SoftPLC Now Speaks Modbus Slave Too! |

SoftPLC Now Speaks Modbus Slave Too!

September, 2002: SoftPLC now also provides a Modbus RTU Slave protocol driver, in addition to the rich communications protocol set already supported by this open architecture controller (which includes TCP/IP ethernet, Data Highway, A-B DF1 serial, Modbus Master, and more). The driver is now included with all SoftPLC systems at no cost.

This new Modbus Slave driver makes it easy for SoftPLC users to interface to even more products such as Distributed Control Systems (DCS) and SCADA systems. Up to 8 serial ports are supported for slave connections to multiple Modbus Master systems/devices. Over 1 million tags can be defined in a single SoftPLC controller.

Example applications for SoftPLC utilizing the Modbus Slave driver include:

Process or machine control applications where the PLC (SoftPLC) needs to interface to a DCS or SCADA system over Modbus.

Replace an obsolete proprietary controller (such as an Allen-Bradley PLC-3 or PLC-5) with SoftPLC, leaving the original DCS and/or SCADA system programming intact. Automatic ladder logic control code conversion is available for Allen-Bradley PLC models and customers can elect to use the existing I/O and/or replace it with another brand, including SoftPLC In Tealware.

SoftPLC can be used as a data concentrator to multiple HMI/SCADA systems using the 8 serial ports concurrently. The concentrated data can then be transferred over ethernet via an in-plant intranet or the internet to another system for analysis, reporting, etc. using SoftPLC s ability to interact with standard databases, or by having SoftPLC send an email message with the data embedded or attached.

A simple single port protocol solution for simple HMI's that may not support other SoftPLC protocols.

SoftPLC can act as a gateway between a Modicon PLC or other Modbus Master devices to an Allen-Bradley network, such as Data Highway Plus or A-B Ethernet.

Features of the Modbus Slave Driver include:

Supports most commonly used Modbus Functions (0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x08, 0x0F, 0x10, 0x16)

Supports up to 8 ports loading only a single driver instance.

Each port can have its own mapping of: (a) holding registers; (b) input registers; (c) input states; (d) output coils. A configuration file is dedicated to each of these 4 Modicon data areas for each port.

Each port can be assigned its own baudrate, parity, databits, and stopbits.

Special global options include DEBUG and IOCHECK. DEBUG allows for additional diagnostic output. IOCHECK allows the user to reduce the turn around time by having SoftPLC service the Modbus commands more frequently.

Easy configuration is done via TOPDOC NexGen using a simple text file.
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