Installation and commissioning of the modems and routers
5.7 Analog dial-up modem MD3
SINAUT ST7 station control system
210
System Manual, 09/2016, C79000-G8976-C178-10
For the connection from the TIM to the first MD3, the 6NH7701-4DL standard connecting
cable is used. For the connection of the other modems, there is no preassembled connecting
cable available. These can, nevertheless, be implemented with standard components from
the SIMATIC S7 range. The same parts can be used as when creating an MPI connection.
As cable, we recommend 6XV1830-0AH10, and as connector 6ES7972-0BA11-0XA0. When
necessary, the RS-485 terminating resistor can be activated on this connector.
Note
Any TIM with an RS-232 interface can be used, in other words, the TIM 3V-IE variants, the
TIM 4R-IE and all TIM 4 types.
Note
Do not forget to activate the terminating resistor for the RS-485 bus on the last connector
using the slider switch.
RS-485 operation of the MD3
If several MD3s are connected in parallel over the RS-485 interface, remember the following
when making the settings for the modem and setting the parameters for the TIM:
1.
The MD3 modem must be set to the profile 15 using the 10-pin DIL switch.
2.
Make sure that this freely configurable profile 15 is occupied with a profile suitable for RS-
485 operation using a PC and a terminal program.
3.
The RS-485 interface must also be activated at the 4-pin DIL switch accessible from
below.
4.
The RS-485 interface of the TIM connected to the MD3 modem must also be activated at
the 8-pin DIL switch accessible from above (applies to all TIM 4 types).
5.
Since data traffic via RS-485 can only be handled in half duplex, the mode of the
connected TIM must be set to half duplex.
6.
After the MD3 has received data and forwarded it to the TIM, the MD3 needs a pause of
several ms, before it is ready to send data. The TIM needs to take this pause into account
by setting an RTS/CTS delay time, in other words after receiving data it may only send
data again after the RTS/CTS delay time has elapsed. The duration of the delay time
depends on the transmission speed used on the dedicated line (see table below).
Table 5- 37 RTS/CTS delay time for MD3 in RS-485 operation
Speed on the dedicated
line
RTS/CTS delay time
Speed on the dedicated
line
RTS/CTS delay time
300 bps
100 ms
14400 bps
10 ms
1200 bps
100 ms
19200 bps
10 ms
2400 bps
50 ms
26400 bps
10 ms
9600 bps
25 ms
33600 bps
10 ms
Содержание SIMATIC NET TeleControl SINAUT ST7
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