Start-Up Behavior Of The Im 157 After Power Is Switched On - Siemens Simatic 6ES7 157-0AD81-0 A0 Series Manual

The IM 157 enters the DP data cycle and is configured by the DP master.
PROFIBUS-PA: IM 157 reads (as far as possible) the PA input data.
No
The IM 157 exits the DP and PA data
cycle.
No
Bit x+43.0 = "1": start-up delay active
Bit x+43.1 = "1": all slaves in data exchange
In S7 operation: x = 100
Figure 8-1

Start-up behavior of the IM 157 after power is switched on

DP/PA Link and Y Link Bus Couplings
A5E00193841-01 1
Power-up of the IM 157
(schematic)
Power on at the IM 157
Bit x+43.0 = 1 in diagnostic frame,
i. e. the start-up delay of the IM 157 is active.
PA output data are set to "0" (CLEAR).
Missing slaves are read in with a "0".
All slaves in the data cycle (bit
x+43.1="1" in the diagnostic frame) or
start-up delay time elapsed?
Yes
Bit x+43.0 is set to 0
Actual = desired
Did the IM 157
involve all slaves in the data cycle during
the power-up delay time?
Yes
PA output data are passed on to the slaves.
Operation of the DP/PA Link and the Y Link
Configuration:
Start-up if ...
Actual desired
IM 157 reads the PA input data.
8-3