Sierra Max-Trak 180+ Compod Series Instruction Manual

Model 180 + Compod™

Programmable Control Module For

180 Series Digital Mass Flow Meters & Controllers

Instruction Manual

IM- 180 COMPOD

Revision: C, April 2010

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Phone [phone] (800)-866-0200 Fax [phone]

www.sierrainstruments.com

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Phone: [phone] Fax [phone]

Compod™ Instruction Manual IM-COMPOD Rev. C 1

IMPORTANT CUSTOMER NOTICE

Sierra Instruments, Inc. is not liable for any damage or personal injury, whatsoever, resulting from the use of Sierra
Instruments standard mass flow meters or controllers for oxygen gas. You are responsible for determining if this
mass flow meter or controller is appropriate for your oxygen application. You are responsible for cleaning the mass
flow meter or controller to the degree required for your oxygen flow application.

© COPYRIGHT SIERRA INSTRUMENTS 2010

No part of this publication may be copied or distributed, transmitted, transcribed, stored in a retrieval system, or translated
into any human or computer language, in any form or by any means, electronic, mechanical, manual, or otherwise, or
disclosed to third parties without the express written permission of Sierra Instruments. The information contained in this

manual is subject to change without notice

.

TRADEMARKS

Compod™, Smart-Trak®, and Dial-A-Gas™ are trademarks of Sierra Instruments, Inc. Other product and company names
listed in this manual are trademarks or trade names of their respective manufacturers

.

Compod™ Instruction Manual IM-COMPOD Rev. C 2

INTRODUCTION

The Model 180 + Compod™ is a Modbus add-on module for the Sierra Instruments’ Smart-Trak® Model 180 gas flow
measurement and control instruments.

A variety of features enable the integration of the Smart-Trak® into a Modbus network environment. Among these features:

• Access to all vital data

• Totalizer

• Alarm output

• Analog inputs

• Smart-Trak® functionality monitor

SAFETY INFORMATION

Caution and warning statements are used throughout this manual to draw your attention to important information.

Caution!

This statement appears with information that is
important for protecting your equipment and
performance. Read and follow all cautions that
apply to your application

!

!

TIP

TO FULLY UNDERSTAND THE MODEL 180 + COMPOD™ AND ITS FUNCTIONS IT IS ADVISED TO ALSO READ

THE SMART-TRAK® SERIES 180 INSTRUCTION MANUAL

Warning!

This statement appears with information that is
important to protect people and equipment from
damage. Pay very close attention to all warnings
that apply to your application

a

Compod™ Instruction Manual IM-COMPOD Rev. C 3

–

ELECTRICAL CONNECTIONS

All electrical connections are made on the terminal board. There are two screw terminals which give access to input power,
network interface and other options.

PIN CONFIGURATION

Terminal board overview:

Pin layout:

Pin Function Pin Function

1 +24V Power 9 Note 1
2 Ground 10 Note 1
3 Earth 11 RS232-RX (in)
4 Set point input 12 RS232-TX (out)
5 4-20mA output 13 Ground
6 Alarm output 14 RS485
7 Analog channel 1 15 RS485 –B
8 Analog channel 2 16 RS485 Shield

During power-up or reset the Modbus ID pins are scanned. These pins set the Modbus ID code.

ID3 ID2 ID1 ID0 Modbus ID

open open open open Internal ID
open open open closed 1
open open closed open 2
open open closed closed 3

- - - -

closed closed closed closed 15

(Place jumper to enable)

P1

A

Closed

Open

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Note 1: The terminal connections are used for optional interfaces (HART) which can be added. Please contact Sierra
Instruments for more information.

RS485 CONNECTION

CONNECTION

Pin 14 = RS485 – A

Pin 15 = RS485 – B

Pin 16 = RS485 – Shield

THE MODEL 180 + COMPOD™ IS EQUIPPED WITH AN OPTICAL ISOLATED RS485 INTERFACE. DON’T
CONNECT THE RS485 SHIELD TO THE GROUND OF THE POWER SUPPLY UNLESS THE ISOLATED BARRIER

!

ISN’T REQUIRED

GENERAL 2-WIRE TOPOLOGY RS485 NETWORK

The “RS485 – A” (also referred as ‘-‘) is connected with the D0 line. The “RS485 – B” (also referred as ‘+‘) is connected with
the D1 line. The shield is connected to the common line of the network.

Compod™ Instruction Manual IM-COMPOD Rev. C 5

A maximum of 32 devices is authorized on an RS485 system without the need of a repeater.

Cable

It is recommended to use a twisted pair type of cable (reduces radiated and received EMI). Category 5 cables may be used to
a maximum length of 600 meters. To operate at cable lengths of 1000 meter it is advised to use AWG 26 or lower.

Terminator

Reflections in a transmission line can cause communication errors. To minimize the reflection it is required to place
terminator resistors at both ends of the cable. Never place a terminator resistor somewhere along the cable. The use of line
terminators depends on cable lengths and should be determined on site. Typical values for terminator resistors are 120 ohm
(0.5 W).

Line Polarization

In noise environments it may be necessary to polarize the lines to ensure that the receivers stay in a constant state when no
signal is present. The polarization must be implemented at one location for the whole bus. The value for the pull up and pull
down resistors is between 450 and 650 ohms (a higher value permits more devices to be connected to the bus).

ANALOG INPUTS

The analog inputs can be used to connect various transducers (temperature, pressure etc.). Maximum input range is 0-10
Vdc or 0-40 mA. Various options can be set through the Modbus control register (40025).

CONNECTION

Pin 2 = Ground

Pin 7 = Analog input 1

Pin 8 = Analog input 2

V1

V2

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COMMUNICATING

Once the Model 180 + Compod™ is wired to the network and powered up it is time to communicate with it. The settings for
the Modbus interface are as following:

• ID code = 255 (or 1 – 15 depending on the ID pin settings)

• Baud rate = 19200

• Parity = Even

• Number of bits = 8

• Stop bit = 1

• Delay between receiving and transmitting = 2 ms

The above settings are factory defaults and can be changed. Changing the settings can be done through the boot loader or
special registers.

POWER UP

When powering up the red LED (labeled: Net) will light up after 2 seconds indicating the initialization phase. During this time
data is retrieved from the Smart-Trak® and stored into the Model 180 + Compod™ memory. There is no communication
through Modbus possible at this stage.

Once all data is retrieved the red LED goes off and the green LED (labeled: Active) will start blinking as it receives data from
the instrument. Communication through Modbus is possible now.

If the communication with the instrument is lost for some reason, the Compod™ will try to establish it again. During this
phase the Modbus interface will not be active.

The red LED will light up every time a network message is received with the correct ID code.

DATA FORMAT VARIOUS REGISTERS

• 32 bit real: IEEE 754 floating point, low word first

• BCD encoded: hex encoded decimal values f.i. 0x89 = decimal 89

• 8 & 16 bits int: unsigned integer values

• 16 bits ASCII: ASCII encoded characters, high word = 1

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st

character. 0x4944 = “ID”