User - Modbus

Introduction

This page covers the Modbus configuration. This link has more information regarding the Modbus Protocol: https://modbus.org/specs.php.

We can inform clients using the Modbus over TCP Protocol, which links the radar to a client, and can trigger alarms. This works in conjunction with the SafeGuard™ Lite application. This is an optional feature that is subject to its own software licence.

Contents

Modbus

Open

Modbus Mode

This is the data output mode.

Open

None: Both Modbus and Relay output are disabled

Master: The radar will poll other devices that are operating as a slave.

Modbus Address: This is the IP Address of the slave.
Port: This is the TCP port used by Modbus in order to connect to the slave.
Health Offset: The health register offset used by Modbus.

Slave: The radar acts as a server and makes alarm data available to the Modbus master.

Port: This is the port used by Modbus in order to connect to the slave.
Health Offset: This is the register offset used by Modbus.

Relay: The radar will output nav mode area alarms via a Relay unit instead of using Modbus.

Heartbeat Period: When the radar has SafeGuard enabled, alarms can be output over Modbus. Additionally, the radar will update a 'heartbeat' count so that other devices on the Modbus can identify if the radar is working correctly.

The heartbeat is in the form of an incrementing count. The heartbeat update rate can be selected via Vertex to be either 1Hz, 4Hz, 8Hz or 16Hz. The default value is 4Hz, which we generally recommend.

This allows customers with systems that require a faster rate-of-response to check the heartbeat more frequently.

Heartbeat Watchdog: Modbus Watchdog provides an additional level of connectivity robustness as it can be used to detect end-to-end connection problems over large networks, such as half-open connections.  This feature checks holding register 40002 for a changing heartbeat value provided by a connected device. If the radar does not see a changing value in this register within a definable timeout (1-10sec) then the radar will drop the TCP/socket connection and attempt to re-establish it. This watchdog functionality can be turned on or off via the checkbox.

Heartbeat Fail Timeout (Sec): When this function is enabled, the radar will periodically check the value of Modbus holding register 40002. If the remotely supplied heartbeat value doesn’t change within the specified Heartbeat Fail Timeout period, the radar will drop the TCP socket connection used for Modbus (severing any half-open connections, for example) before restarting the radar's Modbus TCP connection.

Related Information