DP startup

Before a master device and slave devices can perform cyclic data exchange with each other, parameter and configuration data are transferred from the master device to the slave devices during the DP startup. After sending the parameter data and the configuration data, the master device queries the diagnostic data of the slave device until the slave device signals its readiness for data exchange. Depending on the extent of the calculations, which a slave device has to perform after receiving the parameter data and the configuration data, it can take up to several seconds for a slave device to be ready for data exchange.

Parameter data is sent with a SetPrmLock request telegram from a master device to the slave devices. The SetPrmLock response telegram contains no data and only consists of one byte, which represents a short acknowledgement. Configuration data is sent with the ChkCfg request telegram from a master device to the slave devices. The ChkCfg response telegram contains no data and only consists of one byte, which represents a short acknowledgement. Diagnostic data is requested with a SlaveDiag request telegram from a master device. The SlaveDiag request telegram does not contain any data from the master device. The slave device sends the diagnostic data with a SlaveDiag response telegram.