AERCO AC-106 Communication Manual

Instruction
No.

AERCO INTERNATIONAL, Inc., Northvale, New Jersey 07647 USA

AC-106

®

MODBUS

Communication Manual

for

ELECTRONIC CONTROL SYSTEM

(ECS)

Used to Interface AERCO Equipment

to Building Automation Systems

Modbus® is a registered trademark of AEG Modicon

REVISED 7/28/10

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ii

ELECTRONIC CONTROL SYSTEM COMMUNICATION INTERFACE

TABLE OF CONTENTS

Title Page

1. INTRODUCTION 1

2. COMMUNICATION BOARD 1

3. MODBUS COMMUNICATION SIGNAL CONNECTIONS 1

4. MODBUS COMMUNICATION INFORMATION 2
5 CHANGING COMMUNICATION ADDRESSES ON THE AERCO EUROTHERM
TEMPERATURE CONTROLLER 4

6. REFERENCED DOCUMENTS 6

7. INTERFACING THE ECS WITH A BUILDING’S BAS/EMS 6

8. ALARMS 7

9. CLEARING HARDWARE ERROR (HW.ER) DISPLAY 8

LIST OF FIGURES

1. Temperature Controller (Eurotherm 2408) Terminal Connection Diagram 2

LIST OF TABLES

1 MODBUS Communication Signal Connections 2

2. Eurotherm Series 2400 Controller MODBUS Points 3
3 AERCO Electronic Control System (ECS) Point Definitions 6

4. Process Alarms 7

5. Diagnostic Alarms 7

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iv

AC-106 INSTRUCTIONS - ECS COMMUNICATIONS

ELECTRONIC CONTROL SYSTEM COMMUNICATION INTERFACE

1. INTRODUCTION

The Electronic Control System (ECS), used on AERCO indirect fired water heaters, can be ordered with a
MODBUS® Communication Option, which will permit it to be controlled by an external Energy
Management System (EMS), Building Automation System (BAS), or a computer supplied by others.

2. COMMUNICATION BOARD

The Communication Board provides the MODBUS interface between any of the possible external control
systems and the ECS. The Temperature Controller (Eurotherm 2408) used in the ECS can be optionally
equipped with a Communication Board which can be connected to external control systems utilizing either
an RS232 or RS485 MODBUS communication interface. The corresponding part numbers for the
alternative MODBUS Communication Boards are as follows:

PART NUMBER DESCRIPTION

64009-1 RS232 COMMUNICATION BOARD

64009-2 RS485 COMMUNICATION BOARD

3. MODBUS COMMUNICATION SIGNAL CONNECTIONS

CAUTION

DO NOT route MODBUS communication wiring in the same conduit as power wiring.
Attempting to do so may result in excessive noise on the signal lines. Also, ensure that
the RS232 or RS485 signal cable connections do not exceed the following lengths:

CABLE TYPE

RS232 50 feet

RS485 4,000 feet

To implement ECS MODBUS control, connect the cable leads from the external controller to the
Temperature Controller as instructed in Table 1.

• Refer to the Temperature Controller (Eurotherm 2408) pinouts shown in Figure 1 to locate the
required terminals.

• Refer to Table 2 Eurotherm Series 2400 Controller MODBUS Points for a listing of active
MODBUS data addresses for the 2408 Controller.

• The Eurotherm documents referenced on page 3 provide additional communication information
related to MODBUS.

MAXIMUM LENGTH

NOTE

AERCO recommends that shielded, twisted-pair cable be used for communication wiring.
Examples of suitable wiring are: Belden 9841, 8761, 3105A, or equivalent.

1

Table 1. MODBUS Communication Signal Connections

2408 TEMPERATURE

CONTROLLER

SIGNAL

PIN NO.

NAME

RS232/9-PIN RS232/25-PIN RS485

SIGNAL

NAME

COMPUTER CONTROL CABLE

PIN NO. PIN NO. PIN NO.

GROUND HD GROUND 5 7 GROUND

RECEIVE HE TRANSMIT 3 2 A-

TRANSMIT HF RECEIVE 2 3 B+

2408 CONTROLLER

1A

1B

1C

1D

2A

2B

2C

2D

3A

3B

3C

3D

HA

HB

HC

HD

HE

HF

JA

JB

JC

JD

JE

JF

L

N

LA

LB

LC

AA

AB

AC

VI

V+

V-

In1

In2

C

Figure 1. Temperature Controller (Eurotherm 2408) Terminal Connection Diagram

4. MODBUS COMMUNICATION INFORMATION

The Eurotherm 2400 Controller supports the MODBUS RTU mode of transmission. The default settings
are as follows:

• 9600 baud rate

• One start bit

• Eight data bits

• One stop bit

• No parity

2

MODBUS

Address

Data

Table 2. Eurotherm Series 2400 Controller MODBUS Points

Menu

Item

Menu Item

Description

Units &

Range

Default/Comments

Register

Type

Ref. 1

Comm.

Guide

5 w.SP Setpoint 40-205°F 140°F, Address to

read value

24 SP 1 Setpoint 40-205°F 140°F, Address to

change value

1 Top

Value

133 LoGH Peak Temp 40-205°F Resets on Power

135 LoGA Average

134 LoGL Low Temp 40-205°F Resets on Power

13 (set)

74 (status,

0 = safe

1 = alarm)

14 (set)

74 (status,

0 = safe

AL 1 Over Temp

AL 2

(FSH)

Outlet Temp 40-205°F Same value as front

display

Loss

40-205°F Resets on Power

Temp

Alarm

Full Scale
High Alarm

40-205°F 20°F above

205°F 205 ° F

Loss

Loss

setpoint; Alarm
Type 17: Deviation
High

Alarm Type 2: Full
Scale High

Read

Only

Write 5-11

Read

Only

Read

Only

Read

Only

Read

Only

Read

Only

Read

Only

5-4

5-3

5-15

5-15

5-15

5-7

5-20

5-7

5-20

1= alarm)

258 Sbr Feedback

Sensor Break

289 Li 1 Feedback

Sensor Temp

290 Li 2 Flow GPM Read

3 OP Control

Output Signal

26 RmSet

pt

Remote
Setpoint

Status:

0: Good

1: Failed

40-180°F Sensor input to

% Correlates to valve

(40 to 180)
°F

Denotes Feedback
Sensor
Failure/Open Circuit

controller, same as
display temp.

position

Holding

Read

Only

Read

Only

Only

Read

Only

3

5-18

5-14

5-14

5-4

5. CHANGING COMMUNICATION ADDRESSES ON THE AERCO
EUROTHERM TEMPERATURE CONTROLLER

To change the modbus address:

The address is defaulted to 1 from
the factory. Refer to the Button map
below for all panel navigation
instructions.

1. Page to the ACCS list and
Scroll down the list to codE.

2. Enter 24 using the Up Arrow.

The number will display and flash
PASS.

3. Scroll to Goto (current value is OPEr) and use the
Down Arrow to enter a value of Full

confirmed by the flashing of the lower display
momentarily off and then on.

Button Map

Page

4. Go to the home screen by pressing the Page
and Scroll buttons at the same time.

Scroll

Down
Arrow

. The entry is

Up

Arrow

4

5. Page to the cmS list

6. Scroll to the Addr screen

7. Use the Up Arrow to select

the desired address number.

8. Go to the home screen by

pressing the Page and
Scroll buttons at the same

time.

9. Page to the ACCS List and

change the code to anything

other than 24 and the codE

number you entered will
flash off and then on to 0 to
confirm that access is now
set to the OPEr level and is
safe to return to use.

10.Confirm that the Addr is set
properly by pressing Page button

until the cmS list is displayed and

Scroll to Addr. If the value is

correct you are done, if not
please repeat the steps again.

5

6. REFERENCE DOCUMENTS

1. Eurotherm 2000 Series Communications Handbook, # HA026230

2. Eurotherm 2404/2408 Control Setpoint Programmer Installation and Operation

Handbook, # HA025132

7. INTERFACING THE ECS WITH A BUILDING BAS/EMS

The ECS may be interfaced with a building’s Building Automation System (BAS) or Energy
Management System (EMS). Table 3 below shows the Modbus data addresses both for the
BAS/EMS and the AERCO ECS.

Table 3. AERCO Electronic Control System (ECS) Point Definitions

Equip. Point Name

Electric Valve (ECS)

01-Cntl Output
Signal 30004

02-Setpoint 30006 w.SP (Setpoint) Input 0x0005 / 5 °F (40 to 180)

03-RmSetpt 40027

04-Outlet Temp 30002

05-FBk Sensor
Temp 30290

06-Over Temp Alarm 30075

BAS Modbus

Data Addr

AC-106 Point

Name

OP (Control
Output Signal) Input 0x0003 / 3 % (0 to 100)

Remote Input
Comms Access
parameter(Setpoi
nt) Holding 0x001A / 26 °F (40 to 180)

Top Value (Outlet
Temp) Input 0x0001 / 1 °F (40 to 205)

Li1 (Feedback
Sensor Temp) Input 0x0121 / 289 °F (40 to 180)

AL 1 (Over Temp
Alarm) Input 0x004A / 74

Reg.

Type

Modbus Data

Addr (Hex/Dec.) Units (Range)

Enum (0,1) 0 = Safe, 1 =
Alarm

07-Flow Rate 30291 Li2 (Flow) Input 0x0122 / 290 GPM

IMPORTANT

All Modbus addresses specified in this manual are written generically in
hexadecimal/decimal format. However, many Building Automation Systems utilize
another form of addressing where:

• 40001 is added to the generic address for a Holding Register
address.

• 30001 is added to the generic address for an Input Register
address.

Check the addressing scheme being used by the BAS interfaced to the XPC Gateway.

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8. ALARMS

Table 4. Process Alarms

DISPLAY MEANING

_FSL*
_FSH*
_dEu*
_dHi*
_dLo*

PV Full Scale Low Alarm.

PV Full Scale High Alarm.

PV Deviation Band Alarm

PV Deviation High Alarm

PV Deviation Low Alarm

Table 5. Diagnostic Alarms

DISPLAY MEANING WHAT TO DO`

EE.Er Electrically Erasable Memory Error:

The value of an operator, or
configuration, parameter has been
corrupted.

S.br

Sensor Break
Input sensor is unreliable or the
input signal is out of range.

This fault will automatically take you into
Configuration level. Check all of the
configuration parameters before returning
to Operator level. Once in Operator level,
check all of the operator parameters
before resuming normal operation. If the
fault persists, or occurs frequently,
contact your supplier

Check that the sensor is correctly
connected

L.br

Hw.Er

no.io

rmt.F

LLLL
HHHH
Err1

Err2
Err3

Loop Break
The feedback loop is open circuit

Hardware Error
Indication that a module is of the
wrong type, missing, or faulty.

No I/O
None of the expected I/O items are
installed

Check that the heating and cooling
circuits are working properly

Check to ensure that the correct items
are installed. See page A-4 for procedure
to clear the Hardware Error.

This error message normally occurs
when pre-configuring a controller without
installing any of the required I/O
modules.

Remote input failure.
The remote DC input is open or

Check for open or short circuit wiring on
the remote DC input.

shorted

Out of range low reading Check the value of the input

Out of range high reading Check the value of the input

Error 1: ROM self-test fail Return Controller for repair

Error 2: RAM self-test fail Return Controller for repair

Error 3: Watchdog fail Return Controller for repair

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AC-106 INSTRUCTIONS - ECS COMMUNICATIONS

Err4

Error 4: Keyboard failure. Stuck
button or button was pressed

Switch power off and then on, without
touching any of the controller buttons

during power-up

Err5

Error 5: Faulty internal
communication

Check printed circuit board
interconnections. If the fault cannot be
cleared, return the controller for repair.

Err6

Digital filter chip faulty or loose

Return Controller for repair

board inside controller

Err7
Err8

PV ID failure Return Controller for repair

Module 1 ID failure Faulty or loose module, or isolation

problem

Err9

Module 2 ID failure Faulty or loose module, or isolation

problem

ErrA

Module 3 ID failure Faulty or loose module, or isolation

problem

dCF

DC output failure Return Controller for repair

9. CLEARING HARDWARE ERROR (HW.ER) DISPLAY

To clear a Hardware Error and reset the Temperature Controller, proceed as follows:

1. Simultaneously press the Page (

) and Scroll ( ) buttons on the Temperature Controller.

2. Using the Up (▲) arrow button, change the password to “8”.

3. Simultaneously press the Page (

) and Scroll ( ) buttons again and observe the

Temperature Controller display. The top line will display “8” and the bottom line will display “NO”.

4. Press the Up (▲) arrow button to toggle the display from “NO” to “YES”.

5. Simultaneously press the Page (

) and Scroll ( ) buttons to “Reset” the Temperature

Controller and clear the Hardware Error.

8