Siemens Industry Online Support
Siemens AG
Entry type: FAQ Entry ID: 13063839, Entry date: 02/15/2008

Why does the online mode not work with the S5-PC converter TTY - RS 232?

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  • Associated product(s)

The converter requires a power supply of +5 V on PIN 14, which is supplied by the controller interface.
This power supply is ensured with the following devices: 

  • AG90U/95U/100U/101U/115U/115H/
  • AG135U/155U  (CPU921, 920, 922, 928A, 928B, 923, 947, 947R, 948)
  • CP530
  • IP252 (only AG115)
  • IP262

The pin assignment for the PC converter (MLFB 6ES5 734-1BD20) is displayed in the following figure:

Fig. 1: interface assignment of the PC converter ( 6 KB )  

Another cause might be that the device is equipped with a low-power interface. These interfaces provide much smaller voltages and currents on the send lines than normal RS232 interfaces. These interfaces are used on the RS232 side in many laptops/desktops and also in some USB adapters. For more information please refer to the manufacturer concerned.

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