Plc Program "Control Unit Switchover - Siemens SINUMERIK 840D sl Function Manual

B3: Several operator panels connected to several NCUs, distributed systems - only 840D sl
Activating/deactivating the MCP
If an MCP is assigned to the PCU in the NETNAMES.INI file, it is activated/deactivated as
part of the operating mode change. The MCP switchover in the PLC is called by the
operating mode change as a subfunction.
PCU changes operating mode
Active -> passive
Passive -> Active
2.2.14

PLC program "Control Unit Switchover"

Introduction
Control unit switchover is an important controlling function in the overall M:N concept:
● The PLC control unit switchover checks the priorities of the requests and the states of the
● The NCU sets signals and evaluates signals required in connection with the control unit
The control unit switchover function is a software package in the toolbox. It is immediately
available with its standard functionality, but can be modified for special applications
according to individual requirements.
Provision is made for two categories of modification:
1. Simple parameterization of standard functionality
2. More fundamental reconfiguring of the control unit switchover function
Reasons for more fundamental (user-specific) reconfiguring can be as follows:
● Suppression strategy which differs from standard functionality
● Operating mode switchover which differs from standard functionality
● Independent handling of override switch for switchover of control unit
● Existence of a 2nd machine control panel on a PCU.
Program structure
The control unit switchover program consists of:
1. FB101/DB101: Online/offline operating mode switchover
2. FB102/DB102: Active/passive operating mode switchover
3. FC103: Machine control panel switchover
Every program section is implemented in a separate function block (FB) or function (FC).
The variables are stored in a separate instance data block (DB) for each FB. The control unit
switchover main program is stored in FB101. FB101 must be called in an organization block
(OB) in order to activate the functions. FB102 and FC103 are called repeatedly in FB101.
Extended Functions
Function Manual, 09/2009, 6FC5397-1BP20-0BA0
2.2 Several operator panel fronts and NCUs with control unit management option
components involved and switches over if necessary.
switchover function.
MCP is
Deactivated
Activated
125