Compact Mode Input Register Overview

In addition to the Output registers, each RMC module requires two 16-bit registers per axis to hold status information. The first input register for each axis always holds the current axis Status word. The second input register can hold any of several values depending on the value of the command register for the given axis.

When a Sensor DI/O module is installed, the state of inputs 0-17 and outputs 0-7 are reflected in an additional two registers. The contents of these registers is given as follows:

If Compact Mode with Sync is used (versus Compact Mode without Sync), one additional 16-bit register to hold the Synchronization Input is required. See Using the PROFIBUS-DP Compact Mode for details on using this register and the differences between these two sub-modes.

The order of the input registers for an n-axis module with a Sensor DI/O running in Compact Mode with Sync is shown below. I represents the RMC’s input base address. If your module does not have a Sensor DI/O, drop the last two registers:

The following chart shows the same for an RMC running in Compact Mode without Sync:

For most commands, the value returned in the second register for each axis is selected using the Status Area Request bits in the command register. Refer to the individual commands for exceptions. The possible fields that can be returned in the second register when is it controlled by the Status Area Request bits are:

Compact Mode with Sync Example

Suppose you have an RMC100-M1-PROFI and would like the Status and Actual Position for axis 0, and you would like the Status and Drive for axis 1. You would send commands with the following format:

After the Synchronization Output register is incremented, the RMC will process the commands and update the Synchronization Input register to match. At this time, the input registers would hold the following values:

Compact Mode without Sync Example

Suppose you have an RMC100-M1-PROFI and would like the Status and Actual Position for axis 0, and you would like the Status and Drive for axis 1. You would send commands with the following format:

When the RMC sees the changes to the SAR field, it processes the commands. As a result, the input registers would hold the following values:

See also:

Using the PROFIBUS-DP Compact Mode

Compact Mode Output Register Overview

Command Words for PROFIBUS-DP Compact Mode

Copyright (c) 1997-2015 by Delta Computer Systems, Inc.