Siemens Add 7 AddFEM, Manual

Page: 43 / 148

Mode of Operation AddFEM
3-16
AddFEM
C79000–G8076–C900–03
3.3.3 Self–learning Sign of Life Cycle Time
The self–learning function of the AddFEM expects an alternating sign of life with
code 0x05/0x0A or 0x03/0x0C. The sign–of–life change is sent with the program
cycle time of the fastest application of the AP. The AddFEM calculates the AP cy-
cle time on the basis of the sign–of–life change and defines it as the monitoring
time with a tolerance surplus of 100%. An AP cycle time of 4 ms calculated by the
AddFEM thus results in a monitoring time of 8 ms. The learning time amounts to
approx. 2 s per PROFIBUS DB channel. If the AddFEM does not determine a
sign–of–life change, the self–learning function is not executed and life–of–time mo-
nitoring is not carried out.
3.3.4 Status Information from AddFEM to the AP
The AddFEM returns the received sign of life with the ORed active DP channel
(A/B) and the own “error weighting”, i.e. the error status to the AP. The active DP
channel is returned ORed with the received sign of life in the most significant bit on
byte offset 48.
–
DP channel A active: Byte in the message at byte offset 48 = Sign of life | 0x00
–
DP channel B active: Byte in the message at byte offset 48 = Sign of life | 0x80
The own error weighting (corresponds to the own error status) is transmitted on
byte offset 49 to the AP.
Monitoring and evaluation of the returned sign of life by the AP allows monitoring of
the AddFEM by the AP.
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