Appendix

Updated on 23 Feb 2024
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Reading Arrays and Strings from a Siemens PLC

Reading arrays

The image below shows the data that will be read from a Siemens PLC.

Figure 15- Data block

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.

Figure 16- Final addresses

Considerations for Using Ethernet/MPI Converters

Most extended MPI to Ethernet converters use a rack and a slot number for addressing processes. These elements aredirectly 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 theconverter 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

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Introduction

Table of contents

Reading Arrays and Strings from a Siemens PLC
Considerations for Using Ethernet/MPI Converters