HTP 7350P-629 Installation Manual Download

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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