How to setup MODBUS TCP/IP on a Trolex AirXD

1. Introduction

The following guide is to support the setup of the TX8005 Air XD on an ethernet network. The AirXD supports communications using MODBUS TCP and can be configured to suit the users network

requirements.

2. Ethernet Connection

The connection status of the AIR XD can be viewed by pressing ‘Left’ arrow key when on the PM

value readings screen. The status screen lists the connection type, connection status and

instrument IP address:

3. Ethernet Operating Mode

The AirXD is configured by default to communicate via MODBUS TCP direct to a laptop or server

running a MODBUS client.

4. DHCP Configuration

By default, the instrument is configured to request an IP address using DHCP. This requires that a

DHCP server is also on the network that can assign the IP address. Firewall settings must allow

outgoing traffic on selected port numbers. Note: the MODBUS TCP communicates over ‘Port 502’

By using the dynamic IP assignment option, this prevents the instrument from IP address clashes

where it may hold the same IP address as another device. It also allows for minimum configuration

of the instrument before install, however the device could be assigned different IP addresses on

each power cycle or on address lease timeouts which may prevent the MODBUS TCP client from

communicating without further manual changes.

One workaround to prevent a changing IP address is to change router/DHCP server settings to

reserve an IP address for the MAC address of the instrument.

Example Network Setup

5. Static IP Configuration

For applications where the Air XD requires constant access to the MODBUS TCP client server or

applications where a DHCP server is not available on the network, the use of a static IP is

recommended. To set up the Air XD to use a static IP, use the following steps:

• Change Static IP address of the instrument to its desired value by navigating to the IP settings menu as shown below:

• Enter the Subnet Mask.
• Enter the Gateway address (if applicable)
• Change the assignment type to static, the instrument will now have the inputted IP address on the network

To check the IP address of the instrument either go to the Network status screen or hold the ‘left’

key while the particulate data is displayed.

Example Network Setup

6. Troubleshooting

6.1 Check Status

If communication cannot be established with the Air XD, check the network status screen for

information on the unit’s connection status:

If the unit is in the ready or connected state, the instrument is ok and can communicate on the

network, the communication problem is likely to be elsewhere on the network.

The error state is entered if the Air XD has failed to set up the MODBUS TCP server. Power cycle

the unit to retry the initialisation. If the unit is entering this state permanently/frequently, please

contact Trolex Support.

If the Air XD is in the offline state, check the connection of the Ethernet cables and power to any

network switches or DHCP servers (if using DHCP)

6.2 Checking Connection with Air XD

Communication to the Air XD can be tested without running a MODBUS TCP client and instead

using the windows command line. Once the Air XD is reporting an IP address either using DHCP or

Static IP, open the command line and enter the command ‘ping’ followed by the IP address of the

instrument. If the device can communicate on the network, then the terminal shall receive a reply

as shown below:

6.3 Cannot communicate with terminal/laptop

If the ping command fails to return a response (timeout). Then perform the following checks to the

network:

• If using an Isolated LAN network, ensure the laptop/terminal is also using a static IP. On windows machines communications are disabled if the unit has no IP address
• Check cable connections & power to any switches, router or DHCP server
• Ensure Laptop/Terminal is operating on the same network as the instrument

6.4 Cannot communicate on network also running DHCP server

If using dynamic IP allocation, check firewall settings to ensure communication is allowed on Port

502.

If using static IP assignment, check that no other device is allocated the same IP address of the

instrument.