX Data Types and Structures
- Appendix E – Troubleshooting
- Appendix F – How To Get Assistance
- Appendix G – Compliance Notices
- Warranty
© Sealevel Systems, Inc.
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SeaI/O User Manual
Appendix B – CRC Calculation
To further illustrate the example shown in the CRC-16 section, the algorithm for
generating the CRC-16 is shown below.
unsigned short calc_crc(int n,unsigned char *outbound_message)
{
unsigned char carry_flag;
unsigned short crc=0xFFFF;
for (int i = 0; i < n; i++)
{
crc = crc ^ outbound_message[i];
for (int j = 0; j < 8; j++)
{
carry_flag = crc & 0x01;
crc = crc >> 1;
if (carry_flag == 1)
{
crc = crc ^ 0xA001;
}
}
}
return crc;
}