Applies To:
  • CitectSCADA x.x
Summary:
Question: We have a Citect system communicating with a Koyo/TI405/DL405 (Direct Logic 405) PLC via a Facts Engineering F4-SLV-TW module using TIWAY Local Line. The F4-SLV-TW is supposedly 100 percent compatible with a standard TIWAY NIM. The system seems to work OK except for a GENERAL ERROR flagged whenever more than 14 V memory registers are read by Citect.

It would be appreciated if you could look at this configuration and let me know if it is 100 percent compatible with the Citect TIWAY driver?

 

Solution:
This hardware solution you have described seems to be not 100 percent compatible with the existing Citect TIWAY driver. This problem is that the NIMs you are using cannot service as large a request as the standard TI NIMs, so whenever Citect tries to read more than 14 registers these NIMs return an error. The max request size for Tiway can be modified in Citect so that it will be compatible with these modules or NIMs.

Modify the TIWAY entry in the C:\CITECT\BIN\PROTDIR.DBF file as follows:

TAG   FILE  BIT_BLOCK MAX_LENGTH OPTIONS
TIWAY TIWAY 224       224         0x14f

Next add the following parameter to the Citect.INI file.

[TIWAY]
MaxBits=224

In some cases you may also need to set the following parameter to slow down the Citect requests to the PLC

[TIWAY]
MaxPending=2 (or even 1 to make it slower again)

 
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