Multi-Configuration Mode

Applications of the multi-configuration mode

Multi-configuration mode can be used for the following types of application. A more extensive consideration, considering, in particular, the various implementation levels of the Bus Coupler, is given in the Requirements of a production machine.

Creating a DP configuration for various implementation levels of the Bus Coupler

If a PLC program is to be used for controlling different configurations of a process, it may make sense to use the same DP configuration even if the terminal configuration is different. In this case the address offsets in the process image do not change, and the DP configuration of the PROFIBUS DP master does not have to be re-saved for each version. With the multi-configuration mode it is now possible to define a maximum configuration for the Bus Coupler, and in this case it will only be necessary to disable those terminals that are not present in accordance with the current implementation level.

Reserved Bus Terminals

Because all the analog terminals are configured first in the DP configuration, before the digital terminals, the consequence of inserting analog terminals at a later stage is that the address offsets of the digital terminals are shifted. The insertion of a digital terminal within the existing terminal structure (which can, for instance, be useful if digital terminals with different input voltages are used) also has the consequence that the offsets of the digital terminals that follow it are shifted. If a digital terminal is inserted before the end terminal however, the offset of the existing terminals are not shifted. With multi-configuration mode it is now possible to configure additional terminals as reserves at any location within the terminal structure.

Assigning the Bus Terminals to freely chosen process image addresses

Because digital terminals are always grouped into bytes, which therefore means that the smallest DP configuration module is an 8-bit module, a difficulty arises when the associated terminals are to be distributed over a number of bytes in the PLC process image. This is because in the PLC it is usually only possible to assign addresses for each DP configuration module. With multi-configuration mode it is now possible to configure additional digital terminals as "dummy" terminals at any desired locations, enabling the address offsets of the other terminals to be shifted in the PLC process image.

Setting the multi-configuration mode

Multi-configuration mode is activated via the UserPrmData:

Rules for multi-configuration mode

Multi-configuration mode requires a few additional rules to be observed, in addition to those for standard configuration:

• Only one DP module may be configured for each analog terminal
• The digital terminals are to be declared as KLxxxx Multi-Cfg mode modules at their true position
• The digital terminals are to be declared after the analog modules moreover as input/output sum modules, corresponding to their bit width, as is also the case for standard configuration in the process image.
• All modules for the maximum configuration, including the reserve modules, are to be declared
• Modules that are not inserted must be disabled

Enabling/disabling Bus Terminals

Those Bus Terminals that are present in the DP configuration, but that are not in fact plugged in, must be disabled. This can be done in the UserPrmData, via DPV1, KS2000 or through the 2-byte PLC interface.

Making the setting through DPV1 or through the 2-byte PLC interface has the advantage that the terminal assignment for the multi-configuration mode can usually be made directly from the PLC program, without having to change the DP configuration of the master.

As long as the inserted Bus Terminals do not agree with the non-disabled Bus Terminals to be expected from the DP configuration, the Bus Terminal will normally set the Stat_Diag bit in the diagnostic data, with the consequence that it is not yet ready for cyclic data exchange.

If, however, the enabling and disabling is to be carried out via the 2-byte PLC interface, it is a precondition for function of the 2-byte PLC interface that the coupler is in cyclic data exchange mode. For that reason it is also possible to deactivate remaining in the Stat_Diag state:

Enabling/disabling via UserPrmData

The assignment of the terminals (a maximum of 128 terminals is possible) is entered from byte 15 to byte 30 and from byte 41 to byte 56 of the UserPrmData. Two bits are reserved here for each terminal, indicating whether the relevant terminal is enabled (value 0) or disabled (value 2). If the UserPrmData is to be displayed as text in the DP configuration tool, then the parameters Assignment of module x are to be set to DP DataExchange (enabled) or Multi-Config. mode (disabled).

Enabling/disabling via DPV1 Write

The terminals are enabled/disabled through Slot_Number 0 and Index 1 or 2:

Enabling/disabling via the 2-byte PLC interface or through KS2000

The terminals are enabled or disabled through table 1, registers 0-31:

Note the size of the Cfg data It can happen under multi-configuration mode that the CfgData exceeds 64 bytes. In such a case, the CfgData must be enlarged.