PLC interface
Control units
The PLC can command options of forward/backward on path via three BOOLEAN control units:
Backwards | |
Description | Command to move backwards on path. |
Datatype | MC_CONTROL_BOOL_UNIT, see description Control Unit |
Characteristics |
|
Access | PLC reads request_r + state_r ahnd writes command_w + enable_w |
ST-Path | gpCh[channel_idx]^.bahn_mc_control.backward_motion pMC[channel_idx]^.addr^.MCControlBahn_Data.MCControlBoolUnit_BackwardMotion |
Commanded, requested, and return value | |
ST-Element | .command_w .request_r .state_r |
Datatype | BOOL |
Value range | [TRUE, FALSE] |
Redirection | |
ST-Element | .enable_w |
Simulated forward movement | |
Description | Command to move forwards in simulation. E.g. in this mode M-function synchronization are handled different. |
Datatype | MC_CONTROL_BOOL_UNIT, see description Control Unit |
Characteristics |
|
Access | PLC reads request_r + state_r and writes command_w + enable_w |
ST-Path | gpCh[channel_idx]^.bahn_mc_control.simulate_motion pMC[channel_idx]^.addr^.MCControlBahn_Data.MCControlBoolUnit_SimulateMotion |
Commanded, requested and return value | |
ST-Element | .command_w .request_r .state_r |
Datatype | BOOL |
Value range | [TRUE, FALSE] |
Redirection | |
ST-Element | .enable_w |
Reset backward storage | |
Description | Turns the backward storage off. No further block is saved in the backward storage. |
Datatype | MC_CONTROL_BOOL_UNIT, see description Control Unit |
Characteristics |
|
Access | PLC reads request_r + state_r and writes command_w + enable_w |
ST-Path | gpCh[channel_idx]^.bahn_mc_control.backward_storage_off pMC[channel_idx]^.addr^.MCControlBahn_Data.MCControlBoolUnit_ResetBackwardStorage |
Commanded, requested and return value | |
ST-Element | .command_w .request_r .state_r |
Datatyp | BOOL |
Value range | [TRUE, FALSE] |
Redirection | |
ST-Element | .enable_w |
M-Functions while Forward/ backward on path
By default, the synchronization of the M-functions in mode backward on path and forward on path are suppressed. If necessary, the synchronization can be enabled by specific bits.
Use of backward storage
Using these bits, in backward direction all synchronized M-functions are handled as MVS_SVS (commanded before block and synchronized before block), in forward direction the synchronization is the original mode as given in channel parameter list.
To turn the saving of function blocks in the backward storage on or off is just allowed if no program is in execution and not backward motion is active. When turning the storage off and on again after program end, the storage is cleared. By this it is ensured, that any following backward movement cannot move further back than to this point.
NC-Reset
Additionally, the backward storage is cleared in each NC-reset.