PROFIBUS-DP Slave Communications Overview

PROFIBUS-DP Slave is the communication protocol available on the RMC75P and on the RMC150E PROFIBUS module. PROFIBUS-DP is an open industrial fieldbus and is vendor independent, allowing a large range of PLCs and other PROFIBUS masters to control the RMC. The RMC performs as a PROFIBUS-DP slave, requiring a PROFIBUS-DP master to control it. The type of the actual master—whether a PLC or other controller—is unimportant.

RMC PROFIBUS-DP Specifications

	RMC75P	RMC150E PROFIBUS
Baud Rates	9.6Kbaud to 12Mbaud
Product Identifier Number	0x07E1	0x0AC6
Supported	Freeze mode, sync mode, automatic baud-rate detect
Modularity	The RMC is a modular station that can have one module selected at a time.
Station Addresses	0-99 (selected by rotary switches)	1-126 (set in RMCTools or by Set_Slave_Address function from a PROFIBUS Class 2 Master)

PROFIBUS-DP Modes

RMC150E and RMC75P

The following modes are available on the RMC150E and RMC75P:

Each of these modes specifies a number of 32-bit registers, n. For each mode, n registers are continuously sent from the RMC's first n Indirect Data Map registers to the PLC, and n registers are always sent from the PLC to the first n registers in the RMC's Variable Table.

Choose the mode with the number of registers you need for your application. For details on how to use these modes, see the PROFIBUS Mode: I/O Modes topic.

RMC75P Only

In addition to the I/O modes described above, the RMC75P supports Basic/Enhanced PROFIBUS Modes. These modes are generally more difficult to use. Therefore, most users will prefer the cyclic modes. For details on these additional modes, see the Basic/Enhanced PROFIBUS Modes topic.

PROFIBUS Configuration

For details on configuring the PROFIBUS, see the PROFIBUS Configuration topic.

Connection Status

The PROFIBUS Connection Status register provides information on the PROFIBUS connection. This register is located at:

RMC75P: %MD21.6

RMC150: %MD45.6

This register has one bit defined, which can be used within the RMC user programs as part of handling broken connections:

Bit	Description
0	Connection Established. This bit will be set when the PROFIBUS interface is in the Data Exchange mode.

Troubleshooting

For details on how to troubleshoot the RMC PROFIBUS, see the Troubleshooting PROFIBUS topic.