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Modbus Organization Newsletter, March 2012

Going to Hannover Fair?

This year from April 23 to 27,

Hannover Fair opens its doors to

visitors from around the world.

Many Modbus Organization mem-

bers are represented at the fair and

are available to answer questions

about their offerings. For your convenience, here

is a listing of members currently planning on

showing at Hannover 2012:



Belden Electronics: Hall 27, Stand G34

connectBlue: Hall 8, Stand D37

eWon: Hall 8, Stand D31

Fieldbus International, Fint: Hall 9, Stand

D05

Grundfos: Hall 14, Stand L09

HMS Industrial Networks: Hall 9, Stand D05

JVL Industri Elektronik: Hall 15, Stand H39

Kepware Technologies: Hall 9, Stand A15

Matrikon: Hall 9, Stand A15

MKS Instruments: Hall 17, Stand E07

Phoenix Contact: Hall 8, Stand D27

Schneider Electric: Hall 11, Stand C50

Softing AG: Hall 9, Booth C33L

Trebing & Himstedt Prozeßautomation: Hall

9, Stand D05



Modbus RTU Video

John Rinaldi, founder of Modbus Organization

member company

Real Time Automation,

presents a

brief and informative video

all about

Modbus RTU.

Questions about RS-232 vs RS-485? Confused

about registers? Check out John’s explanations

and examples to beef up your understanding.

New Additions to Modbus

Resources Page

The Modbus Organization’s Technical Re-

sources page

list of resources

for Modbus devel-

opers and users continues to grow.

New and updated listings include:



Ananas — the Modbus TCP

diagnostic tool for Windows

has been upgraded to now

include a 64-bit version.

WinModbus — a Windows

Modbus Server simulator

supporting Modbus RTU

and TCP, with a free trial version available

for download

CAS Modbus RTU Parser — analyzes Mod-

bus messages when you type in a string of

hex bytes. The parser will break the mes-

sage out showing you destination, func-

tion,and data.

CAS Modbus Explorer — attempts to con-

nect to RTU devices using various permuta-

tions of baud, data and stop and data point

until it makes a connection.

Modbus Security

Modbus Organization member company Byres

Security’s most recent blog post discusses Deep

Packet Inspection (DPI) .

this blog entry,

Eric Byres talks about use of

the new Tofino™ HMRF Honeywell Modbus

Read-only Firewall.



News about the World’s Most Popular Protocol

Member News

device data of interest to internal

registers in the Client. The pro-

gram accesses these registers

directly for reads and writes, as

if they were native to the

controller.

Each 5300 communications port

can be configured independently

for either Client or Server opera-

tion. This means the 5300 can be

used as both a Client on one net-

work and a Server on another at

the same time.

Member News

Founded in 1975,

Control

Technology Corp.

has a long

history of providing innovative

automation solutions to its

customer base. CTC recently

released an upgraded CPU for its

5300 series controllers. The 5300

controller now boasts full Modbus

capability as a Client or Server

device, or both.

CTC’s 5300 supports Modbus

Server commands as built-in

functions on its Ethernet, RS-

232, and RS-485 ports. Users

assign the IP Address for

Ethernet or node address for

RTU in the set up configuration.

The controller handles the rest.

For a Modbus Client, a

connection block is set up in the

5300 program to configure

Modbus Server devices based on

IP Address for Ethernet or node

address for RTU. This block lets

users set unique poll rates for

each Server device, and map

With headquarters in Germany

and a North American

subsidiary,

Softing Industrial

Automation

is a premier

provider of industrial

communication products and

technologies for manufacturing

and process automation.

With its focus on industrial

communication solutions and

products, Softing supports a

variety of relevant technologies.

Softing’s

Modbus TCP/OPC

Server

enables fast, convenient

access to the I/O registers and

coils of any Modbus devices via

an Ethernet interface. The

server supports all OPC client-

enabled software, including

Citect, GE Cimplicity, GE Fanuc

iFix, Iconics Genesis, Rockwell

RSView, Siemens WinCC and

Wonderware InTouch.

Model 5300 Programmable

Automation Controller

Modbus Newsletter

This is the newsletter of the Modbus

Organization, the international nonprofit

organization devoted to the evolution and

support of the Modbus protocols.

The Modbus Organization Mission

The Modbus Organization, Inc. is a group of

independent users and suppliers of automation

devices that seeks to drive the adoption of the

Modbus communication protocol suite and the

evolution to address architectures for distributed

automation systems across multiple market

segments. Modbus Organization also provides the

infrastructure to obtain and share information about

the protocols, their application, and certification to

simplify implementation by users resulting in

reduced costs.

For more information about membership and

other services, please refer to our website:

www.modbus.org

Newsletter Editor:

Lenore Tracey (lenore@modbus.org)

Modbus Organization, Inc.

PO Box 628

Hopkinton, MA 01748 USA

ph +1-508-435-7170

Member News

The Stichthage Building Reconstruction, The Hague

If you visit The Hague, the third

largest city in The Netherlands,

by train, the first building you

see is the Stichthage — a multi-

functional building integrated

into the central railway station.

It was built in the early 1970s as

a typical steel-concrete building

with glass facade. It is 60 m high

and it has 15 floors hosting

offices, shops, and restaurants;

floors one and two merge with

the railway station hall.

After 38 years of operation, the

building was reconstructed in

2011. As with many buildins of

similar vintage, the main reason

for this was high energy

consumption.

The rooms were heated by heat

exchangers situated under the

windows, controlled by

Honeywell R7455A room

controllers. These were

controllers with individual

setpoint correction and presence

and window contact inputs (not

used here, as the windows could

not be opened). The heat

exchangers have separate

heating and cooling hydraulic

circuits. The communication was

used for monitoring only.

With the reconstruction, the

designers required controllers

with outputs for heating and

cooling, and a separate

temperature sensor to be placed

in front of the heat exchanger as

a limiting supply air sensor. This

solution is quite common at fan-

coils, but there was a constant air

volume system here with air

supply from central air handling

units.

A standard fan-coil controller

would be rather expensive,

because the relay

outputs would not be

used.

After briefly researching

the market, the local

distributor for

Domat

Control System

controllers requested

development of a specific

controller to fit the application at

reasonable price.

The resulting UC230 controller is

based on the design of the floor

heating controller UC300, which

also has an external Pt1000

temperature sensor. One extra

triac PWM output, one binary

window contact input, and

firmware adaptation had to be

added. The controlled variable is

the internal sensor temperature,

external sensor temperature, or

average temperature of those two

sensors.

Thanks to Modbus RTU, it was

no problem to integrate the room

controllers to the building control

and management system.

The communication is used for

monitoring and temperature

control. Controllers are grouped

by floors and floor parts

according to usage scenarios and

tenants, each group having its

own time schedule. This brings

significant energy savings.

The development of the custom

controllers was completed

quickly, and the first samples,

together with the bases with

terminals, were supplied in May

2011. Then it was possible to

install the cabling and to connect

the terminals in advance, even

before the controllers were

supplied. Subsequent installation

simply required the controller

body to be snapped onto the base

with the terminals.

A total of 693 controllers were

installed in the building, on

floors two to 13. Each floor is

linked with a separate bus to its

primary DDC process station.

After the night depression, all

daily setpoint corrections are

returned to the original values

through a central command. The

result of these measures is re-

classification of the building

efficiency from the highest

rating— G — to D+, and, of

course, reduced energy bills for

the tenants.

It was also important to the

customer that Domat Control

System offer free addressing and

preconfiguration of the

controllers so that they could be

pre-labeled with their addresses

and corresponding room

numbers. The tables with

addresses and room numbering

were supplied by the designer in

advance, so the controllers did

not have to be addressed on site,

which saved time and reduced

the possibility of faulty

placement.

Primary heating and cooling

controls were supplied by Priva.

Member News

Over 150 JetBox 9300 computers

were installed as the base of the

data acquisition system from

main substation plant assets. By

integrating LAN, Digital I/O and

serial ports into a single compact

box, the JetBox 9300 computer

fits easily in small spaces, saving

physical media costs.

The stored data on the SD card is

then sent to the system using the

Ethernet ports.

To manage the network easily

and efficiently, the system inte-

grator initially chose to use Jet-

Box for the its use as a Modbus-

to-SNMP gateway; the JetBox

9300 enabled engineers to check

and modify processes at the local

sites using the Modbus protocol,

while IT staff in control rooms

use SNMP to get device data and

perform network management.

Member News

Korenix Optimizes Substation SCADA System ...

A power distribution company

seeking to build a cost-efficient

and reliable SCADA system se-

lected the Korenix JetBox 9300

for its application. The JetBox

9300 is a Modbus-to-SNMP gate-

way, and combines multiple in-

terfaces and the Linux operating

system.

An enhanced, high-quality

SCADA solution is essential to

ensure effective operation of a

utility’s critical and costly assets.

Use of advanced technologies,

data transmission reliability and

lower costs are some of the basic

requirements for building the

interactive smart grid of the fu-

ture.

Heavy-duty substation environ-

ments demand rugged systems

that will operate without disrup-

tion under the most severe condi-

tions.

The JetBox 9300 is designed

with reliable RISC processor to

provide the stability and reliabil-

ity required for real-time utility

control. The Linux SDK is avail-

able for users to develop pro-

grammable front-end controller

applications. With the Korenix

Auto-Run customization setting

on SD card, users can configure

their own Linux commands and

automatically run specific appli-

cations.

JetBox’s rugged, fanless design

allows users to install the units

in harsh power distribution sites,

while preserving network per-

formance and preventing connec-

tivity loss — to ensure stable,

reliable and efficient communica-

tion in power substations.

Advertise on the

Modbus.org Website

With

a half million pages served to

almost 30,000 unique visitors each

month,

what better place to advertise

your Modbus devices and software ?

for a rate sheet. A special

member's discount makes banner

advertising an even better deal when

you join the Modbus Organization.

Member News

Modbus Discussion

Member News

Modbus Discussion

Q&A from the Modbus Discussion Forum...

How to connect two Modbus RTU Clients...

On January 18, jianjian posed

the following question:

I have to connect ABB DCS with

Emerson DCS. We chose Modbus

RTU for this communication. But

the problem is now two DCS

hardware modules are set as Cli-

ent. It cannot change. Is there

any equipment that can be used

to help the two Modbus RTU Cli-

ents communicate?

The ABB module can only use

Modbus RTU, but Emerson can

use Modbus RTU or TCP. So, can

I have solution to connect Mod-

bus RTU with Modbus TCP with

both sides as Client?

Thanks for your help!

Richard suggested:

Set up a gateway with two Mod-

bus RTU Servers; you can do this

with a FieldServer gateway.

Jerry Miille offered:

You could use our Omnii-Comm

product for this application. Con-

ceptually, you would define a

block of Modbus Holding Regis-

ters that can be written to or

read from by each Modbus Client

at any time. You may contact me

off list if you need additional in-

formation (713-472-6272).

Darrin Hansen also had a so-

lution:

The ICC XLTR-1000 has two RS-

485 ports, each of which can be

configured with Modbus RTU

Server drivers (thereby allowing

two Client devices to exchange

information, with the gateway

acting as an intermediary).

If you are looking to convert be-

tween Modbus TCP and RTU,

then the ETH-1000 is from the

same product family, but re-

places one of the RS-485 ports

with an Ethernet port. One of the

drivers that can be configured on

the Ethernet port as Modbus

TCP server, so again you can ex-

change information between two

Clients through the gateway (in

this case, one RTU Client and

one TCP Client).

Lynn Linse summed it up:

I knew there would be many an-

swers :)

What you must do is buy one of

the above devices, then have one

of your Client “write” the data

share to this device (you can also

just buy a small Modbus PLC

with two serial ports).

Then the second Client reads

from the shared Server. Just be

careful how the second Client

“validates” that the data is valid.

For example, if the link between

first Client and device fails, the

data will go stale and might fool

the second Client.

All of the devices above should

offer a solution to this directly

(they might include a “health-

status register,” or even mimic a

dead Server with time-outs —

check with the vendor as to how

this is done.

If you use a small PLC, you'll

need to design your own scheme.

For example, have the second

Client write a value 1 to some

ent reset it to 0 any time it up-

dates the PLC. Thus, if the reg-

ister remains the value 1, then

the first Client is no longer up-

dating the data.

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