Application Note: Networking Remote Gas Detectors with Ethernet I/O

Defining the Problem:

In a wastewater treatment plant, remotely mounted gas detectors monitoring Methane CH4 (ceiling), Oxygen O2 (6 ft high) and Hydrogen Sulfide H2S (floor) have analogue outputs. The gas levels need to be saved to chart recorders located in a control room a long distance away in the plant. To save on the cost of running copper twisted pair wires, we would like to network the analogue outputs for transmission over the Ethernet infrastructure.

This application note was provided by our valued supplier Acromag.

System Requirements:

A ControlLogix PLC in the control room can communicate using Ethernet/IP protocol. The Ethernet remote I/O will accept 4 – 20mA inputs from the gas detectors and convert to Ethernet/IP. The PLC will output 4 – 20mA to the chart recorders nearby. Also, the hazardous area requires Class 1 Div 2 instruments.

Implementing the Solution:	Featured Products:
1. In the USB configured XT software, set the IP address, network parameters and input scaling.	• XT1212-000
2. Configure the PLC with Acromag’s ControlLogix application note. This document includes instructions for RSLogix 5000 and RSLinx.
3. With the XT1212-000 software and inputs wired, poll the module and check the measurements using the test page. 4. Validate the Ethernet/IP communications with an Ethernet connection between the XT and the PLC.

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Why Acromag: 

The XT series of Remote I/O has Class 1 Div 2 ratings for hazardous locations where the Gas Detectors are installed. With simple software configuration and an application note detailing the PLC configuration, installation and testing are easily accomplished.

For further information on the Acromag Embedded Board Products in Australia and New Zealand, please contact Metromatics +61 7 3868 4255 or sales@metromatics.com.au  Outside this area, please contact Acromag directly on sales@acromag.com

Application Note on how to provide a reliable way to communicate with multiple distant locations

Take a look as our supplier Acromag illustrates how their BusWorks XT Series Ethernet I/O modules provide a reliable, simple way to communicate with multiple distant locations.

With Acromag's i2o® peer-to-peer communication on the XT1111 Modbus/TCP discrete I/O module, one signal from the central control room PLC can be split and re-transmitted to many remote sites at the same time.

This document illustrates using Acromag's BusWorks® XT Ethernet I/O modules to split one signal from a central control room PLC and control multiple remote locations using Ethernet protocol.

Defining the Problem:

A customer has multiple remote locations linked over an Ethernet network, each requiring discrete outputs. They all need to be sent the same communication signal at the same time.

System Requirements:

• All remote sites need to be controlled simultaneously from one central control room via Ethernet protocol

Implementing the Solution:	Featured Products:
1. Set up the Ethernet communication between master PLC device and the BusWorks XT discrete I/O modules (XT1111)	• 16-Channel Discrete I/O, Modbus/TCP XT1111-000
2. Connect the field instruments and verify input status using the software test & polling feature	• 16-Channel Discrete I/O, with Counter/Timers 989EN-4C16
3. Program the BAS with the remote I/O network parameters and Modbus registers.	• Software Interface Package XT-SIP

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Why Acromag: 

Our BusWorks XT Modbus/TCP remote I/O modules include a peer-to-peer feature known as i2o, where two or more slaves can talk to each other without requiring a master. With i2o communication, one signal from the PLC is split by the XT1111 modules and sent to multiple locations. The XT1111 automatically re-transmits the discrete level to each 989EN module's IP address, thus reproducing the status of the original PLC input. 

For further information on the Acromag BusWorks XT Products, please contact Metromatics on +61 73868 4255 or sales@metromatics.com.au