On / off-Handshake with PLC
During block search PLC is informed about each technological M-function as in normal execution but has to simulate the execution of this request respectively. Therefore, PLC is informed about each change of block search mode (off / on) and must acknowledge this change to NC. The NC waits for the acknowledgement of PLC as for synchronized M-functions.
If block search is active during CNC-reset, block search is turned off without handshake with PLC (PLC may be informed about reset specific Control Unit).
Block search on / off | |
Description | During each turn off/on request of block search the NC does a handshake with the PLC, informing the PLC and waiting for acknowledgement from PLC. For this purpose, the PLC must indicate, by setting element X_Enable, that it would like to be informed about block search changes. |
| LCControlBoolUnit, see Description Control Unit |
Access | NCK sets this value to TRUE for asking the PLC for block search on. The PLC acknowledges by setting X_State to TRUE (and vice a versa). |
ST path | pMC[channel_idx]^.addr^.LCControlBahn_Data.LCControlBoolUnit_BlockSearch |
Commanded Value | |
ST element | LCControlBoolUnit_BlockSearch.X_Command |
Information flow | NCK → PLC |
Data type | BOOLEAN |
Value range | [TRUE = block search on reset request from NCK to PLC, |
Return value | |
ST element | LCControlBoolUnit_BlockSearch.X_State |
Information flow | PLC → NCK |
Data type | BOOLEAN |
Value range | [TRUE = PLC has acknowledged block search on, FALSE = block search off] |
Request | |
ST element | LCControlBoolUnit_BlockSearch.X_Enable |
