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Parameters of DB1
C.5
DP Parameters – Block ID "DPS"
Meaning
Data Transfer
Table C-8
DPS Parameters
Parameter
Values
NWI
0 ... 16
NWO
0 ... 16
DPWD
50 ... 65535
Consistent Data
C-10
You specify the parameters for the DP connection with block identifier DPS.
An explanation of the individual parameters can be found in Table C-8.
With block identifier DPS, you inform the CP 541 that it is to store data for
node address 0 in the DP transfer area. Data transmission is not safety-re-
lated.
Observe the syntax of DB1 (see Appendix C.2).
The DP master fetches the data in the DP transfer area and simultaneously
stores the input data for the CP 541. The CP 541 sends the new data with
node source address 0 to the connected programmable controller.
Number word input (length of receive data)
With parameter NWI, you specify the volume in words of the receive data
from the DP master (sent by the DP master).
You enter the values for input and output data separately.
Number word output (length of send data)
With parameter NWO you specify the volume in words of the send data to
the DP master (made available for the DP master).
You enter the values for the input and output data separately.
DP watchdog (DP response monitoring time)
The DP watchdog serves to monitor the DP connection between the CP 541
and the connected programmable controller.
The DP watchdog specifies the time within which a new DP message must be
sent from the connected programmable controller to the CP 541.
If the CP 541 does not receive a new DP message with node address 0 within
the DP watchdog, an error message in the form of a diagnosis will be issued
to the DP master.
Specify the DP watchdog so that the connected programmable controller can
reliably send a DP message within this time. Take into account all interrupt
processing times within your user program.
DP monitoring becomes active as soon as the CP 541 is accepted in the DP
cycle and DP monitoring has been activated by the DP master.
Enter the DP monitoring time in multiples of 10 ms.
DPWD has the internal default 50 (= 500 ms), even with no specification in
DB1.
The input and output data to the DP master and from it are word-consistent.
Meaning
Communications Processor CP 541
EWA 4NEB 812 6188-02
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