HTP 7350P-629 - Manual (Page 19)

19
DECIMAL HEX
65286 FF06
Table 21
Outlet temperature from appliance sensor = 155
o
F. 155
o
F X 10 = 1550.
DECIMAL HEX
1550 60E
Table 22
G. APPLIANCE STATUS CODES
The appliance displays an appliance state code on the building screen to help aid in troubleshooting. The appliance state indicates
what the appliance is actually doing. This state should be compared to the command issued and what is expected. If the appliance
state does not agree with the command, check communication and configuration.
STATUS CODES (INPUT REGISTERS 30014 AND 30023)
NUMBER DEFINITION
0 standby
96 Running
100 DHW mode or blocking for Cascade
101 Low Water blocking
Table 23
PART 8 - TROUBLESHOOTING
Should you encounter problems communicating over Modbus, the following items should be checked in this order.
1. Physical layer
2. Communications configuration and port settings
3. Modbus error codes
4. Appliance status / blocking / lockout codes
A. PHYSICAL LAYER
1. Verify the correct Modbus communication cable (twisted pair) is being used.
2. Check that all components have power (appliance, Modbus adapter, gateway, BAS master).
3. Check for broken wires.
4. Check A, B terminal connections.
5. Check for terminating resistors (120 ohms) at each end of the RS-485 bus only.
6. Check all wire lengths. Are any drops too long?
7. Check proper shield grounding.
B. COMMUNICATIONS
1. Verify controller is configured for MODBUS (AUTO or ON)
2. Check baud rate (9600, 19200).
3. Check parity.
4. Check Modbus address.
5. Check port setting on master, gateway, and computers.
6. Check the status of the LEDs, referring to the LED Diagnostics section below.
C. LED DIAGNOSTICS
There are two yellow LED’s and one green LED on the board that provide diagnostic information.
One of the yellow LED’s (D6) is used for indicating reception of data from Modbus and the other LED (D5) indicates transmission of
data to Modbus.
The green LED (D7) is used to show the following:
Internal Faults
Modbus Adapter fault: Continuously Bright
General Faults
No MODBUS (RS-485) communication: 1.5 second bright - 0.5 second off
No Burner Control (RS-232) communication: 0.5 second bright - 1.5 seconds off
In case both communication modes fail the LED will not be lit No Faults
Normal running: 1 second Bright and 1 second Dim
D. MODBUS ERROR CODES
1. Check Modbus communication error codes (see in Part 5, Section E in this manual for Modbus exception codes).