Siemens SIMATIC NET SINAUT ST7 System Manual page 186

Installing and putting a TIM into operation
5.4 Options for attachment and settings of the TIM 3 and TIM 4 variants
Determining the receive level
To determine the receive level, the test mode "Test f
modem at the beginning of the trunk line. This modem then sends the upper keying
frequency of the set baud rate constantly on the trunk line. The existing receive level can
then be measured at the end of this trunk line. If the trunk line is a line with one or more
tapping points, all the tapping points in the line must be included in the line (as well as
LTOPs).
Note
When measuring the level, make sure that the 150-ohm (at 9600 / 19,200 bps) or 600-ohm
(at 1200 / 2400 bps) terminating resistor is set at an end point or 6-kohm terminating resistor
at a tapping point. You should also make sure that the line is not grounded during the
measurement since the signal is symmetrical.
The MD2 modem can still received data down to a minimum received level of -43 dB. Which
level is actually present at the reception location can then be checked with an oscilloscope or
level measuring device. If this is not available, the level can also be measured with adequate
accuracy using a normal voltmeter. To help you in this situation, the following table
summarizes the level values and corresponding (approximate) voltage values (U
alternating voltage).
Table 5-23
Level
+10 dB
0 dB
-3 dB
-6 dB
-9 dB
Pinout of the X3 RJ-12 Western jack for the MD2 integrated modem
The X3 connector is designed as a 6-pin RJ-12 Western jack. The pinout is shown in the
following table.
Table 5-24 Pinout of the X3 RJ-12 Western jack for the MD2 integrated modem
Illustration
6
5
4
3
2
1
The RTS signal can be output over the floating optical relay at pins 1 and 6 of the RJ-12
Western connector.
186
Comparison of level and voltage values
Voltage value (AC) Level
2.45 V
775 mV
552 mV
389 mV
274 mV
Pin no. Signal name
5 a1
2 b1
4 a2
3 b2
1 a
RTS
6 b
RTS
H constant
Voltage value (AC) Level
-10 dB 245 mV
-12 dB 195 mV
-15 dB 137 mV
-18 dB 97.8 mV
-20 dB 77.7 mV
Signal direction
Input or bidirectional
(channel 1)
Output or bidirectional
(channel 2)
Output
SINAUT ST7 Station control system - System Manual
System Manual, 05/2007, C79000-G8976-C178-06
" must be set on the MD2
Voltage value (AC)
-25 dB 43.5 mV
-30 dB 24.5 mV
-35 dB 13.7 mV
-40 dB 7.8 mV
-43 dB 5.5 mV
Remark
With 2-wire: Input and output channel 1
With 4-wire: Input
With 2-wire: Input and output channel 2
With 4-wire: Output
Output optical relay
eff