Product Information PCS7/TM V2.02 24.10.2001
Siemens AG 2001 17 of 21
8 Bus Parameters for PROFIBUS TM System Bus on ASx88/TMand WinCC
Parameter
description DOS_CONF.DAT
in AS488 and

Bridge

L2AMPRO.INI

in

ASx88
Configura-

tion dialog in

Windows NT

for WinCC

Value
Highest station address
l2_hsa
l2_hsa
Highest Sta-
tion Address
1 .... 126
Local device address
l2_ts
l2_ts
Local Station
Address
1 .... 99
Baud rates (index)
l2_baud_rate
l2_baud_rate
Transmission
Rate 1,5 Mbits/s
Slot time
l2_tsl
l2_tsl
Tslot
3000
Quiet time
l2_tqui
l2_tqui
Tqui
0
Setup time
l2_tset
l2_tset
Tset
240
Minimum station delay
time
l2_max_tsdr
l2_max_tsdr
Max Tsdr
980
Maximum station delay

time

l2_min_tsdr
l2_min_tsdr
Min Tsdr
150
Token rotation time
l2_ttr
l2_ttr
Ttr
min.
90000 *)
GAP factor
l2_g
l2_g
Gap factor
30 **)
Call repetitions
l2_retry_ctr
-
Retry Limit
1
Ready time
-
-
Trdy
150
Idle time 1
-
-
Tid1
515
Idle time 2
-
-
Tid2
980
• The PROFIBUS bus parameters for WinCC are specified in the user-defined profile. But for the Ttr parame-
ter, the values of the general-purpose profile will be transferred to the user-defined profile if the general-
purpose profile is selected beforehand. In this case, these values are almost identical to the above-
mentioned ones.
• *) Use the following formula to calculate the Ttr parameter, and enter it:
Ttr (l2_ttr) = 9000 * [number of active PROFIBUS-TM devices].
Note: The factor 9000 in the formula is only valid for a baud rate of 1.5 Mbits/s.
• **) For the baud rate of 1.5 Mbits/s, the default value of the gap factor is 30 – 50. Entering a smaller value
may be necessary in exceptional cases.
• All specified bus parameters are tuned to the baud rate of 1.5 Mbits/s. Any change/optimization requires a
deep knowledge of the PROFIBUS standard.
• The bus parameters for all TELEPERM components (e.g. OS525 and PROGRAF AS) on the PROFIBUS TM
system bus must be selected accordingly.