Overview

The Modbus IP data source is used to gather data from Modbus equipment accessible over an I/P network. Equipment can be in a local network or intranet, or could also be anywhere in the internet. This is a polling data source.

Configuration

Every data source requires a Name, which can be any description. The Update period determines how often the Modbus equipment is polled for data. The Timeout and Retries fields determine the system behaviour in the case of a polling failure. The data source waits the given number of timeout milliseconds for a response from the equipment. If it is not received the request will be retried the given number of times.

Three Transport types are supported. See the documentation for you equipment to determine which setting can be used.

The Host and Port settings determine how to find the Modbus equipment on the network. The host can be a domain name or an IP address.

Node scanning

Networks can be scanned for slave nodes using the scan utility. This feature iterates from slave id 1 to 240, sending each a ReadExceptionStatus (function code 7). If a response is received (using the given timeout and retries settings), the node is considered available. Note that not all equipment supports this function code, so false negatives are possible.