Siemens SIMATIC NET SINAUT ST7 System Manual page 260

Installing and putting a SINAUT modem into operation
6.4 MD2 dedicated line modem
Core diameter 0.9 mm
9600 / 19,200
Core diameter 1.2 mm
9600 / 19,200
Core diameter 1.4 mm
9600 / 19,200
NTP = number of tapping points
*) not permitted with postal leased lines. Transmit level must be set to –9 dB.
The values in the table are guidelines.
When calculating the maximum range, a power margin of 4 dB was included. This is to
compensate for fluctuations in cable properties that experience has shown to occur in
practise, and thus always ensure that sufficient signal level is available for problem-free data
transmission. To calculate the values shown in the table, the following formula was used:
S
m ax
A
Insert
A
Cable
A
LTOP
NTP
N
min
N
Send
N
Res
S
max
Sample calculation:
For core diameter 0.8 mm, at 2400 bps, with LTOPs and transmit level –6 dB
260
1200 36.2 – NTP x 0.9
2400 29.6 – NTP x 0.6
11.9 – NTP x 0.9
1200 50.1 – NTP x 1.3
2400 43.4 – NTP x 0.8
17.2 – NTP x 1.3
1200 59.2 – NTP x 1.5
2400 54.3 – NTP x 1
20.6 – NTP x 1.5
[ ]
+ − −
N N N
m in
=
Send Res
A
Cable
Insertion loss per tapping point [in dB]
Attenuation per km of the cable used [in dB]
Attenuation per LTOP [in dB]
Number of tapping points
Minimum receive level [in dB]
(-43 dB for MD2, please use only absolute value in formula)
Transmit level [in dB]
(normally –6 dB or 0 dB)
Power margin [in dB]
Max. range [in km]
Maximum range (km)
36.6 – NTP x 0.5
30 – NTP x 0.2
12.6 – NTP x 0.1
50.7 – NTP x 0.7
44 – NTP x 0.3
18.3 – NTP x 0.2
60 – NTP x 0.8
55 – NTP x 0.4
22 – NTP x 0.2
+
2 ×
A
A
− × Insert
LTOP
NTP
A
SINAUT ST7 Station control system - System Manual
42.8 – NTP x 0.9
35 – NTP x 0.6
14.2 – NTP x 0.9
59.3 – NTP x 1.3
51.4 – NTP x 0.8
20.5 – NTP x 1.3
70.1 – NTP x 1.5
64.3 – NTP x 1
24.6 – NTP x 1.5
2 ×
A
LTOP
Cable
System Manual, 05/2007, C79000-G8976-C178-06
43.3 – NTP x 0.5
35.4 – NTP x 0.2
15 – NTP x 0.1
60 – NTP x 0.7
52 – NTP x 0.3
21.6 – NTP x 0.2
70.9 – NTP x 0.8
65 – NTP x 0.4
26 – NTP x 0.2