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S5-95F
Coordinating Frame Sequences (95F Mode)
The S5-95F does not send a "new" useful message frame until the receiver's operating system has
retrieved the data in the "old" useful message frame. The transmitter, however, does not receive an
acknowledgement which tells it whether the receiver's user program has actually evaluated the
useful message frame.
Because the S5-95F clears the Receive mailbox when a power failure occurs, frame loss ensues the
receiver's operating system received the frame but the user program did not evaluate it before the
power failed. If your automated process cannot tolerate frame loss, you must monitor the frame
sequence at the user level via an acknowledgement system. This requires a data path from the
receiver to the transmitter.
Safety Note
SINEC L1 nodes receive no acknowledgement to inform them whether the receiver has
actually evaluated the frame that was sent. If your automated process requires failsafe
frame coordination, you must monitor the frame sequence with an acknowledgement
system.
Coordinating Frame Sequences (115F-14 and 115F-15 Modes)
The S5-95F resets bit 0 or 2 of the UVB after sending the frame, even if the receiver's operating
system has not accepted the data of the old frame.
Safety Note
When you use message modes 115F-14 and 115F-15, the S5-95F useful frame
monitoring feature is deactivated. To prevent an undetected frame loss, you must not
alter the send mailbox more than once during each safety time for Receive. If your
automated process requires failsafe frame coordination, you must monitor the frame
sequence with an acknowledgement system.
Restrictions When Using the S5-95F with Basic Units 095-8FA01
You specify the system response to SINEC L1 errors when assigning the parameters with COM 95F.
Warning
!
The parameter entry "Slave type S5-115F" with "Response to SINEC L1 error in
user program" is not permitted for S5-95F PLCs with basic units 095-8FA01. This
parameter assignment could result in a nonfailsafe response from the S5-95F.
EWA 4NEB 812 6210-02
Rules for Failsafe Operation of an S5-95F
18-37
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