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Control System (ACS)
User Manual
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AERCO Control System (ACS) User Manual

GF-131
AERCO Control System (ACS)
OMM-0081_0D
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, New York 10913 • Phone: 800-526-0288
High Efficiency Innovation
AERCO Control System
(ACS)
USER MANUAL
AERCO Control System (ACS) Front Panel
Revised: 04/23/2013
Used for up to Thirty-two (32)
• Benchmark Series Boilers
Installation, Operation, and Maintenance
AERCO Boilers including:
• AERCO Modulex Series Boilers
• AERCO KC-1000 Series Boilers
MC2: 04/23/13 Page 1 of 144
GF-131
AERCO Control System (ACS)
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, New York 10913 • Phone: 800-526-0288
OMM-0081_0D
Technical Support:
1-800-526-0288
www.aerco.com
(Mon–Fri, 8am-5pm EST)
Disclaimer
The information contained in this manual is subject to change without notice from AERCO International,
Inc. AERCO makes no warranty of any kind with respect to this material, including but not limited to
implied warranties of merchantability and fitness for a particular application. AERCO International is not
liable for errors appearing in this manual. Nor for incidental or consequential damages occurring in
connection with the furnishing, performance, or use of this material.
MC2: 04/23/13 Page 2 of 144
GF-131
AERCO Control System (ACS)
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, New York 10913 • Phone: 800-526-0288
OMM-0081_0D
Table of Contents
FOREWARD ................................................................................................................... 9
PHRASES, ABBREVIATIONS & ACRONYMS .......................................................... 9
1. ACS GENERAL INFORMATION ........................................................................... 11
1.1 SAFETY PRECAUTIONS AND WARNINGS .................................................. 11
1.2 INTRODUCTION .............................................................................................. 11
1.3 ACS GENERAL DESCRIPTION ...................................................................... 11
1.4 ACS FEATURES ............................................................................................. 12
1.4.1 Simplified Installation and Set-Up ........................................................... 12
1.4.2 User-Friendly Control System Interface ................................................. 12
1.4.3 Retention of Menu Option Settings ......................................................... 13
1.4.4 Application Flexibility .............................................................................. 13
1.4.5 Sequential or Parallel Operation ............................................................. 13
1.4.6 Accuracy ................................................................................................ 13
1.4.7 Bumpless Transfer ................................................................................. 13
1.4.8 Fault Alarm Surveillance ........................................................................ 13
1.4.9 ACS Programming Via RS232 Port. ....................................................... 13
2. ACS INSTALLATION ............................................................................................. 15
2.1 INTRODUCTION .............................................................................................. 15
2.2 SITE SELECTION AND MOUNTING .............................................................. 15
2.2.1 Mounting the ACS .................................................................................. 15
2.3 SITE SELECTION AND MOUNTING .............................................................. 16
2.4 POWER WIRING ............................................................................................. 17
2.5 SENSOR INSTALLATION AND WIRING ........................................................ 18
2.5.1 Header Sensor Installation ..................................................................... 19
2.5.2 Return Sensor Installation ...................................................................... 19
2.5.3 Outdoor Air Sensor Installation............................................................... 20
2.6 RS485 (MODBUS) WIRING AT THE ACS ...................................................... 22
2.6.1 ACS Bias Switches & Loop Termination Resistors ................................. 22
2.7 RS485 (MODBUS) WIRING, BIAS, AND TERMINATION AT AERCO
2.7.1 RS485 Wiring, Termination& Bias for Benchmark Series and KC1000 Boilers . 23
2.7.2 RS485 Wiring for Modulex Series Boilers .............................................. 29
2.8 SAMPLE RS485 (MODBUS) NETWORK DIAGRAMS ................................... 30
2.9 RS485 WIRING AT THE ACS ......................................................................... 31
BOILERS ................................................................................................................... 23
MC2: 04/23/13 Page 3 of 144
GF-131
AERCO Control System (ACS)
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, New York 10913 • Phone: 800-526-0288
OMM-0081_0D
2.10 INTERLOCK WIRING ...................................................................................... 32
2.10.1 Interlock 1 (INT 1) Wiring ....................................................................... 32
2.10.2 Interlock 2 (INT 2) Wiring ....................................................................... 32
2.11 SETBACK WIRING ......................................................................................... 32
2.12 RELAY WIRING ............................................................................................... 32
2.12.1 System Start Relay ................................................................................. 33
2.12.2 Fault Alarm Relay ................................................................................... 33
2.12.3 Auxiliary Relay ........................................................................................ 33
2.13 4-20 MA WIRING ............................................................................................. 33
2.14 MOUNTING AND WIRING THE OPTIONAL ACS RELAY BOX ..................... 33
2.15 RELAY PANEL INSTALLATION AND WIRING .............................................. 34
2.16 RELAY PANEL COMPONENTS ..................................................................... 39
2.16.1 Power ..................................................................................................... 39
2.16.2 Inputs .................................................................................................... 39
2.16.3 Outputs .................................................................................................... 39
2.17 RELAY PANEL OPERATION .......................................................................... 40
2.18 ACS PROGRAMMING FOR USE WITH THE ACS RELAY PANEL ............... 41
2.18.1 RS485 Menu .......................................................................................... 41
2.18.2 Configuration Menu ................................................................................ 41
3. OPERATION .......................................................................................................... 43
3.1 INTRODUCTION .............................................................................................. 43
3.2 FRONT PANEL OPERATING CONTROLS AND DISPLAYS ......................... 43
3.3 ACS MENU STRUCTURE ............................................................................... 45
3.3.1 Menu Processing Procedure .................................................................. 45
3.4 OPERATING MENU ........................................................................................ 47
3.4.1 HEADER TEMP AND PERCENT OF LOAD .......................................... 47
3.4.2 HEADER SETPOINT ............................................................................. 47
3.4.3 OUTSIDE AIR TEMP ............................................................................. 47
3.4.4 I/O STATUS ........................................................................................... 48
3.4.5 RETURN TEMP ..................................................................................... 48
3.4.6 NETWORK BOILER OUTLET TEMPERATURE .................................... 48
3.4.7 NETWORK BOILER ERROR CODE ...................................................... 48
3.5 SETUP MENU .................................................................................................. 48
3.5.1 ENTER PASSWORD ............................................................................. 49
3.5.2 DATE AND TIME MENU OPTIONS ....................................................... 49
3.6 RS232 MENU ................................................................................................... 49
MC2: 04/23/13 Page 4 of 144
GF-131
AERCO Control System (ACS)
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, New York 10913 • Phone: 800-526-0288
OMM-0081_0D
3.6.1 RS232 MODE......................................................................................... 49
3.6.2 RS232 BAUD RATE ............................................................................... 49
3.6.3 MODBUS ADDRESS ............................................................................. 49
3.6.4 NETWORK TIMEOUT ............................................................................ 50
3.6.5 MODBUS PASS THRU .......................................................................... 50
3.7 RS232 MENU ................................................................................................... 50
3.7.1 RS485 BAUD RATE ............................................................................... 50
3.7.2 MIN SLAVE ADDR ................................................................................. 50
3.7.3 MAX SLAVE ADDR ................................................................................ 50
3.7.4 NUMBER NETWK BLRS ....................................................................... 50
3.7.5 MODBUS CNTL TYPE ........................................................................... 50
3.7.6 NETW BOILER Xx ADDRESS=Yyy ....................................................... 51
3.8 FIELD ADJUST MENU .................................................................................... 51
3.8.1 HEADER SET MODE ............................................................................. 51
3.8.2 HDR HIGH LIMIT ................................................................................... 51
3.8.3 HDR LOW LIMIT .................................................................................... 51
3.8.4 INTERNAL SETPT ................................................................................. 51
3.8.5 RESET RATIO ....................................................................................... 51
3.8.6 BLDG REF TEMP .................................................................................. 52
3.8.7 REMOTE SIGNAL .................................................................................. 52
3.8.8 OFFSET ENABLE .................................................................................. 52
3.8.9 Offset Menu Options .............................................................................. 52
3.8.10 Setting Up an Offset Schedule ............................................................... 52
3.8.11 Setting Up a Manual Offset Schedule .................................................... 53
3.9 CONFIGURATION MENU ............................................................................... 53
3.9.1 BLR CNTL SELECT ............................................................................... 53
3.9.2 BOILER OP MODE ................................................................................ 53
3.9.3 PARALLEL MODE ................................................................................. 54
3.9.4 SEQUENTIAL......................................................................................... 54
3.9.5 SYS INTLK CONFIG .............................................................................. 54
3.9.6 BLR START LEVEL ............................................................................... 54
3.9.7 BLR STOP LEVEL ................................................................................. 54
3.9.8 MAX POWER INPUT ............................................................................. 55
3.9.9 FAIL SAFE MODE .................................................................................. 55
3.9.10 LEAD BLR SELECT (Lead Boiler Selection) .......................................... 55
3.9.11 LAST BLR SELECT (Last Boiler Selection) ........................................... 55
3.9.12 ROTATE TIME ....................................................................................... 55
3.9.13 RET SENSOR MODE (Return Sensor Mode) ........................................ 55
3.9.14 PLANT DT LIMIT (Plant Delta-Temperature Limit) ................................. 55
3.9.15 BOILER DELAY ..................................................................................... 56
MC2: 04/23/13 Page 5 of 144
GF-131
AERCO Control System (ACS)
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, New York 10913 • Phone: 800-526-0288
OMM-0081_0D
3.9.16 DHW OPTION (Domestic Hot Water Option) ......................................... 56
3.9.17 NUMBER DHW BLRS (Number of Domestic Hot Water Boilers) ........... 56
3.9.18 DHW SIGNAL (Domestic Hot Water Signal) .......................................... 57
3.9.19 NUM DHW PRIORITY (Number of DHW Priority Boilers) ...................... 57
3.9.20 VALVE WAIT STATES ........................................................................... 57
3.9.21 SYS RELAY OPTION (System Relay Option) ........................................ 57
3.10 BOOST TEMP ................................................................................................. 57
3.10.1 RET TEMP BST DIS (RETURN TEMPERATURE BOOST DISABLE) . 57
3.10.2 BOOST MAX TIMER .............................................................................. 58
3.11 TUNING MENU ................................................................................................ 58
3.11.1 PROPORTIONAL BND .......................................................................... 58
3.11.2 INTEGRAL GAIN .................................................................................... 58
3.11.3 DERIVATIVE GAIN ................................................................................ 59
3.11.4 Decreasing Boiler Cycles ....................................................................... 59
3.11.5 HI_DB_SETPT_EN (High Deadband Setpoint Enable) .......................... 59
3.11.6 DEADBAND HIGH ................................................................................. 59
3.11.7 DEADBAND LOW .................................................................................. 59
3.11.8 SETPT DOWN RATE (Setpoint Down (descending) Rate ..................... 59
3.11.9 DEMAND OFFSET ................................................................................. 59
3.12 RELAY MENU ................................................................................................. 60
3.12.1 SYS START TEMP ................................................................................ 60
3.12.2 SYS START OPTION ............................................................................. 60
3.12.3 SYS START INTLK ................................................................................ 60
3.12.4 AUX RELAY OPEN ................................................................................ 60
3.12.5 AUX RELAY CLOSE .............................................................................. 60
3.12.6 FAULT ALRM RELAY ............................................................................ 60
3.12.7 FAULT ALARM BLRS ............................................................................ 61
3.12.8 FAULT ALRM CLEAR ............................................................................ 61
3.13 CALIBRATION MENU ..................................................................................... 61
3.13.1 HDR SENS OFFSET .............................................................................. 61
3.13.2 OUTD SENS OFFSET ........................................................................... 61
3.13.3 4 - 20 MA OFFSET ................................................................................. 61
3.13.4 RETN SENS OFFSET ............................................................................ 61
3.13.5 RAMP UP %/MIN ................................................................................... 61
3.13.6 RAMP DOWN %/MIN ............................................................................. 62
3.13.7 RESET DEFAULTS ................................................................................ 62
3.13.8 PASSTHRU WRITE ............................................................................... 62
3.13.9 VALVE WAIT TIME ................................................................................ 62
3.13.10 SYSTEM OVERRIDE (Modbus Enable/Disable) .................................... 62
MC2: 04/23/13 Page 6 of 144
GF-131
AERCO Control System (ACS)
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, New York 10913 • Phone: 800-526-0288
OMM-0081_0D
3.14 ACS QUICK-START GUIDE MENU ................................................................ 63
3.14.1 CONSTANT SETPT MODE (Default): .................................................... 64
3.14.2 REMOTE SETPT MODE: ....................................................................... 65
3.14.3 OUTDOOR RESET MODE .................................................................... 66
4. PROGRAMMING ACS OPERATING MODES ....................................................... 67
4.1 INTRODUCTION .............................................................................................. 67
4.2 OUTDOOR RESET MODE .............................................................................. 67
4.2.1 Selecting Outdoor Reset Mode .............................................................. 68
4.2.2 Determining Reset Schedule .................................................................. 68
4.2.3 Entering Reset Ratio and Building Reference Temperature ................... 69
4.2.4 SELECTING BOILER OPERATING MODE ........................................... 69
4.2.5 Entering System Start Temperature ....................................................... 70
4.2.6 Entering Boiler Start and Boiler Stop Levels .......................................... 70
4.3 REMOTE SETPOINT MODE ........................................................................... 71
4.3.1 Selecting Remote Setpoint Mode ........................................................... 71
4.3.2 Entering Header High Limit and Low Limit Temperatures ...................... 72
4.3.3 Selecting Remote Signal Type ............................................................... 73
4.3.4 Selecting Boiler Operating Mode ............................................................ 73
4.3.5 Entering Boiler Start & Stop Levels ........................................................ 74
4.4 CONSTANT SETPOINT MODE ....................................................................... 74
4.4.1 Selecting Constant Setpoint Mode ......................................................... 75
4.4.2 Selecting Internal Setpoint Temperature ................................................ 75
4.4.3 Selecting Boiler Operating Mode ............................................................ 76
4.4.4 Entering Boiler Start and Boiler Stop Levels .......................................... 76
4.5 “Temp and Load” Option............................................................................... 76
4.6 “Start Enabled” Option .................................................................................. 77
4.7 System Initialization and Polling .................................................................. 77
4.8 Testing the System ........................................................................................ 78
5. TROUBLESHOOTING ........................................................................................... 81
5.1 Fault Messages And Common Problems ..................................................... 81
APPENDIX A: ACS MENUS ...................................................................................... 85
APPENDIX B: STATUS AND FAULT MESSAGES ..................................................... 91
B.1 C-MORE STATUS AND FAULT MESSAGES .................................................. 91
B.3 Deciphering the “FAULT Code” Reading from the BCM (used in Modulex
MC2: 04/23/13 Page 7 of 144
B.2 CONVERSION EQUATIONS FOR TEMPERATURE VARIABLES .................. 96
Boilers) ..................................................................................................................... 97
B.4 BCM (BOILER COMMUNICATION MODULE) FAULT CODES ....................... 98
GF-131
AERCO Control System (ACS)
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, New York 10913 • Phone: 800-526-0288
OMM-0081_0D
APPENDIX C: RESET SCHEDULE AND OUTDOOR RESET RATIO CHARTS ..... 105
B.5 BCM (BURNER MANAGEMENT MODULE) FAULT CODES .......................... 99
B.6 ACS (AERCO CONTROL SYSTEM) I/O STATUS .......................................... 102
C.1 USING THE CHARTS TO DETERMINE RESET SCHEDULE ........................ 105
APPENDIX D: NTC TEMPERATURE SENSOR RESISTANCE ............................... 111
APPENDIX E: ACS WIRING DIAGRAM ................................................................... 113
APPENDIX F: ACS PARTS AND ACCESSORIES ................................................... 115
APPENDIX G: PROGRAMMING USING RS232 COMMUNICATION ....................... 117
G.1 INTRODUCTION ............................................................................................. 117
G.2.1 Logging on to a Remote Machine Using PuTTY .................................... 117
G.2.2 Running a Command on a Remote Machine Using PuTTY ................... 118
G.3 RS232 COMMUNICATION SET-UP ................................................................ 119
APPENDIX H: ACS MODBUS ADDRESS ASSIGNMENTS .................................................. 127
H.1 ACS CONTROLLER STANDARD INPUT REGISTER ASSIGNMENTS ........ 127
APPENDIX I: BOILER START AND STOP LEVELS ............................................... 143
C.2 DETERMINING RESET SCHEDULE BY FORMULA ...................................... 105
G.2 AQUIRING THE PuTTY APPLICATION .......................................................... 117
G.4 PROGRAMMING PROCEDURE ..................................................................... 119
H.2 ACS CONTROLLER STANDARD HOLDING REGISTER ASSIGNMENTS ... 134
MC2: 04/23/13 Page 8 of 144
GF-131
AERCO Control System (ACS)
OMM-0081_0D
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, New York 10913 • Phone: 800-526-0288
Phrase, Abbreviation or
A (Amp)
Ampere
ACS
AERCO Control System
ADDR
Address
ALRM
Alarm
AUX
Auxiliary
Building Automation System, often used interchangeably with EMS (see below)
Symbol rate, or simply the number of distinct symbol changes (signaling
each symbol is 1 bit long.
BCM
Boiler Control Module used with AERCO Modulex Series Boilers
BLR
Boiler
BND
Band
A pair of resistors used to force the communication line to a definite logic state so that noise is not picked up as invalid data during communication.
BLDG (Bldg)
Building
C-More Controller (or Control Box)
A control system developed by AERCO and currently used in all Benchmark and KC1000 Series product lines.
CNTL
Control
DHW
Domestic Hot Water
DYN
Dynamic
EMS
Energy Management System; often used interchangeably with BAS
Ethernet
A computer networking technology for Local Area Networks (LANs)

FOREWARD

The AERCO Control System (ACS) is AERCO’s solution for a flexible boiler plant controller. The system can control a boiler plant comprised of AERCO Benchmark Series, Modulex Series or KC1000 Boilers. The ACS can stage and coordinate the operation of up to thirty-two (32) AERCO Boilers with maximized efficiency. With individual boilers with turn-down ratios as high as 20:1, a 5-boiler plant can deliver a system turn-down ratio of 100:1 when the boilers are staged to operate sequentially.
The ACS can also be used in a combination boiler plant to both supply building heat and also heat water for domestic applications. There are multiple options built in to do this. Some of these options require a mated AERCO Relay Box to be installed along with the ACS in order to effectively and safely control the supporting hydronic valves and their interaction with the boilers.
The ACS is fully compatible with a wide array of Building Automation Systems (BAS) or Energy Management Systems (EMS) utilizing Modbus Protocol. The BAS or EMS communicates with the ACS utilizing a RS232 interface. If the BAS or EMS uses a RS485 port, the ACS can be ordered with a RS485-to-RS232 Converter which can be easily installed within the ACS wiring compartment.

PHRASES, ABBREVIATIONS & ACRONYMS

The phrases, abbreviations and acronyms used in this document are listed in the following
table:
Phrases, Abbreviations and Acronyms
Acronym
BAS
Baud Rate
Bias Resistors
events) transmitted per second. It is not equal to bits per second, unless
Meaning
MC2: 04/23/13 Page 9 of 144
GF-131
AERCO Control System (ACS)
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, New York 10913 • Phone: 800-526-0288
OMM-0081_0D
Phrase, Abbreviation
FDX
Full-Duplex
FLT
Fault
GND
Ground
HDR
Header
HDX
Half-Duplex
Hex
Hexadecimal Number (0 - 9, A - F)
Hz
Hertz (Cycles Per Second)
INTLK
Interlock
I/O
Input/Output
Input/Output (I/O) Box currently used on all Benchmark and KC Series products
IP
Internet Protocol
ISO
Isolated
LSB
Least Significant Byte
LSD
Least Significant Digit
MA (mA)
Milliampere
MAX (Max)
Maximum
MIN (Min)
Minimum
A serial, half-duplex data transmission protocol developed by AEG Modicon
MSB
Most Significant Byte
MSD
Most Significant Digit
MS/TP
Master-Slave/Token-Passing (usually over RS485 networks)
OFFS
Offset
OUTD
Outdoor
PTP
Point-to-Point (usually over RS232 networks)
REF (Ref)
Reference
Response Time
The maximum amount of time allowed to receive a response to a request
RS232 (or EIA-232)
A standard for serial, full-duplex (FDX) transmission of data based on the RS232 Standard
RS422 (or EIA-422)
A standard for serial, full-duplex (FDX) transmission of data based on the RS422 Standard
RS485 (or EIA-485)
A standard for serial, half-duplex (HDX) transmission of data based on the RS485 Standard
RTN
Return
RTU
Remote Terminal Unit
SEN
Sensor
SETPT (Setpt)
Setpoint Temperature
SHLD (Shld)
Shield
SLTA
Serial LonTalk Adapter
SYS
System
TEMP (Temp)
Temperature
A resistor placed at each end of a daisy-chain or multi-drop network in
communication
VAC
Volts, Alternating Current
VDC
Volts, Direct Current
VFD
Vacuum Fluorescent Display
Phrases, Abbreviations and Acronyms (Continued)
or Acronym
I/O Box
Modbus®
Meaning
Terminating Resistor
MC2: 04/23/13 Page 10 of 144
order to prevent reflections that may cause invalid data in the
GF-131
AERCO Control System (ACS)
OMM-0081_0D
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, New York 10913 • Phone: 800-526-0288
Dimensions
Weight
Power Requirements

1. ACS GENERAL INFORMATION

1.1 SAFETY PRECAUTIONS AND WARNINGS

The warnings and cautions appearing throughout this manual should be reviewed and thoroughly understood prior to attempting to install, operate, troubleshoot or repair the ACS Controller.

1.2 INTRODUCTION

This manual provides installation, operation and troubleshooting instructions for the AERCO Control System, Model 5R5-384.

1.3 ACS GENERAL DESCRIPTION

The ACS (Figure 1-1) is a rugged, flexible controller designed to stage and coordinate the operation of up to 32 AERCO Benchmark Series, Modulex Series or KC1000 Boilers while maximizing operational efficiency. Under normal load conditions, the ACS can precisely regulate the header temperature of the boiler plant within ±2°F.
Boiler plant control is accomplished via a RS485 network utilizing Modbus protocol. For facilities that have taken a building-wide approach to energy efficiency, the ACS can be easily integrated with an Energy Management System (EMS) or Building Automation System (BAS) utilizing Modbus protocol. Physical connection to the remote EMS or BAS is accomplished via an RS232 interface. EMS/BAS integration will also permit utilization of the pass-thru function incorporated in the ACS. The pass-thru function permits the remote system to monitor up to 35 operating parameters from each boiler in the plant.
The ACS is housed in a NEMA 13 enclosure. A hinged clear-plastic cover over the unit’s panel controls protects against incidental contact of control settings and provides a degree of protection against airborne debris and the spraying or splashing of water. The physical dimensions, weight and electrical power requirements for the ACS are as follows:
Each ACS shipment includes a Header Sensor Kit, Part No. GM-122790 which is required for all modes of operation. Other available options which can be ordered with your shipment include:
• Outdoor Air Sensor Kit, Part No. GM-122781: Required for Outdoor Reset Mode
Operation
9.50” W x 7.25” H x 4.00” D
3 lbs.
85-to-265 VAC, Single-Phase, 50-60 Hz @ 1A
• Return Sensor Kit, Part No. 122790 (Same as Header Sensor Kit): Used for external
monitoring of boiler water return temperature
• RS485-to-RS232 Converter, Part No 124943: For use with EMS or BAS equipment that
has a RS485 Port
MC2: 04/23/13 Page 11 of 144
GF-131
AERCO Control System (ACS)
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, New York 10913 • Phone: 800-526-0288
OMM-0081_0D
Cover
Clear Plastic
Front Panel
Wiring Compartment Cover
Figure 1-1: AERCO Control System (ACS)

1.4 ACS FEATURES

The following paragraphs briefly describe some of the unique features incorporated in the ACS.

1.4.1 Simplified Installation and Set-Up

The ACS system operates on single-phase input power ranging from 85 to 265 VAC, 50-60 Hz. Connections to the boiler plant are accomplished utilizing a 2-wire RS485 network connected in a daisy-chain configuration. When an EMS or BAS is used with the ACS, connections are made via the RS232 port terminals. In the event that the EMS or BAS is not equipped with a RS232 port, the ACS can be ordered with a RS485 to RS232 Converter which can be easily installed within the wiring compartment of the ACS. With the exception of AC power, interlock and setback inputs and relay outputs, ACS connections are accomplished using shielded-twisted pair cable.

1.4.2 User-Friendly Control System Interface

The unit incorporates a menu-driven architecture which is comprised of 9 primary menus. The user interface to these menus is accomplished via the ACS control panel and a Vacuum Fluorescent Display (VFD). The display is capable of displaying two lines with 16 characters per line. Virtually all of the control panel keys are identical to the C-More Control System currently used on AERCO Benchmark Series and KC1000 Boilers. This commonality will help simplify the time required for system setup of the ACS.
MC2: 04/23/13 Page 12 of 144
GF-131
AERCO Control System (ACS)
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, New York 10913 • Phone: 800-526-0288
OMM-0081_0D

1.4.3 Retention of Menu Option Settings

By using non-volatile memory, the ACS retains program and menu settings during shut-down or when input AC power is interrupted. Settings can be retained for more than 2 years.

1.4.4 Application Flexibility

Four different configuration options can be selected to match the needs of any closed-loop system. These configurations are: Outdoor Reset, Constant Setpoint, Remote Setpoint via a 4­20 Ma input and Remote Setpoint via Modbus.
Three different domestic hot water (DHW) options are selectable for controlling the combination boilers and valves that are being used to provide heated domestic water.

1.4.5 Sequential or Parallel Operation

Boilers can be programmed for either sequential or parallel operation using the ACS keypad controls. When set for sequential operation, the boilers are brought on-line one at a time as needed. When set for parallel operation, the boilers are all brought on-line together at the same firing rate.

1.4.6 Accuracy

Using PID (Proportional Integral Derivative) and Ramp-Up/Ramp-Down Modulation Control Algorithms, the ACS provides dynamic responses to all changes in boiler plant operation. Header temperatures, as well as percentages of boiler input are precisely controlled with virtually no over-shoot or short-cycling of boiler units. A header temperature accuracy of ±2°F is virtually assured during continuous plant operation.

1.4.7 Bumpless Transfer

When operated sequentially, The ACS stages boilers on and off at selectable firing rate percentages. The result is a seamless transition with undetectable room temperature changes. In addition, when in sequential mode, the ACS sequences boilers using a first-on, first-off basis, thereby equalizing the accumulated run time of all boilers in the plant.
The ACS also continuously monitors the number of Boilers that are available for operation. In the event of a boiler malfunction, or required servicing, the ACS automatically compensates for a lack of response from any unit and brings on the next available boiler to satisfy the demand. This feature operates in both sequential and parallel modes.

1.4.8 Fault Alarm Surveillance

If an EMS or BAS is not used with the ACS to monitor faults, a Fault Alarm Relay can be activated thereby notifying facility managers of faults associated with the ACS.

1.4.9 ACS Programming Via RS232 Port.

If desired, the ACS can be programmed by connecting a Laptop Computer or other terminal emulation device to the RS232 Port terminals on the ACS. Detailed set-up instructions and available command listings are provided in Appendix G. Most settings are also programmable using Modbus.
MC2: 04/23/13 Page 13 of 144
GF-131
AERCO Control System (ACS)
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, New York 10913 • Phone: 800-526-0288
OMM-0081_0D
(This page intentionally blank)
MC2: 04/23/13 Page 14 of 144
GF-131
AERCO Control System (ACS)
OMM-0081_0D
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, New York 10913 • Phone: 800-526-0288

2. ACS INSTALLATION

2.1 INTRODUCTION

This Chapter provides the descriptions and procedures necessary to mount the ACS and connect all boiler plant units and applicable sensors. Guidelines are also provided for connection of an EMS or BAS being used with the system. Refer to the wiring diagram provided in Appendix E when making all wiring connections to the ACS.

2.2 SITE SELECTION AND MOUNTING

Ensure that the site selected for installation of the ACS provides the following:
Access to single-phase AC power from 110 to 240 VAC, 60 Hz nominal
Sufficient clearances to permit maintenance and setup/operational tasks on the ACS.

2.2.1 Mounting the ACS

AERCO recommends that the ACS be wall-mounted using a sheet of plywood or other suitable material. For easy viewing, the ACS controls and display should be at eye level. Mounting is accomplished using three screws (not provided). The spacing for the three screws are indicated on the rear of the ACS in millimeters. Figure 2-1 shows the rear of the panel enclosure and also indicates the required spacing for the three mounting screws in inches. Proceed as shown below, to mount the unit:
Mounting the ACS Controller
1. First install a screw on the mounting surface at the top center location shown in Figure 2-1. Leave a space of approximately 1/8 inch between the mounting surface and the head of the screw.
2. Remove the wiring compartment cover from the front of the ACS (see Figure 1-1) to provide access to the slots for the two lower mounting screw locations.
3. Hang the ACS on the installed top screw. Position the unit so it is level.
4. Mark the locations for the two lower screws.
5. Remove the ACS and drill two pilot holes for the lower screws.
6. Replace the ACS on the installed top-center screw.
7. Secure the ACS to the wall by installing the two lower screws. DO NOT over-tighten the screws.
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GF-131
AERCO Control System (ACS)
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, New York 10913 • Phone: 800-526-0288
OMM-0081_0D
198 mm (7.8")
145 mm (5.7")
15 mm
(0.6")
REAR VIEW
Figure 2-1: ACS Mounting Provisions

2.3 SITE SELECTION AND MOUNTING

All wiring connections to the ACS are made at the terminals located behind the wiring compartment cover as shown in Figure 2-2. Run all wiring through the knock-outs provided on the bottom surface of the unit. Shielded, twisted-pair cable should be used for sensor and communication wiring. This wiring should be 18 to 24 AWG. Examples of suitable sensor and communication wire are: Belden 9841, 8761, 3105A or equivalent. AC power wiring should be 14 to 18 AWG. The ACS wiring diagram is provided in Appendix E. Once mounting is complete and the ACS is secured in place, loosen the two captive screws on the wiring compartment cover using a Phillips screwdriver. Feed all wiring through the knock-outs provided on the bottom of the panel.
NOTE
Refer to the wiring diagram provided in Appendix E when making all wiring connections to the ACS.
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GF-131
AERCO Control System (ACS)
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, New York 10913 • Phone: 800-526-0288
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Wiring ACS Power Connections
DO NOT apply power to the ACS until all of the required external connections
THE ACS CAN BE POWERED BY SINGLE-PHASE AC VOLTAGES RANGING FROM 85 TO 265 VAC. THEREFORE, EXERCISE EXTREME CARE WHEN CONNECTING POWER WIRING TO THE UNIT. ENSURE THAT THE EXTERNAL CIRCUIT BREAKER SUPPLYING LINE VOLTAGE TO THE ACS IS TURNED OFF TO AVOID SEVERE ELECTRICAL SHOCK.

2.4 POWER WIRING

Use 14 to 18 AWG wire for AC power connections and proceed as shown below:
1. Feed the power wiring through the right-most knock-out in the bottom of the panel enclosure (Figure 2-2).
2. Connect the Line (black), Neutral (white) and Ground (green) wire leads to the L, N and (GND) terminals. The terminal blocks can be detached from the ACS headers
if necessary to simplify field wiring connections.
3. Following completion of power wiring, turn on the external circuit breaker or switch and apply power to the unit. The ACS display will momentarily show:
AERCO ACS
REV X.XX
(Where: X.XX represents the revision level of the installed ACS software)
4. Next, since the Header Sensor is not yet installed, the display will then show:
HEADER TEMP
SENSOR ERROR
The red FAULT LED indicator will also light and a fault message will alternately be displayed as follows:
HEADER SENSOR
ERROR
5. Press the ON-OFF key on the keypad. The green ON LED indicator will light and the ACS display will continue to show the above message.
6. After verifying proper power connections, press the ON-OFF key. The ON LED will turn off.
7. Turn off the external power switch and/or circuit breaker. The ACS display will go blank.
8. described in paragraphs 2.5 through 2.11 have been completed.
MC2: 04/23/13 Page 17 of 144
GF-131
AERCO Control System (ACS)
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, New York 10913 • Phone: 800-526-0288
OMM-0081_0D
Figure 2-2: ACS with Wiring Compartment Cover Removed

2.5 SENSOR INSTALLATION AND WIRING

Two types of sensors may be installed, including a Header Sensor and an Outside Air Sensor. The Header Sensor is required for all modes of operation. The Outdoor Air Sensor is required for operation in the Outdoor Reset Mode. All Sensor wiring should be run separately from power wiring to avoid inducing electrical noise on the sensor wiring.
If desired, an optional Return Sensor may also be installed, which is the same type and part number as the Header Sensor, however it is only used for Plant DT limit operation and for monitoring purposes.
MC2: 04/23/13 Page 18 of 144
GF-131
AERCO Control System (ACS)
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, New York 10913 • Phone: 800-526-0288
OMM-0081_0D
Header Sensor Installation
Return Sensor Installation

2.5.1 Header Sensor Installation

A Header Sensor Kit, (part no. 122790) is provided with the ACS. This Kit contains the Header Sensor (64038), a Thermowell (122758) and some heat conductive grease which MUST be used with the Sensor. When installing the Sensor, use a 1/2 inch NPT tapped coupling or a 4 x 4 x 1/2 inch Tee fitting. Shielded pair, 18 AWG cable (Belden # 8760 or equiv.) is recommended for Header Sensor wiring. The Header Sensor must be installed between 2 and 10 feet downstream of the LAST boiler in the boiler plant’s supply water header. Install the Header Sensor as shown below:
NOTE
The Header Sensor is a thermistor type sensor. The Resistance vs. Temperature Chart for this sensor is provided in Appendix D. Length of Header Sensor wire leads should not exceed 600 feet.
1. Refer to Figure 2-3 for the Header Sensor installation details.
2. Install the Header Sensor and Thermowell into the 1/2 inch NPT tapped coupling or a 4 x
4 x 1/2 inch Tee fitting using heat-conductive grease provided. This will aid in its response.
3. For proper response, ensure that the Header Sensor probe is inserted at least 2 inches into the water flow.
4. Using shielded pair cable (Belden #8760 or equiv.) connect the Header Sensor leads to HDR SEN terminals 4 and 5 on the ACS. There is no polarity to observe when making these connections.
5. Terminate the cable shield at SHLD terminal 3 of the ACS. DO NOT terminate the shield at the Sensor end of the cable.

2.5.2 Return Sensor Installation

The Return Sensor is required to activate the Plant Delta Temperature function, as described in
section 3.9.14, on page 54.
As mentioned in paragraph 2.5, the Return Sensor is identical to the Header Sensor.
Therefore, if a Return Sensor is being installed, another Header Sensor Kit (part no. 122790) is
required. The Return Sensor should be installed in the boiler water return line within 3 feet of the
first boiler in the boiler plant’s return water line. The installation details shown in Figure 2-3 for
the Header Sensor also apply to the Return Sensor. If used, install the Return Sensor as shown
below:
1. Refer to Figure 2-3 and install the Return Sensor and Thermowell into the 1/2 inch tapped coupling or or Tee fitting using heat conductive grease.
2. Using shielded pair cable (Belden #8760 or equiv.), connect Return Sensor leads to terminals 6 and 5 on the ACS. There is no polarity to observe when making these connections.
3. Terminate the cable shield at SHLD terminal 3 of the ACS. DO NOT terminate the shield at the Sensor end of the cable.
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GF-131
AERCO Control System (ACS)
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, New York 10913 • Phone: 800-526-0288
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PROBE DEPTH MUST EXTEND AT LEAST 2" INTO PIPE
WELDED 1/2" COUPLING OR 4"x4*x1/2" T - FITTING
HEADER SENSOR WITH THERMOWELL INSTALLED
Outdoor Air Sensor Installation
Figure 2-3: Header Sensor Installation Details

2.5.3 Outdoor Air Sensor Installation

The Outdoor Air Temperature Sensor (part no. GP-122662) is required when operating in the ACS in the Outdoor Reset Mode (paragraph 4.2). An Outdoor Air Sensor Kit (part no. GM-
122781) is also available. This kit contains the Sensor (GP-122662) and a Mounting Bracket for wall mounting. The Outdoor Air Sensor should be mounted on the North side of the building, shielded from direct sunlight, and away from air intakes or outlets from the building. Shielded pair 18 AWG cable (Belden # 8760 or equiv.) is recommended for sensor wiring. The Outdoor Air Sensor can be mounted up to 600 feet from the ACS. See instructions below.
NOTE
The Outdoor Air Sensor is a thermistor type sensor. The Resistance vs. Temperature Chart for this sensor is provided in Appendix E. Length of Header Sensor wire leads should not exceed 600 feet.
1. Refer to Figure 2-4 for a typical Outdoor Air Sensor installation.
2. Attach the sensor to the mounting bracket and secure the bracket in a suitable location on the North side of the building.
3. Using shielded pair cable (Belden #8760 or equiv.), connect the two Sensor leads to terminals 1 and 2 on the ACS. There is no polarity to observe when connecting the sensor.
4. Terminate the cable shield at SHLD terminal 3 of the ACS. DO NOT terminate the shield at the Sensor end of the cable.
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GF-131
AERCO Control System (ACS)
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INSTALL SENSOR ON NORTH FACING WALL OUT OF DIRECT SUNLIGHT AND AWAY FROM ALL AIR INLETS/OUTLETS
Figure 2-4: Outdoor Air Sensor Installation
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GF-131
AERCO Control System (ACS)
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, New York 10913 • Phone: 800-526-0288
OMM-0081_0D
MASTER
SLAVE
#1
SLAVE
#2
SLAVE#3SLAVE#4SLAVE
#5
Positioning the Two Bias Switches
details.

2.6 RS485 (MODBUS) WIRING AT THE ACS

The ACS communicates with the AERCO Boilers over a RS485 network using Modbus protocol. All Modbus networks are implemented utilizing a Master/Slave scenario where only one device, the Master, can initiate a communication sequence. AERCO Boilers equipped with C-More or E8/BCM (Modulex) control systems can only function as Slaves on a Modbus network. However, the ACS can function as a Master controlling C-More or BCM Boiler Slaves, or as a Slave controlled by an Energy Management System (EMS) developed by other manufacturers. Additional information on implementing Modbus networks is provided in AERCO Modbus Communication Manual GF-114.
RS485 (Modbus) networks are wired in a “daisy chain” configuration similar to the example shown in Figure 2-5. Shielded twisted-pair, 18 – 24 AWG cable (Belden #9841, #3105A, #8760 or equiv.) is recommended for RS485 wiring connections.
Figure 2-5: Typical Daisy-Chain Modbus/RS485 Network
At the ACS, RS485 (Modbus) wiring connections are made at the wiring terminals labeled 485 B+ and 485 A-. The cable shield is terminated at the SHLD terminal (3) of the ACS.

2.6.1 ACS Bias Switches & Loop Termination Resistors

Each ACS contains a built-in 120 ohm loop termination resistor and two bias DIP switches which are mounted on the lower portion of the motherboard (Figure 2-6). The 120 ohm termination resistor is always active and is designed to match the electrical impedance at the ACS end of the RS485 loop. Therefore, only one additional termination resistor will be required at the boiler end of the RS485 loop. The two bias switches are used to activate or deactivate bias voltage on the RS485 network and should be positioned as follows, depending on the type of AERCO boilers being used. See the instructions below:
NOTE
Refer to paragraph 2.7 for detailed instructions and illustrations describing how to implement loop termination, bias and wiring connections on the RS485 loop.
1. When wiring to Boiler Control Modules (BCMs) controlling Modulex Boilers, the ACS bias switches must be activated by placing them in the on (down or towards wall) position. Loop termination is accomplished by activating the termination resistor in the last BCM on the RS485 loop.
2. When wiring to C-More control systems (Benchmark & KC1000 Boilers), the positions of the ACS bias switches will depend on which one of the two available methods is used. Loop termination will also depend on the method employed. See paragraph 2.7 for
MC2: 04/23/13 Page 22 of 144
GF-131
AERCO Control System (ACS)
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, New York 10913 • Phone: 800-526-0288
OMM-0081_0D
BIAS DIP
SWITCHES
NOTE: THE BIAS DIP SWITCHES CAN BE ACCESSED FROM THE WIRING COMPARTMENT WITHOUT REMOVING THE FRONT PANEL FROM THE UNIT.
WIRING COMPARTMENT
Figure 2-6: Location of ACS DIP Switches

2.7 RS485 (MODBUS) WIRING, BIAS, AND TERMINATION AT AERCO BOILERS

The RS485 wiring connections at the AERCO Boilers will depend on the type of AERCO Boilers and Control Systems being used on the Modbus Network. Benchmark Series and KC1000 Boilers currently utilize C-More Control Systems. Modulex Series Boilers utilize Boiler Control Modules (BCMs) with E8 Controllers.

2.7.1 RS485 Wiring, Termination& Bias for Benchmark Series and KC1000 Boilers

RS485 wiring connections are made at the RS485 terminals of each boiler’s I/O Box (Figures 2­7 or 2-8). However, activating bias and loop termination can be performed using one of two
available methods as described below in Method A and on the following page in Method B. Where possible, Method B is the preferred method.
Method A: For Method A, the bias switches in the ACS are left in the deactivated (up) position. Bias and termination are controlled at the boiler end of the RS485 loop by activating the bias and termination DIP switches on the PMC board of the last C-More Control Box on the daisy­chain. Refer to sheet 1 of Figure 2-7 (Benchmark), or Figure 2-8 (KC1000) and proceed as shown below:
MC2: 04/23/13 Page 23 of 144
GF-131
AERCO Control System (ACS)
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, New York 10913 • Phone: 800-526-0288
OMM-0081_0D
BIAS/Loop Term: METHOD A
towards the operator when using Method 1.
BIAS/Loop Term: METHOD B
in the down or toward the wall position toward the wall.
1. Using a daisy-chain wiring configuration, connect the RS485 positive lead to the RS485 + terminal in the I/O Box for each boiler.
2. Connect the RS485 negative lead to the RS485 - terminal in the I/O Box for each boiler.
3. DO NOT terminate the shields to the Ground (GND) terminal at the boiler end of the RS485 loop. Connect the shields of the incoming and outgoing leads together. The RS485 loop shield should only be terminated at terminal 3 of the ACS.
4. At the last boiler in the daisy-chain, activate the BIAS1, BIAS2 and TERM switches on the PMC board in the C-More Control Box. Refer to GF-114, paragraph 4.3.2 for detailed instructions on accessing the PMC board.
If an Oxygen Sensor is used, ensure that R1 DIP Switch is set to OFF (Disabled). Set it to ON (Enabled) if there is no Oxygen Sensor used.
5. DO NOT activate the bias switches on the ACS. These switches must be in the up position
NOTE
With Method A, the last C-More on the daisy chain must remain powered for the bus to be stable.
The advantage of using Method B is that the bias and termination of the RS485 loop do not require any changes to be made to the DIP switches on the PMC board in the last C-More Control Box. The bus is independent of any C-More control box.
Method B: For Method B, bias is controlled at the ACS by setting the two bias switches (Figure 2-6) to the active (down) position. Termination at the boiler end of RS485 loop is accomplished by activating the “MODBUS R6-ON” switch in the I/O Box in the last boiler on the daisy-chain. If this is an older box, install a 120 ohm, 1/2 Watt termination resistor in the I/O Box of the last boiler on the daisy-chain. Refer to sheet 2 of Figure 2-7 (Benchmark), or Figure 2-8 (KC1000) and proceed as shown below:
1. Using a daisy-chain wiring configuration, connect the RS485 positive lead to the RS485 + terminal in the I/O Box for each boiler.
2. Connect the RS485 negative lead to the RS485 - terminal in the I/O Box for each boiler.
3. DO NOT terminate the shields to the Ground (GND) terminal at the boiler end of the RS485 loop. Connect the shields of the incoming and outgoing leads together. The RS485 loop shield should only be terminated at terminal 3 of the ACS.
4. At the last boiler in the daisy-chain, activate the “MODBUS R6-ON” dipswitch, or install a 120 ohm, 1/2 Watt termination resistor across the RS485 + and - terminals in the boiler’s I/O Box.
5. When using Method 2, activate the two bias switches in the ACS (Figure 2-6) by placing them
MC2: 04/23/13 Page 24 of 144
GF-131
AERCO Control System (ACS)
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(GND) terminal. The shields must be terminated at the
shields of the incoming and
I/O Board
Do not terminate the shields of the RS485 leads to the ground
NOTE
source ends only. Connect the
outgoing RS485 leads together.
METHOD A – BIAS & TERMINATION ACTIVATED AT C-MORE PMC BOARD
Figure 2-7: RS485 (Modbus) Wiring For Benchmark Series Boilers (Sheet 1 of 2)
MC2: 04/23/13 Page 25 of 144
GF-131
AERCO Control System (ACS)
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OMM-0081_0D
of the RS485 leads to the
at the source ends only. Connect the shields of the incoming and outgoing
Connect 120 OHM,
Box.
I/O Board
NOTE
Do not terminate the shields
ground (GND) terminal. The shields must be terminated
RS485 leads together.
½ Watt resister between + and – RS485 terminals on the LAST C-More
METHOD B – TERMINATION ACTIVATED AT I/O BOX
Figure 2-7: RS485 (Modbus) Wiring For Benchmark Series Boilers (Sheet 2 of 2)
MC2: 04/23/13 Page 26 of 144
GF-131
AERCO Control System (ACS)
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OMM-0081_0D
(GND) terminal. The shields must be terminated at the
shields of the incoming and
I/O Board
Do not terminate the shields of the RS485 leads to the ground
NOTE
source ends only. Connect the
outgoing RS485 leads together.
METHOD A – BIAS & TERMINATION ACTIVATED AT C-MORE PMC BOARD
Figure 2-8: RS485 (Modbus) Wiring For KC1000 Boilers (Sheet 1 of 2)
MC2: 04/23/13 Page 27 of 144
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AERCO Control System (ACS)
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(GND) terminal. The shields must be terminated at the
shields of the incoming and outgoing RS485 leads
Connect 120 OHM,
I/O Board
½ Watt resister between + and – RS485 terminals on the LAST C-More Box.
METHOD B – TERMINATION ACTIVATED AT I/O BOX
Figure 2-8: RS485 (Modbus) Wiring For KC1000 Boilers (Sheet 2 of 2)
MC2: 04/23/13 Page 28 of 144
Do not terminate the shields of the RS485 leads to the ground
NOTE
source ends only. Connect the
together.
GF-131
AERCO Control System (ACS)
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, New York 10913 • Phone: 800-526-0288
OMM-0081_0D
Y2
Y3
Y4
Y1
SW1
A1
I
0
BCM FRONT VIEW
7 6 5 4 3 2 1
Y2
JP2
JP1
T
C
V
JUMPER
SHOWN IN “TERMINATED” (UP) POSITION
MODBUS B (+)
MODBUS A (-)
RS485 Wiring at Boiler BCM of Modulex Boiler(s)
DO NOT terminate the shields at the Boiler end of the RS485 loop.
chain must have the termination jumper

2.7.2 RS485 Wiring for Modulex Series Boilers

RS485 wiring connections are made at the MODBUS terminals of each Boiler’s BCM Module as shown in Figure 2-9. Connect the wiring as shown below:
1. Connect the positive lead to terminal 1 (MODBUS B +) of connector Y2.
2. Connect the negative lead to terminal 2 (MODBUS A -) of connector Y2.
3. Connect the shields of the incoming and outgoing leads together. The RS485 loop shield should only be terminated at the ACS.
4. The last BCM in the daisy­engaged as shown in Figure 2-9.
5. The two ACS bias switches (Figure 2-6) must be activated by placing them in the down position.
MC2: 04/23/13 Page 29 of 144
Figure 2-9: RS485 (Modbus) Wiring For Modulex Series Boilers
GF-131
AERCO Control System (ACS)
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, New York 10913 • Phone: 800-526-0288
OMM-0081_0D
NOTE
turned on. Refer to Section 2.7 of this
termination.
NOTE
be turned to “ON”.

2.8 SAMPLE RS485 (MODBUS) NETWORK DIAGRAMS

Figure 2-10 shows a sample RS485 (Modbus) Network diagram with the ACS connected to
KC1000 or Benchmark Series Boilers equipped with C-More Control Systems. Figure 2-11 shows a similar sample diagram with the ACS connected to Modulex Series Boilers equipped with BCMs and E8 Controllers.
The last C-More slave on the RS485 loop must have its termination resister (TERM) and bias (BIAS1, BIAS2) DIP Switches
manual for details on activating bias and
Figure 2-10: Sample RS485 (Modbus) Network For Benchmark or KC1000 Boilers
The last BCM slave on the RS485 loop must have its termination resister (T) activated. Refer to GF-115C for more information.
The bias switches in the ACS should both
Figure 2-11: Sample RS485 (Modbus) Network For Modulex Series Boilers
MC2: 04/23/13 Page 30 of 144
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