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SynopsisWhen writing data to certain data types via the Kepware OPC Server, the associated tag will be set to zero.
SummaryThere is a known issue with the Kepware OPC Server writing to certain data types. When attempting to write to certain data types with the DTU, the tag in the PLC would be set to zero. This behavior has been seen with GE Fanuc and Allen-Bradley PLCs, though it could apply to others.DiscussionThe fix for this issue is to convert the data type of the affected tags from unsigned to a comparable signed data type. To modify the data types, please follow the table below:
| Data Type | Status | Description |
| Boolean | Works | Single bit data On or Off |
| Char | N/A | Signed 8 bit data |
| Byte | Fails | Unsigned 8 bit data |
| Short | Works | Signed 16 bit data |
| Word | Fails | Unsigned 16 bit data |
| Long | Works | Signed 32 bit data |
| DWord | Fails | Unsigned 32 bit data |
| Float | Works | 32 bit real value IEEE format |
| Double | N/A | 64 bit real value IEEE format |
| String | Works | Null terminated ASCII string |
| BCD | Fails (interpreted as Word) | Two byte-packed BCD value range is 0-9999 |
| LBCD | Fails (interpreted as DWord) | Four byte-packed BCD value range is 0-99999999 |
Additional InformationPosted: 3/13/2008
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