viralpatel

nandgate

Dear Experts,

I have one S7200 PLC (CPU 222) and i want to view its data on my PC using Modscan 32 Software. What is the best way to do it?

With Regards,

A V Anand Phani Raj

hi,

yes u can read data from PLC in Modscan using RS232-RS485 converter you cannot use USB-PPI cable.


regards,

viral

From cpu 222 i took output from 3 and 8 and connect to rs 485/232 converter ,then connected to pc(via aten's usb to serial converter) still Modbus Timeout error

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Split from Modscan.

Hello,

you need connect your wires to RS485 pins not 422 in this case. Simply logically, you have defined S7-200 port as RS-485 and therefore you can't put them in RS-422 junction of adapter, also with that shortcuts. Look also to your LED on adapter, in case of all working correctly you can have probably green and amber lights, in case of exchange data. I was working with this kind of adapters long time ago. In case that you'll have connected wires and LED will be amber steady, cross wires on adapter junction, this can be problem with Data A and Data B pins (3/8).

Thanks for reply, as u mention I tried same with 485 (same adapter top 2 pin and turned dip switch 10 off to disable 422 mode).3 & 8 pins are connected to data + and data - respectively. But Same error occur, to get same connection as shown in fig I switch to 422, as it was not possible in 485.

And the led was blinking green, it was earlier red due to fault in supply

Error Modbus Timeout still persist.

Hello,

leave wires connected to RS-485 junction, Data +/-, this is right solution. In case of other problem, you need check your code, also same communication settings on both sides and right address request from Master (in case of your PLC as Master). In other case, proper functionality of adapter can be checked also with simple freeport communication test, but don't know how you're skilled. If not, this can be also checked with 2 serial ports on PC with proper adapters and 2 hyperterminal applications running, send and receive data through adapter. I'll be check for first that adapter functionality, then check Modbus.