HTP 7350P-629 - Manual (Page 3)

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C. BAUD RATE ............................................................................................................................................................................... 9
D. PARITY AND STOP BITS .......................................................................................................................................................... 9
PART 5 – GENERAL MODBUS INFORMATION ........................................................................................................................ 9
A. DATA TRANSMISSION MODE .................................................................................................................................................. 9
B. MODBUS BOARD DIAGNOSTICS............................................................................................................................................. 9
C. MODBUS COMMUNICATION .................................................................................................................................................. 10
D. MODBUS FUNCTION SET ...................................................................................................................................................... 10
E. MODBUS EXCEPTION CODES .............................................................................................................................................. 11
PART 6 - REGISTER MAP ........................................................................................................................................................ 11
A. PRIMARY DATA TABLES ........................................................................................................................................................ 11
B. APPLIANCE MEMORY MAP .................................................................................................................................................... 11
C. BLOCKING CODES ................................................................................................................................................................. 13
D. LOCKOUT CODES .................................................................................................................................................................. 14
E. STATUS CODES ...................................................................................................................................................................... 14
F. CONFIGURATION BITS ........................................................................................................................................................... 14
PART 7 - APPLIANCE OPERATION......................................................................................................................................... 15
A. APPLIANCE OPERATION WITH MODBUS COMMUNICATIONS .......................................................................................... 15
B. EXAMPLE #1 ............................................................................................................................................................................ 15
C. EXAMPLE #2 ........................................................................................................................................................................... 15
1. SEND FIRING RATE COMMAND FROM MASTER .................................................................................................................... 15
2. SEND TEMPERATURE COMMAND FROM MASTER ................................................................................................................ 16
D. EXAMPLE #3 – HOT WATER GENERATION ......................................................................................................................... 16
E. CASCADE ................................................................................................................................................................................ 16
F. RATE AND TEMPERATURE CONVERSIONS ........................................................................................................................ 17
G. APPLIANCE STATUS CODES ................................................................................................................................................ 19
PART 8 - TROUBLESHOOTING ............................................................................................................................................... 19
A. PHYSICAL LAYER ................................................................................................................................................................... 19
B. COMMUNICATIONS ................................................................................................................................................................ 19
C. LED DIAGNOSTICS ................................................................................................................................................................. 19
D. MODBUS ERROR CODES ...................................................................................................................................................... 19
INSTALLATION AND MAINTENANCE NOTES .............................................................................................................................. 20
HTP CUSTOMER INSTALLATION RECORD FORM...................................................................................................................... 21
PART 1 - GENERAL INFORMATION
Modbus communication systems utilize a master-follower format where connected HTP appliances follow commands from a building
management system or other Modbus master device linked over an RS-485 serial connection.
If any system component(s) is/are exposed to the following, do not operate until the affected component(s) has/have been inspected by
a qualified serviceman.
1. FIRE
2. DAMAGE
3. SUBMERSION IN WATER