OPC server and InTouch

[Vidmas30]

Good evening,

I have a question: we are connecting to PC with InTouch SCADA a PLC through Ethernet card (TCP/IP). It is clear with OPC server settings and variables addressing, but question is: when we initializing Ethernet card, we set PLC name, addresses and TCP IP configuration. Do we need to add ScanEX block (as we do with TCP/IP slaves)? Thank you very much!

[Emil]

Hi Vadimas,

No, you don't need! The controller is PCOM (Unitronics native protocol) slave by default. When performing Card Init and PLC name, using defauylt sockets settings, you can communicate from any Unitronics software via port 20256 or 20257.

[Vidmas30]

Hi, Emil,

Thanks for reply. And if we connecting to InTouch directly (without OPC server). Do we need ScanEx block?

[Emil]

Hi Vidmas,

There is no such thing as "direct". There is always some protocol converter, which takes the data from PLC and transfer to GUI of SCADA. In case of OPC server, this is the "translator", then InTouch takes the data as OPC client. If you want to bypass OPC server, you need to use other "translator. As InTouch supports Modbus (Modicon driver) and Unironics supports this protocol too, many customers use this protocol (its serial or IP version - Unitronics supports both) to contact with SCADA.

In case you chose this way (very good choice - already implemented many times), you need ot set thhe controller as Modbus/Modbus IP Slave. Scan EX is one of the elements of this settings, but not thhe only! You need:

COM Init (RS232/485) or Card Init (Ethernet)

Modbus or Modbus IP config;

and then Scan EX.

[Vidmas30]

Thank you, Emil,

We already done this, works perfect!

Could you explain more about SI105(keep alive) and SI109 (connection keep)? If I understand correctly, when there's no traffic in SDW16and SDW20 (socket 2) for a period of time defined, then PLC reinits TCP connection?

[Ofir]

Hi Vidmas,

Please see explanation from help file:

SI103-SI106: (Keep Alive)

Enables the PLC to disconnect if there is no communication from the connected device.

When TCP/IP connection is established (SI 145-148 = 6) check data transport (SDW 14 – 21).

If no data transport occurred during the defined time – perform ‘Socket Init’.

Keep Alive counter is SDW 38

SI107-SI110: (Keep Connection)

Enables the PLC to reconnect when there is no communication from the connected device for the defined time.

Note that the value per socket should be higher than the regular “keep alive” (SI 103 – 106)

Counter of the operation in SDW 45

[Vidmas30]

Hi, Ofir,

I read this on help file, but I just want to make sure. We have a slave PLC (v570) connected through Ethernet card to remot PC. A couple times there was such thing, that PLC was not responding - we could ping IP from PC, but we get no data. From PLC side, the SI147=6, but values SDW16 and SDW20 were not changing. SB's and SI's showed no error. Then we unplugged Ethernet cable and plugged back, and everything's gone fine again.

So the meaning of that question was: can we use it on slave devices to establish connection with master PC?

[Ofir]

Hi Vidmas,

If the PLC is configured to TCP slave then of course it cannot establish connection with the PC. (only TCP master can initiate connection).

Anyway in your case if the PLC is slave then you just need to use the keep alive and not keep connection operands.

If the PLC is configured to master then you need to use Keep connection.

There might be a case where the connection was not closed properly and the PLC socket is still open. This is the reason why the PC cannot connect becasue the socket was not closed properly. Using Keep Alive will make sure to close the socket if there is no data trasport for the predfined time.

[Vidmas30]

Thank you very much, Ofir! Now I got it!