Lumel RE15, User Manual, Page: 3 / 28

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CONTENTS
1. PREFACE ............................................................................... 4
2. DESCRIPTION OF THE MODBUS PROTOCOL .................... 4
2.1. ASCII framing ................................................................. 6
2.2. RTU framing ................................................................... 6
2.3. Characteristic of frame fields ....................................... 7
2.4. LRC checking ................................................................ 9
2.5. CRC checking ................................................................ 9
2.6. Character format in series transmission .................... 10
2.7. Transaction interruption .............................................. 10
3. DESCRIPTION OF FUNCTIONS .......................................... 11
3.1. Readout of N-registers (Code 03) .............................. 11
3.2. Writing of values into the register (Code 06) ............. 12
3.3. Writing into N-registers (Code 16) .............................. 13
3.4. Report identifying the device (Code 17) ..................... 13
4. ERROR CODES .................................................................... 15
5.TABLE OF REGISTERS FOR THE RE15 CONTROLLER ..... 17
AFFIX A. CALCULATION OF THE CHECKSUM .................... 23