This driver is a simple driver. It provides additional functionality to enable ClearSCADA to interface with specific supported devices using a particular protocol. To interact successfully with such devices, you need to:
- Install and run the driver
- Ensure that the driver is licensed
- Configure the required database items and settings on the driver
- Ensure that the database items (and any database items on which they depend) have valid, saved, configuration and are 'In Service'.
The Modbus Slave Driver allows a ClearSCADA system to act as a Modbus PLC and report any data changes back to its Master. The Slave transmits any changes to its database, or sets values or states in its database, upon request from its Master.
The Slave can obtain its data directly from plant, from calculated values, or from any item in the ClearSCADA database. Its Master can be another ClearSCADA server, or a third party server that is using the Modbus protocol.
The Modbus Slave Driver provides extra functionality within a ClearSCADA server for transmitting data or controlling points. A Modbus Slave uses Value Maps for mapping point properties into memory, so that they can be accessed by the Modbus protocol.
The Modbus Slave documentation explains how to configure Modbus Slave-specific features and items within the ClearSCADA database—see, as applicable:
- Configuring Modbus Slave Devices in ClearSCADA
- Using Value Maps to Represent Modbus Data Address Ranges
- Modbus Function Codes Supported by the ClearSCADA Modbus Slave Driver
- Typical Scenarios.
It also explains driver-specific aspects that are of interest to system administrators and engineers when investigating unexpected system behavior (relating to the Modbus Slave driver):
NOTE: There are no driver-specific pick actions for database items on this particular driver. However, users with the required privileges can add custom pick actions to a database item by using the User Methods tab on the relevant configuration Form (see Using the User Methods Tab to Define Custom Actions in the ClearSCADA Guide to Core Configuration). See a system administrator for the documentation associated with such custom actions (also known as ‘methods’).