Oldham iTrans 2 User Manual

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IMPORTANT: When commissioning master and slave units on a ModBus
network, it is critical to ensure that every device on the ModBus network
must have a unique address. Otherwise, abnormal behavior of the entire
serial bus can occur.
Sample Gas Reading via ModBus Network
To get a gas reading for Channel 1, you must read register 40102. This
register holds the gas reading in ppm.
Example: Gas reading of 5 ppm = register value of $0005.
Example: Gas reading of 20.9% = register value of $0209.
For Channel 2 you can access the gas reading by looking at register 40202.
For a full list of ModBus commands and registers that are accessible on the
, refer to the next section.
ModBus Register List
ModBus register addresses are provided in Table 6-1.
Addr
Inst
R/W
Host
R/W
Range
Description
40101
R/W
R/W
MSB = $01 to
$FF
LSB = $01 to
$F7
Sensor Type
Holds the sensor instrument type code
and ModBus address. The most
significant byte (MSB) holds a value
indicating the type of instrument (see
below). The least significant byte (LSB)
holds a value which is the ModBus
address of the sensor.
MSB = Instrument type code $01 to $FF
$03 = IR (infrared)
$04 = TOX (toxic)
$05 = OXY (oxygen)
$06 = AAW (toxic)
$07 = CAT (catalytic)
LSB = MODBUS sensor address $01 to
$F7 (1 to 247)
40102
W
R
$0000 to $FFFF
Gas Reading
Holds the gas reading in ppm or percent
depending upon the sensor in the
instrument. The range is from $0000 to
$FFFF and represents a signed decimal
value range from -32768 to +32767.

Oldham iTrans 2 Specifications

General

Enclosure	Aluminum or Stainless Steel
Target Gas	Combustibles, H2S, CO, O2
Output	4-20 mA, HART
Display	LCD
Hazardous Area Approval	ATEX, IECEx
Operating Humidity	0-99% RH (non-condensing)
Resolution	Varies by gas
Response Time	< 30 seconds
Protection Rating	IP66
Measurement Range	Varies by gas. Combustibles: 0-100% LEL, H2S: 0-100 ppm, CO: 0-500 ppm, O2: 0-25% vol, NH3: 0-100 ppm, Cl2: 0-10 ppm, HCN: 0-30 ppm, NO2: 0-10 ppm, SO2: 0-20 ppm

Summary

Chapter 1 | Overview

Overview of the Gas Monitor

Describes the iTRANS-2 fixed gas monitor, its capabilities, and features.

Specifications

Chapter 2 | Hardware Overview

Main Electronics Unit (Housing)

Sensor

Inputs – Intrusive and Non-Intrusive

Electronics Modules

Chapter 3 | Installation

Installation Considerations

Chapter 4 | System Wiring

Wiring Preparation

Alarm Relay Wiring

Details how to connect control wires to the relay terminals for alarm and fault signals.

Power and Output Wiring

Explains how to connect power supply and 4-20 mA output signals to connector J1.

Sensor Wiring

Describes connecting sensor wires to connector J3, including wire color coding.

Digital ModBus RTU Interface Wiring

Covers connecting the ModBus interface to digital control systems, PLCs, or HMIs.

Chapter 5 | Operation

Normal Operating Mode

Programming Mode Overview

Introduces the two programming modes (non-intrusive and push-button) and their functions.

Programming Mode – Non-intrusive Operation

Explains how to use a magnetic wand for configuration tasks like sensor type, zeroing, and calibration.

Zeroing

Explains the process of zeroing the instrument using keypad or magnetic wand.

Calibration

Details the process of calibrating the instrument using keypad or magnetic wand.

Changing Span Gas Concentration

Explains how to set the span gas concentration for calibration.

Programming Mode – Push Button Operation

Describes how to access programming options using physical keys after entering a password.

Entering Programming Mode and Selecting a Channel

Set Low Alarm

Details how to set the low alarm threshold for a channel.

Set High Alarm

Details how to set the high alarm threshold for a channel.

4-20 mA Analog Output Range

Chapter 6 | Modbus Interface

Sample Gas Reading via ModBus Network

Explains how to read gas readings from Channel 1 and Channel 2 via the ModBus network.

ModBus Register List

Provides a detailed list of ModBus registers, their addresses, and descriptions.

Chapter 7 | Maintenance

Sensor Replacement

Provides instructions for qualified personnel to replace a sensor.

Zero and Calibration

Details the methods for zeroing and calibrating the instrument.

Chapter 8 | Troubleshooting

Diagnosing Common Problems

Presents common symptoms, their potential problems, and solutions in a table format.

Fault Codes

Chapter 9 | Warranty

Appendix A | HART Interface

Electronics Modules

System Wiring

Power and Output Wiring

HART 4-20mA Wiring

Operation

Calibration and Zeroing Modes

Fault Mode

Open Loop Condition

Electronic Device Descriptor (EDD)

Read Commands

Write Commands

Operation Commands