Service commands
EtherCAT® datagrams transport various service commands and are addressed to one or several slaves in the network.
The master sends, receives, and evaluates service commands. Each service command has a working counter (WC). The purpose of the working counter is to provide feedback to the master whether data has been exchanged successfully or not. This feedback is obtained in the same cycle.
The following service commands are defined:
Service command
| Description | |
|---|---|---|
APRD | Auto Increment Read | Slave increment address. The slave writes read data into the EtherCAT® datagram if the received address is zero. |
APWR | Auto Increment Write | Slave increment address. The slave writes data into memory location if the received address is zero. |
APRW | Auto Increment Read Write | Slave increment address. The slave writes read data into the EtherCAT® datagram and writes the data to the same memory location if the received address is zero. |
FPRD | Configured Address Read | The slave writes read data into the EtherCAT® diagram if the received address is identical with one of the configured addresses. |
FPWR | Configured Address Write | The slave writes data into the memory location if the address is identical with one of its configured addresses. |
FPRW | Configured Address Read Write | The slave writes read data into the EtherCAT® datagram and writes the data into the same memory location if the received address is identical with one of the configured addresses. |
BRD | Broadcast Read | All slaves write the logical OR of the data of the memory location and of the EtherCAT® datagram into the EtherCAT® datagram. All slaves increment the position field. |
BWR | Broadcast Write | All slaves write data to the memory location. All slaves increment the position field. |
BRW | Broadcast Read Write | All slaves put logical OR of data of the memory area and data of the EtherCAT® datagram into the EtherCAT® datagram and write data into memory location. BRW is typically not used. All slaves increment to the position field. |
LRD | Logical Memory Read | The slave writes read data into the EtherCAT® datagram if the received address is identical with one of the configured FMMU areas for reading. |
LWR | Logical Memory Write | The slave writes data into the memory location if the received address is identical with one of the configured FMMU areas for writing. |
LRW | Logical Memory Read Write | The slave writes read data into the EtherCAT® datagram if the received address is identical with one of the configured FMMU areas for reading. The slave writes data into the memory location if the received address is identical with one of the configured FMMU areas for writing. |
APMW | Auto Increment Read Multiple Write | The slave increments the address. The slave writes read data into the EtherCAT® datagram if the received address is zero. Else the slave writes the data into the memory location. |
FRMW | Configured Read Multiple Write | The slave writes read data into the EtherCAT® diagram if the address is identical with one of the configured addresses. Else the slave writes the data into the memory location. |
INFORMATION
