Representation
DFB representation:
For an extended description of this DFB, refer to the EcoStruxure™ Control Expert, Safety, Block Library.
Description
The DFB S_WR_ETH_MX2 is for PAC using CPU firmware 3.20 or later. It calculates data (reserved data containing a CRC and a time stamp) required by the receiver to check and manage errors detected during the safe peer-to-peer communication.
The S_WR_ETH_MX2 DFB function
block has to be called at each cycle in the sender PAC. Within the
cycle, it has to be executed in the logic after all required modifications
have been performed on the data to be sent. This means that the data
to be sent may not be modified within the cycle after the execution
of the DFB, otherwise the CRC information used in the reserved data
area will not be correct and the safe peer-to-peer communication will
not succeed.
You have to assign the ID parameter
a unique value that identifies the safe peer-to-peer communication
between a sender and a receiver.
| WARNING | |
|---|---|
LOSS OF ABILITY TO PERFORM SAFETY FUNCTIONS The ID parameter value must be unique
and fixed in the network for a sender/receiver pair.Failure to follow these instructions can result in death, serious injury, or equipment damage. | |
DATA_SAFE Array
Description
Use the tabs in both the and the in Control Expert to make the link between the process variables and the safety variables.
Linking process and safety variables in this manner makes it possible to:
Transfer the value of safety variables to process variables, via linked global variables.
Send variable values from the process area of the sending PAC to the process area of the receiving PAC, via explicit messaging over Modbus TCP.
DATA_SAFE array is composed of two zones:
The User Safety Data zone contains the data from the safe area of the PAC. This zone starts at index 0 and finishes at index 90.
The Reserved Data zone is reserved for auto-generated diagnostic data, including a CRC and time-stamp. This data is used by the receiving PAC to determine if the data contained in the User Safety Data zone is safe or not. This zone starts at index 91 and finishes at index 99.
NOTE: Do not write in the Reserved Data zone.
DATA_SAFE array (array[0..99] of INT) structure
representation:
