Lochinvar SYNC SB 1000 User manual

SYNC-MODB Rev A
This manual must only be used by a
qualified heating installer / service
technician. Read all instructions,
including this manual, the
Installation and Operation Manual,
and the Service Manual, before
installing. Perform steps in the
order given. Failure to comply could
result in severe personal injury,
death, or substantial property
damage.
WARNING
Save this manual for future reference.
MODBUS COMMUNICATION
INSTRUCTIONS
SYNC Models: 1.0 - 1.3 - 1.5

2
1 Introduction
The information contained in this manual provides general guidelines for the implementation of Modbus communication with
the Lochinvar SYNC boiler.
All Modbus networks are implemented utilizing a master-slave arrangement where all SYNC boilers are slaves and the master is
a building automation system capable of communicating over a RS-485 serial connection.
Contents
1. INTRODUCTION
Definitions .................................................................... 2
Minimum System Requirements .................................. 2
2. CONFIGURATION
Addressing ................................................................... 3
Timing Specifications ................................................... 4
Parity ............................................................................ 4
Data Transmission Mode ............................................. 4
Modbus Board Diagnostics .......................................... 4
Internal Faults ......................................................... 4
Modbus Function Set.............................................. 5
Modbus Exception Codes ............................................ 6
3. MEMORY MAP
Primary Data Tables.....................................................7
SYNC Boiler Memory Map...........................................7-8
Input Registers .......................................................8
Holding Registers ...................................................8
Configuration Bits.........................................................8
4. WIRING REQUIREMENTS
Physical Wiring.............................................................9
Typical Boiler System Wiring...................................12-13
5. UNIT OPERATION
Unit Operation with Modbus Communications........ 14-17
6. TROUBLESHOOTING ........................................... 18-19
7. DIAGRAMS
Ladder Diagram Part 1 & 2..................................... 20-21
Wiring Diagram............................................................ 22
Revision Notes ................................................... Back Cover
Abbreviation or Acronym Meaning
ASCII American Standard Code for Information Interchange
BAS Building Automation System
Baud (Baud Rate) Number of data bits transmitted per second (bps)
EMS Energy Management System
FDX Full-Duplex
HDX Half-Duplex
Hex Hexadecimal Number (0 - 9, A - F)
I/O Box Input/Output (I/O)
LSB Least Significant Byte
Modbus® A serial, half-duplex data transmission protocol developed by AEG Modicon
MSB Most Significant Byte
RS232 A standard for serial, full-duplex (FDX) transmission of data based on the
RS232 Standard
RS485 A standard for serial transmission of data based on the RS-485 Standard
RTU Remote Terminal Unit
Definitions
Minimum System Requirements
• BAS system or computer with a serial or USB port with a converter to RS-485.
• SYNC boiler equipped with Modbus communication board.
• Shielded twisted pair communication cable.

3
2 Configuration
Addressing
The Modbus addressing space is comprised of 256 different
addresss.
• 0 is reserved for broadcast messages from the master
device
• 1 - 247 are free to use for each unique device
• 248 - 255 are reserved
To set the Modbus address the dip switches can be set in
either the 0 position or the 1 position. For switches set to the
1 position their value will be added together to determine the
address.
For each switch set to the 1 position it has the following value:
Dip switch 1 = 1
Dip switch 2 = 2
Dip switch 3 = 4
Dip switch 4 = 8
Dip switch 5 = 16
Dip switch 6 = 32
Dip switch 7 = 64
Dip switch 8 = 128
Any dip switch set to 0 has a value equal to 0.
Example:
To set the address of the Modbus board to 50, dip switches 2, 5,
and 6 have to be set to the 1 position. The address is determined
by adding the values of all the dip switches together.
Address = Value of Dip switch 1 + Value of Dip switch 2 + Value
of Dip switch 3 + Value of Dip switch 4 + Value of Dip switch 5
+ Value of Dip switch 6 + Value of Dip switch 7 + Value of Dip
switch 8
In this example:
Address = 0 + 2 + 0 + 0 + 16 + 32 + 0 + 0 = 50
Modbus Instructions
The Modbus communication board is equipped with a set of ten dip switches that are used to set the board configuration
(address, baud rate, and parity settings). The first eight are used to set the address of each board. The ninth baud rate. The tenth
is parity.
LED’S
DIP SWITCHES
Figure 2-1_Modbus Communication Board

4
Modbus Instructions
2 Configuration
Timing Specifications
The baud rate for the Modbus board is selectable with Dip
switch #9.
1 = 19200 bps
0 = 9600 bps
Each message is started by at least 3.5 character times of
silence. The maximum delay between frames is 1.5 character
times.
When the system temperature and/or tank temperature is
provided by the BAS to the boiler, it is critical that the
temperature be updated every few seconds. If the boiler does
not receive updated temperatures within a timeout period
(installer adjustable), the control will revert to using its own
sensor inputs (if sensors are connected). The timeout is
programmable by pressing the MAIN>>SETUP>>BMS
buttons. The timeout is adjustable between 5 and 120
seconds. The default timeout is 10 seconds.
When the BAS is not providing either of these temperatures,
but is still controlling the boiler (such as providing a
modulation command), the BAS must refresh these
commands at least every 4 minutes. If the commands are not
refreshed, the boiler will revert to operating based on its own
inputs.
Parity
Parity is set by the position of Dip switch #10.
0 = No Parity
1 = Odd Parity
If No Parity is selected there will be two stop bits, otherwise
there will be one.
Data Transmission Mode
Many Modbus bus master devices can be configured to transmit
data in either Modbus RTU or Modbus ASCII modes. Since
RTU messages can be formatted to use fewer data bits and are
therefore more efficient, RTU has been chosen to be used with
all Lochinvar Modbus communication. Please ensure that the
master device is transmitting Modbus RTU.
Modbus Board Diagnostics
The Modbus board is equipped with three LED’s for visual
diagnostics: Two yellow LED’s and one green. One yellow LED
(D5) is used to indicate reception of data. The other yellow
LED (D6) is used to indicate transmission of data. The green
LED (D7) is used to show internal faults.
Internal Faults:
Normal Operation = 1 second on, 1 second off
Controller Fault = Continuously on
No Burner Control Communication = 0.5 seconds on, 1.5
seconds off
No Modbus Communication = 1.5 seconds on, 0.5 seconds
off
Modbus Communication
The Modbus communication commands and exception codes
that are supported by the Modbus communication board can
be found on pages 5 and 6 of this manual.

5
2 Configuration (continued)
Modbus Instructions
Function Sub Function HEX Description
Dec HEX Dec
1 01 Read Coil Status
2 02 Read Input Status
3 03 Read Holding Registers
4 04 Read Input Registers
5 05 Force Single Coil
6 06 Preset Single Register
7 07 Read Exception Status
8 08 0 00 Diagnostic - Return Query Data
1 01 Diagnostic - Restart Communication
2 02 Diagnostic - Return Diagnostic Register
4 04 Diagnostic - Force Listen Mode
10 0A Diagnostic - Clear Counters and Diagnostic
Registers
11 0B Diagnostic - Return Bus Message Count
12 0C Diagnostic - Bus Communication Error Count
13 0D Diagnostic - Bus Exception Error Count
14 0E Diagnostic - Return Slave Message Count
15 0F Diagnostic - Return Communication Error Count
16 10 Diagnostic - Return Slave NAK Count
17 11 Diagnostic - Return Slave Busy Count
18 12 Diagnostic - Return Bus Character Overrun Count
20 14 Diagnostic - Clear Overrun Counter and Flag
11 0B Get Communication Event Counter
12 0C Get Communication Event Log
15 0F Write Multiple Coils
16 10 Write Multiple Registers
17 11 Report Slave ID
23 17 Read / Write Multiple Registers
Modbus Function Set

6
Modbus Instructions
2 Configuration
MODBUS Exception Codes
Code Name Meaning
01 ILLEGAL FUNCTION
The function code received in the query is not an allowable action for the server
(or slave). This may be because the function code is only applicable to newer
devices, and was not implemented in the unit selected. It could also indicate that
the server (or slave) is in the wrong state to process a request of this type, for
example because it is unconfigured and is being asked to return register values.
02 ILLEGAL DATA ADDRESS
The data address received in the query is not an allowable address for the server
(or slave). More specifically, the combination of reference number and transfer
length is invalid. For a controller with 100 registers, the PDU addresses the first
register as 0, and the last one as 99. If a request is submittted with a starting
register address of 96 and a quantity of registers of 4, then this request will
successfully operate (address-wise at least) on registers 96, 97, 98, 99. If a
request is submitted with a starting register address of 96 and a quantity of
registers of 5, then this request will fail with Exception Code 0x02 “Illegal Data
Address” since it attempts to operate on registers 96, 97, 98, 99 and 100, and
there is no register with address 100.
03 ILLEGAL DATA VALUE
A value contained in the query data field is not an allowable value for server (or
slave). This indicates a fault in the structure of the remainder of a complex
request, such as that the implied length is incorrect. It specifically does NOT
mean that a data item submitted for storage in a register has a value outside the
expectation of the application program, since the MODBUS protocol is unaware of
the significance of any particular value of any particular register.
04 SLAVE DEVICE FAILURE An unrecoverable error occurred while the server (or slave) was attempting to
perform the requested action.
05 ACKNOWLEDGE
Specialized use in conjunction with programming commands. The server (or
slave) has accepted the request and is processing it, but a long duration of time
will be required to do so. This response is returned to prevent a timeout error from
occurring in the client (or master). The client (or master) can next issue a Poll
Program Complete message to determine if processing is completed.
06 SLAVE DEVICE BUSY
Specialized use in conjunction with programming commands. The server (or
slave) is engaged in processing a long -- duration program command. The client
(or master) should re-transmit the message later when the server (or slave) is free.
08 MEMORY PARITY ERROR
Specialized use in conjuction with function codes 20 and 21 and reference type 6,
to indicate that the extended file area failed to pass a consistency check. The
server (or slave) attempted to read record file, but detected a parity error in the
memory. The client (or master) can retry the request, but service may be required
on the server (or slave) device.
0A GATEWAY PATH UNAVAILABLE
Specialized use in conjunction with gateways, indicates that the gateway was
unable to allocate an internal communication path from the input port to the output
port for processing as the request. Usually means that the gateway is
misconfigured or overloaded.
0B GATEWAY TARGET DEVICE
FAILED TO RESPOND
Specialized use in conjunction with gateways, indicates that no response was
obtained from the target device. Usually means that the device is not present on
the network.
Modbus Exception Codes

7
Modbus Instructions
Primary Data Tables
Table Data Type Read / Write
Discrete Inputs Single Bit Read Only
Coils Single Bit Read / Write
Input Registers 16-Bit Word Read Only
Holding Registers 16 Bit Word Read / Write
SYNC Boiler Memory Map
Coils
Address Description Default Unit Min. Max. Resolution
00001 Boiler Enable / Room Thermostat 1 / Stage 1 01=ON / 0=OFF 0 1 1
00005 Tank Thermostat 01=ON / 0=OFF 0 1 1
Discrete Inputs
10001 Manual Reset High Limit 1 01=ON / 0=OFF 0 1 1
10002 Flow Switch 1 01=ON / 0=OFF 0 1 1
10003 Gas Pressure Switch 1 01=ON / 0=OFF 0 1 1
10004 Louver Proving Switch 1 01=ON / 0=OFF 0 1 1
10005 Air Pressure Switch / Flap Valve 1 01=ON / 0=OFF 0 1 1
10006 Blocked Drain Switch 1 01=ON / 0=OFF 0 1 1
10007 Auto Reset High Limit 1 01=ON / 0=OFF 0 1 1
10008 Flame 1 01=ON / 0=OFF 0 1 1
10009 Enable / Room Thermostat 1 / Stage 1 01=ON / 0=OFF 0 1 1
10010 Tank Thermostat 01=ON / 0=OFF 0 1 1
10017 Manual Reset High Limit 2 01=ON / 0=OFF 0 1 1
10018 Flow Switch 2 01=ON / 0=OFF 0 1 1
10019 Gas Pressure Switch 2 01=ON / 0=OFF 0 1 1
10020 Louver Proving Switch 2 01=ON / 0=OFF 0 1 1
10021 Air Pressure Switch / Flap Valve 2 01=ON / 0=OFF 0 1 1
10022 Blocked Drain Switch 2 01=ON / 0=OFF 0 1 1
10023 Flame 2 01=ON / 0=OFF 0 1 1
10033 Run-time Contacts 01=ON / 0=OFF 0 1 1
10034 Alarm Contacts 1 01=ON / 0=OFF 0 1 1
10035 CH Pump 1 01=ON / 0=OFF 0 1 1
10036 DHW Pump 1 01=ON / 0=OFF 0 1 1
10038 Gas Valve 1 01=ON / 0=OFF 0 1 1
10039 System Pump 01=ON / 0=OFF 0 1 1
10041 Run-time Contacts 2 01=ON / 0=OFF 0 1 1
10042 Alarm Contacts 2 01=ON / 0=OFF 0 1 1
10043 CH Pump 2 01=ON / 0=OFF 0 1 1
10046 Gas Valve 2 01=ON / 0=OFF 0 1 1
3 Memory Map

8
Modbus Instructions
Input Registers
Address Description Default Unit Min. Max. Resolution
30001 Discrete Inputs 1 - 16 0 NA 0 65535 1
30002 Discrete Inputs 17 - 32 0 NA 0 65535 1
30003 Discrete Inputs 33 - 48 0 NA 0 65535 1
30004 System / Cascade Setpoint 0Degrees Celsius 0 130 0,5
30006 Cascade Total Power 0 % 100 800 1
30007 Cascade Current Power 0 % 0 800 1
30008 Outlet Setpoint 1 0Degrees Celsius 0 130 0,5
30009 Outlet Temperature 1 0Degrees Celsius 0 130 0,1
30010 Inlet Temperature 1 0Degrees Celsius -20 130 0,1
30011 Flue Temperature 1 0Degrees Celsius -20 130 0,1
30012 Firing Rate 1 0 % 0 100 1
30014 Boiler 1 Status Code 0 NA 0 65535 1
30015 Boiler 1 Blocking Code 0 NA 0 65535 1
30016 Boiler 1 Lockout Code 0 NA 0 65535 1
30017 Outlet Setpoint 2 0Degrees Celsius 0 130 0,5
30018 Outlet Temperature 2 0Degrees Celsius 0 130 0,1
30019 Inlet Temperature 2 0Degrees Celsius -20 130 0,1
30020 Flue Temperature 2 0Degrees Celsius -20 130 0,1
30021 Firing Rate 2 0 % 0 100 1
30023 Boiler 2 Status Code 0 NA 0 65535 1
30024 Boiler 2 Blocking Code 0 NA 0 65535 1
30025 Boiler 2 Lockout Code 0 NA 0 65535 1
Holding Registers
40001 Configuration 0 NA 0 65535 1
40002 Coils 0 NA 0 65535 1
40003 0-10 Volt Input / Rate Command /
Setpoint Command 0 % 0 100 1
40004 Tank Setpoint 0Degrees Celsius 0 87,5 0,5
40005 Tank Temperature 0Degrees Celsius -20 130 0,1
40006 Outdoor Temperature 0Degrees Celsius -40 60 0,1
40007 System Supply Temperature 0Degrees Celsius -20 130 0,1
SYNC Boiler Memory Map
3 Memory Map
Configuration Bits
Address 40001 contains configuration bits sent from the BAS to the boiler. These bits tell the boiler to use its own internal inputs,
or inputs from the BAS. When a bit is set to 1, the boiler will ignore the corresponding value contained internally, and expect the
BAS to write that value into the Holding Registers. The configuration bits are as follows:
Bit 4: System Supply Temperature
Bit 5: Outdoor Temperature
Bit 6: Tank Temperature
Bit 7: System Return Temperature
Bit 8 - 15: Not Used (Default = 0)
Bit 0 (LSB): Boiler Enable
Bit 1: Tank Thermostat
Bit 2: Rate Command / 10 - 10V Input / Setpoint Command
Bit 3: Tank Setpoint

9
Modbus Instructions
4 Wiring Requirements
RS-485 Communication Bus
• Maximum Length = 4000 feet
• Cable Specification = 24 AWG / A,B (twisted pair) and GND Shielded, with characteristic Impedance = 120 ohm
• Maximum Load = 32 units (32 nodes)
NOTE: Cable must be terminated with 120 ohm impedance matching resistor on each end.
Note that when the System Supply Temperature and/or the Tank Temperature are provided by the BAS, they need to be refreshed
every few seconds. This is required in order to prevent unwanted fluctuations in these temperatures. If these values are not
provided every few seconds (timeout is programmable), the boiler will revert to its own internal control. If neither of these
temperatures is provided by the BAS, but any of the other control signals are being provided, the BAS will still need to refresh
these inputs at least every 4 minutes.
Physical Wiring
Figure 4-1_Terminal Strip Connections
1 ALARM
LBL20052 REV B
30 SHIELD GND
MOD BUS
0 - 10V INPUT
2 CONTACTS
3 RUN TIME
4 CONTACTS 5 LOUVER
6 PROVING
8 FLOW SWITCH
10 FLOW SWITCH
29 A
26 SENSOR
25 TANK
24 SENSOR
23 OUT DOOR
22 SENSOR
21 SYSTEM
20 (-)
19 (+)
18 SHIELD GND
17 B
16 A
15 SHIELD GND
14 W
13 R
11 TANK
12 THERMOSTAT
28 B
27 SHIELD GND
CASCADE
ENABLE
A BA
B
A
B
BUILDING
MANAGEMENT
SYSTEM LOUVER
PROVING
SWITCH
TANK
THERMOSTAT
ENABLING DEVICE
SYSTEM SENSOR
OUTDOOR SENSOR TANK SENSOR
SHIELD
SHIELD
FROM PREVIOUS BOILER TO NEXT BOILER
SHIELD
HEAT EXCHANGER 2 FLOW SWITCH
HEAT EXCHANGER 1 FLOW SWITCH
A
B
SHIELD
MODBUS COMMUNICATION BUS
TO NEXT BOILER
9 HEX 1
7 HEX 2

10
4 Wiring Requirements
Figure 4-2_Control Inputs
GAS PRESSURE SWITCH
ROOM THERMOSTAT /
ZONE CONTROL
FLOW SWITCH
SYSTEM SENSOR
OUTDOOR SENSOR
SEQUENCER / BUILDING
MANAGEMENT SYSTEM
LOW VOLTAGE
CONNECTION
BOARD
HEAT EXCHANGER 1 /
HEAT EXCHANGER 2 INLET
TEMPERATURE SENSOR
HEAT EXCHANGER 1 /
HEAT EXCHANGER 2 OUTLET
TEMPERATURE SENSOR
HEAT EXCHANGER 1 /
HEAT EXCHANGER 2 FLUE GAS SENSOR
HEAT EXCHANGER 1 /
HEAT EXCHANGER 2 HIGH LIMIT SENSOR
FLAME SENSOR
LOW WATER CUTOFF
BLOCKED DRAIN SWITCH
TOUCH PANEL
INTERFACE
PC INTERFACE
SECONDARY
SMART TOUCH
CONTROL MODULE
PRIMARY
SMART TOUCH
CONTROL MODULE
HW TANK SENSOR
HW THERMOSTAT
TOUCH DISPLAY
MODBUS COMMUNICATION
BOARD
Modbus Instructions