Milltronics CVCC Instrukcja Obsługi Pobierz pdf (Strona 43)

MODBUS PROTOCOL

GENERAL

In recent years, Modbus has become an industry standard communications protocol for

PLC’s

(Programmable Logic Controllers) and

DCS’s

(Distributed Control Systems).

The BIC-II supports Modbus ASCII (non RTU) communications. Modbus ASCII is the transmission mode

utilized by a variety of off-the-shelf operator interface (MMI) software packages including:

» InTouch

(by WonderWare)

» Paragon

(by InTech Control Systems)

» Factory Link

(by US Data)

» Mod Cell

(by Modicon)

This section assumes the user is completely familiarized with the software package, and communications

system components selected. The following information is specific to the BIC-II, when installed in such a

system.

If the BIC-II is connected to an IBM PC compatible computer based communications system, the BIC-II is

slave to the computer master. Proceed to BIC-II Registers.

If the BIC-II is connected to a PLC (also a slave device) refer to Appendices/PLC Requirements, before

proceeding.

BIC-II REGISTERS

The BIC-II memory is divided into PLC type holding registers. These registers are used to store information

about the BIC-II, the Milltronics product connected to the BIC-II, and the process being monitored by the

Milltronics product. Each register can store 16 bits (4 ASCII characters of information).

All BIC-II holding registers are within the range of 40001 to 49999. Up to 59 registers may be read per

request. Registers must be written to individually.

ModBus ASCII register specifications refer to the last four digits of the register number,

referenced to zero and expressed as a hexadecimal number.

e.g. register 46001 = 6000 ($177Ø)

Refer to APPENDICES\BIC-II Modbus Register Map for a complete list of holding registers.

Some registers are used, regardless of the Milltronics product(s) connected to the BIC-II. These are referred

to as BIC-II General Registers. Other register usage varies dependent upon the Milltronics product(s)

connected to the BIC-II. These registers are referred to as BIC-II Product Data Registers.

* indicates a registered trademark of the company specified.

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Milltronics CVCC Instrukcja Obsługi Strona 43