Reading Arrays and Strings from a Siemens PLC
Reading arrays
The image below shows the data that will be read from a Siemens PLC.
Addresses in the Siemens Client module in N3uron will have the following format:
Siemens | N3uron | |||
| Name | Data Type | Offset | Address | Data Type |
| int01 | Int | 0.0 | db102:00 | Int16 |
| arr01[0] | Int | 2.0 + 0.0 = 2.0 | db102:02 | Int16 |
| arr01[1] | Int | 2.0 + 2.0 = 4.0 | db102:04 | Int16 |
| arr01[2] | Int | 2.0 + 4.0 = 6.0 | db102:06 | Int16 |
| arr01[3] | Int | 2.0 + 6.0 = 8.0 | db102:08 | Int16 |
| arr01[4] | Int | 2.0 + 8.0 = 10.0 | db102:10 | Int16 |
| arr01[5] | Int | 2.0 + 10.0 = 12.0 | db102:12 | Int16 |
| arr01[6] | Int | 2.0 + 12.0 = 14.0 | db102:14 | Int16 |
| arr01[7] | Int | 2.0 + 14.0 = 16.0 | db102:16 | Int16 |
| arr01[8] | Int | 2.0 + 16.0 = 18.0 | db102:18 | Int16 |
| arr01[9] | Int | 2.0 + 18.0 = 20.0 | db102:20 | Int16 |
| float01 | Real | 22.0 | db102:22 | Float32 |
| arr02[0] | Sint | 26.0 + 0.0 = 26.00 | db102:26 | Int8 |
| arr02[1] | Sint | 26.0 + 1.0 = 27.00 | db102:27 | Int8 |
| arr02[2] | Sint | 26.0 + 2.0 = 28.00 | db102:28 | Int8 |
| arr02[3] | Sint | 26.0 + 3.0 = 29.00 | db102:29 | Int8 |
| arr02[4] | Sint | 26.0 + 4.0 = 30.00 | db102:30 | Int8 |
| arr02[5] | Sint | 26.0 + 5.0 = 31.00 | db102:31 | Int8 |
| arr02[6] | Sint | 26.0 + 6.0 = 32.00 | db102:32 | Int8 |
| arr02[7] | Sint | 26.0 + 7.0 = 33.00 | db102:33 | Int8 |
| arr02[8] | Sint | 26.0 + 8.0 = 34.00 | db102:34 | Int8 |
| arr02[9] | Sint | 26.0 + 9.0 = 35.00 | db102:35 | Int8 |
| float02 | Real | 36.0 | db102:36 | Float32 |
The offset for each tag in N3uron is the result of the sum of the array offset and the offset of each element within the array.
Considerations for Using Ethernet/MPI Converters
Most extended MPI to Ethernet converters use a rack and a slot number for addressing processes. These elements are directly converted into the MPI address. For example, in order to access the MPI address 2, you would need to use the value 0 as the rack number and 2 for the slot number on the converter side. For precise assignment, please refer to the manufacturer's documentation for the converter. The table below provides the most common address assignments for these types of converters.
| MPI | Rack | Slot | TSAP |
| 0 | 0 | 0 | 0200 |
| 1 | 0 | 1 | 0201 |
| 2 | 0 | 2 | 0202 |
| ... | |||
| 31 | 0 | 31 | 021F |
| 32 | 1 | 0 | 0220 |
| 33 | 1 | 1 | 0221 |
| ... | |||
| 63 | 1 | 31 | 023F |
| 64 | 2 | 0 | 0240 |
| 65 | 2 | 1 | 0241 |
| ... | |||
| 95 | 2 | 31 | 025F |
| 96 | 3 | 0 | 0260 |
| 97 | 3 | 1 | 0261 |
| ... | |||
| 126 | 3 | 30 | 027E |