MODBUS INSTALLATION TROUBLESHOOTING MOD BUS Models 7350P-629 FOR USE WITH MODCON, MODCON VWH, PIONEER, VERSA-FLAME MANUFACTURED ON OR AFTER JULY 1, 2011 FOR USE WITH ELITE, ELITE VWH MANUFACTURED ON OR AFTER AUGUST 1, 2011 NOTICE: HTP reserves the right to make product changes or updates without notice and will not be held liable for typographical errors in literature. NOTE TO CONSUMER: PLEASE KEEP ALL INSTRUCTIONS FOR FUTURE REFERENCE. 120 Braley Rd. P.O. Box 429 East Freetown, MA 02717-0429 www.
The following defined terms are used throughout this manual to bring attention to the presence of hazards of various risk levels or to important information concerning the product. DANGER indicates an imminently hazardous situation which, if not avoided, will result in death or serious injury. WARNING indicates a potentially hazardous situation which, if not avoided, could result in death or serious injury.
C. BAUD RATE ............................................................................................................................................................................... 9 D. PARITY AND STOP BITS .......................................................................................................................................................... 9 PART 5 – GENERAL MODBUS INFORMATION ......................................................................................................
Any claims for damage or shortage in shipment must be filed immediately against the transportation company by the consignee. A. WHAT’S IN THE BOX 1. 2. 3. One MODBUS Adapter One bag of mounting hardware One mounting template B. MINIMUM SYSTEM REQUIREMENTS 1. A Modbus master device, such as a Building Automation System (BAS) or computer with Modbus master software, and an RS-485 serial port or USB port with a converter to RS-485. 2.
Modbus MSB RS232 RS485 RTU PG MB Table 1 – Acronym definitions A serial, half-duplex transmission protocol developed by AEG Modicon Most Significant Byte RS232 serial, full-duplex (FDX) transmission of data standard RS-485 serial transmission of data standard Remote Terminal Unit Industry Standard liquid-tight wiring entry connector MODBUS PART 2 - INSTALLATION The Modbus adapter should be mounted to a solid surface.
BMS G A B X5 X5 X5 MODBUS ADAPTER APPLIANCE 1 APPLIANCE X REMOVE JUMPER (J1) FROM THIS ADAPTER ONLY! Figure 2 – Jumper Configurations in a Modbus Network B. JUMPER SETTING The appliance display handles most of the Modbus adapter configuration. There is one jumper on the Modbus adapter. When this jumper is in place (factory default) it connects a termination resistor across the data lines of the RS-485 connection. Leave the jumper in if the Modbus adapter is at the end of the RS-485 bus.
PART 3 – COMMUNICATION CONFIGURATION (APPLIANCES WITH A 3 CHARACTER RED LED DISPLAY) A. MODBUS ENABLE 1. Press and hold ENTER and RESET simultaneously. Use the UP and DOWN arrows to show 925 on the display, then press and hold ENTER to enter the installer menu. 2. Once in the Installer Menu, use the ENTER button to navigate to Parameter 37.
D. PARITY AND STOP BITS The parity/stop bits parameter of the Modbus adapter must be set to match the rest of the devices on the bus. Although it is common to set serial devices to use no parity, setting the parity to even or odd may improve communications reliability on all connected devices on the bus. This parameter has 4 possible selections which should be sufficient to establish communication with other devices. These selections are outlined in Table 4.
blinking). Press the RIGHT button to advance to Parameter 39 - Baud Rate. C. BAUD RATE The baud rate (communication speed) can be set to either 9600 or 19200 baud. All HTP appliances, as well as any other device on the same bus and the Modbus master, must have the same baud rate setting. Select the highest baud rate that offers the most reliable communication performance over the bus.
Figure 4 – Modbus Diagnostic LEDs C. MODBUS COMMUNICATION The Modbus communication commands can be found in Parts 3 and 4 of this manual, and exception codes supported by the communication board can be found in Part 5, Section E. D.
FUNCTION DEC SUB FUNCTION HEX DEC 17 18 20 11 12 14 HEX DESCRIPTION Diagnostic – Return follower busy count Diagnostic – Return bus character overrun count Diagnostic – Clear overrun counter and flag Get communication event counter Get communication event log Write multiple coils Write multiple registers Report follower ID Mask write register Write multiple registers Read FIFO Queue 11 0B 12 0C 15 0F 16 10 17 11 22 23 17 24 Table 7 – Modbus function set E.
ADDRESS 10001 10002 10003 10004 10005 10006 10007 10008 10009 10010 10011 10033 10034 10035 10036 10038 10039 10049 10050 10051 10052 10053 10054 10055 10056 10057 10058 10059 10060 10061 10062 10063 10064 10065 30001 30002 30003 30004 30005 30006 30007 30008 30009 30010 30011 30012 30013 30014 30015 30016 30017 DESCRIPTION Manual reset high limit 1 Flow switch 1 Gas pressure switch 1 Louver switch 1 (NOT USED) Air pressure switch / flap valve Blocked drain switch Auto reset high limit 1 Flame 1 Enable
ADDRESS 30018 30019 30020 30021 30022 30023 30024 30025 30026 30027 30028 30029 30030 30031 30032 30033 30034 30035 30036 30037 30038 30039 30040 30041 30042 30043 30044 30045 30046 30047 30048 30049 30050 30051 30052 30053 30054 30055 DESCRIPTION Outlet temp 1 Inlet temp 1 Flue temp 1 Firing rate 1 / Appliance 1 pump speed / Pump 4 OUTPUT Appliance 1 status code Appliance 1 blocking code Appliance 1 lockout code Appliance 2 outlet temperature Appliance 2 firing rate Appliance 2 status Appliance 2 locko
NUMBER 12 13 14 16 17 21 23 25 26 30 31 32 33 Table 11 DEFINITION S1 temperature high S2 temperature high Flue temperature high Regulation temperature high Not enough water flow Anti-cycling CH max flue pressure switch/ max start cycles Max temperature increase limiting CH 24 V to low Water level low 1 Water level high 1 Water level low 2 Water level high 2 D.
HOLDING REGISTER 40001 DEFINITION B0 B1 B2 B3 B4 B5 B6 B7 B8 B9 Boiler enable Tank enable Rate command / 0 – 10V input / set point command (40003) DHW set point (40004) DHW temperature (40005) Outdoor temperature (40006) System supply temperature (40007) System return temperature (40008) I4 offset (40009) CH post purge (40010) HOLDING REGISTER 40001 DEFINITION B10 DHW post purge (40011) B11 Pump 4 speed (40012) B12 Pump 5 speed (40013) B13 Extra 0 – 10 V output (40014) HOLDING REGISTER 40002 DEFINI
HOLDING REGISTERS 40001 40003 Table 16 DEFINITION Configuration Rate Command VALUE 00 04 00 00 ACTION Set configuration to read 40003 Sets modulation % Register 40003 needs to receive the rate command as follows: Acceptable rang is 0 to 100. Value needs to be greater than 15 for the boiler to fire. When the command is 16, the boiler will run at minimum fan speed (firing rate). When the command is 100 the boiler will run at max fan speed (firing rate).
Please note that with Modbus communication connected only to the master appliance, only total cascade information can be seen through the communications link. Information from the follower boilers is limited to follower appliance rate command, supply temperature, fault code, and fault status. If you want to see complete data from each follower, or use the Modbus master to control cascading of multiple appliances, each appliance will need a Modbus communication board.
The table below lists temperature to hexadecimal conversions.
DECIMAL 65286 HEX FF06 Table 21 o o Outlet temperature from appliance sensor = 155 F. 155 F X 10 = 1550. DECIMAL 1550 Table 22 HEX 60E 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.
2. Check Follower ID. 3. Check Modbus command. 4. Check configuration bits for holding register 40001. 5. Check commands and data for holding registers 40002 – 40007.
HTP CUSTOMER INSTALLATION RECORD FORM The following form should be completed by the installer for you to keep as a record of the installation in case of a warranty claim. After reading the important notes at the bottom of the page, please also sign this document.
