Applies To:
  • CitectSCADA 5.xx

The S7-200 PLC is a small powerful PLC that has a small number of I/O. How do I get Citect to communicate with it? 

The methods of connecting Citect and an Siemens S7-200 PLC include:
  1. The S7-200 series with a 214 processor (or better) can be programmed to use the serial port of the PLC with the MODBUS protocol. This method takes up quite a bit of PLC memory and hence only the 214 processors (or better) are capable of handling this. Presumably some scan time is used up also. The PLC source code can be provided by Citect Support on request, or can be found on the FTP site as S7MODBUS.ZIP. This method uses Citect's standard MODBUS driver.
  2. Citect has a I/O device driver using a product called APPLICOM by APPLICOM International that allows communications using the S7's native PPI protocol. The purchase of the APPLICOM product (which includes a communications card) is required, but no PLC code is required. Go to this link to get details of the Applicom product
  3. A driver developed by a Citect distributor is available. This driver is not currently supported by Ci Technologies, although it can be obtained from Citect Support on request. This driver does not require any additional hardware or software to operate. It is planned that this driver will be included in the Citect product at some future point.