Defining The Basic Parameter Arguments For S5-95U Plcs - Siemens SIMATIC S5 Manual

System Description
Rules for Setting the Basic Parameters
• TLN 0 (default) is not allowed for the S5-95U as L2 station (TLN 0 is reserved for a pro-
grammer). You must change the value for TLN 0, otherwise the programmable controller stays
in the STOP mode.
• Do not delete any relevant parameters, otherwise the PLC will stay in the STOP mode! Delete
any irrelevant parameters (in the case of passive S5-95Us).
• The following basic parameters must be the same for all stations in the SINEC L2 network:
BDR, HSA, TRT, SET, ST, SDT 1 and SDT 2. Always take the basic parameters of the slowest
station! The slowest station is the station with the longest slot time in the SINEC L2 network.
Example: Communications between the CP 5410, S5-95U and CP 5430-0: preset baud rate
187.5 kbaud. The CP 5430-0 with 400 bit time units has the longest slot time
(default value). Set the basic parameters of the CP 5430-0 (187.5 kbaud) for all
stations (see Table 1-5).
Communications with S5-95Us (homogeneous S5-95U networks)
Define the arguments of the BDR, SET, ST, SDT 1 and SDT 2 basic parameters for the S5-95U
programmable controllers in DB1 (see Table 1-3).
Table 1-3. Defining the Basic Parameter Arguments for S5-95U PLCs
Baudrate
Basic in kbaud
parameters
in bit time units
SET
ST
SDT 1
SDT 2
Example: Define the baud rate as 187.5 kbaud in DB1. This gives the other basic parameters
as follows:
Bit time unit
You must specify certain parameters, e.g. the target rotation time, in bit time units. To calculate the
times in milliseconds from the bit time units, use the following formula:
Time (in milliseconds) =
1-10
9.6 19.2
0 0
73 76
12 12
40 60
SET 0 ST 170 SDT 1 12
Number of bit time units
Baud rate (in kbits/s)
93.75 187.5
0 0
99 170
12 12
80 150
SDT 2 150.
1 bit time unit
e.g., time=
9.6 kbits/s
S5-95U, SINEC L2
500 1500
0 60
400 1000
12 150
360 980
= 0.104 ms
EWA 4NEB 812 6112-02