Milltronics CVCC Manuál s instrukcemi stáhnout pdf (Strana 62)

PLC REQUIREMENTS

As Programmable Logic Controllers continue to revolutionize the process control industry, new and

innovative ideas become reality very quickly. The BIC-II was designed to be compatible with PLC’s of the

future, as well as those which have already been commisioned a number of years ago.

To this end, the BIC-II provides communication protocol options which should suit all application

requirements.

One important consideration is that the BIC-II is strictly a slave device. As many PLC’s are also slave

devices, some means must be provided to initiate communications.

PLC ASCII Basic Modules

Many PLC manufacturers provide an optional ASCII basic module. For older PLC’s, or PLC’s utilizing

Modbus protocol, this may be the only option available to establish the PLC as the Master to the Slave BIC-II.

In this case, custom Master driver software must be developed for the PLC. The software developer may

choose to use any of the BIC-II protocols.

Modbus Plus PLC’s

Some PLC’s are Modbus Plus compatible. When a Modbus Plus PLC is used in conjuction with a Modbus

Plus to Modbus bridge, a custom driver is not required. A simple start up procedure is included at the end of

this section for the Modicon BM-85 Bridge Multiplexer. Refer to Appendices/Modicon BM-85 Quick Start.

Allen Bradley PLC’s

Allen Bradley has established a proprietary protocol, "Data Highway Plus". When using this PLC a Data

Highway Plus to Modbus bridge must be installed between the PLC and BIC-II.

Future PLC’s

As the popularity of Modbus protocol continues to increase, many PLC manufacturers are quickly developing

Master PLC’s with interface modules, or Slave PLC’s with special Master ASCII drivers to suit Modbus ASCII

Slave devices, such as the BIC-II.

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Milltronics CVCC Manuál s instrukcemi Strana 62