IFM Electronic AC402S, Programming Manual

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SmartPLC SafeLine AC4S with fieldbus interfaces
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8.6.1 Note on the size of the exchange objects
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The amount of data that can be transmitted with the failsafe network variables is limited. The following
restrictions apply:

mamimum number of connections sender >>> receiver: 10

maximum number of bytes per connection sender >>> receiver: 32

maximum number of bytes in input and output area: 256 each
The required number of bytes for each AC4S is derived from the following equations:

configured sender lists ([Safety network variable list (sender)])

output area (data from failsafe PLC to standard PLC): number of receivers * (user data*2+3)
bytes

input area (data from standard PLC to failsafe PLC): number of receivers * 7 bytes

configured receiver lists ([Safety network variable list (receiver)])

output area (data from failsafe PLC to standard PLC): 7 bytes

input area (data from standard PLC to failsafe PLC): (user data*2+3) bytes
The size of the user data results from the number of created failsafe variables. Depending on the data
type used, failsafe variables require the following storage capacities:
Variable type Size
SAFEBOOL SAFEBOOL variables are bundled in DAFEWORD variables; in each SAFEWORD up to 16
SAFEBOOL variables can be transfer

1...16 variables = 2 bytes

17...32 variables = 4 bytes

33...48 variables = 6 bytes
SAFEINT 1 variable = 2 bytes
SAFEWORD 1 variable = 2 bytes
For broadcast / multicast of varaible lists the above mentioned rules also apply.