Normally length is 1 for 1 item.
Offset is the byte from first value.
Read the built in help (explains it better)
Also, try the built in demos (CTRL+I)
Lastly, it pays to generate a table for reference - to help yourself when mapping the values. E.g...
| PLC address | name | type | byte |
|---|---|---|---|
| D4000 | bladeSpeed | int16 | 0 |
| D4001 | motorA | int16 | 2 |
| D4010 | Test Value | int32 | 20 |
Basically, each PLC memory area is 2 byte value.
Example...
Demo (use CTRL+I to import)
[{"id":"5c4ec4d6f5146fc0","type":"buffer-parser","z":"766a1068.58afb","name":"","data":"payload","dataType":"msg","specification":"spec","specificationType":"ui","items":[{"type":"int16be","name":"bladeSpeed","offset":0,"length":1,"offsetbit":0,"scale":"/ 10","mask":""},{"type":"int16be","name":"motorA","offset":2,"length":1,"offsetbit":0,"scale":"/ 100","mask":""}],"swap1":"","swap2":"","swap3":"","swap1Type":"swap","swap2Type":"swap","swap3Type":"swap","msgProperty":"payload","msgPropertyType":"str","resultType":"keyvalue","resultTypeType":"output","multipleResult":false,"fanOutMultipleResult":false,"setTopic":true,"outputs":1,"x":2250,"y":1320,"wires":[["b96ee73c918f4453"]]}]
