8. Modbus protocol
The link between the drive parameters and the communication scanner variables can be made:
-Via the display terminal (see section "6. Configuration - 6.2 Communication scanner")
-Via Modbus: Before starting the application, the PLC must first write the address tables described below.
Output variable address | Logic address | Default value |
[Scan.Out1 address] (nCA1) | 12 721 = 16#31B1 | 8501 = 16#2135 |
[Scan.Out2 address] (nCA2) | 12 722 = 16#31B2 | 8602 = 16#219A |
[Scan.Out3 address] (nCA3) | 12 723 = 16#31B3 | 0 |
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[Scan.Out4 address] (nCA4) | 12 724 = 16#31B4 | 0 |
[Scan.Out5 address] (nCA5) | 12 725 = 16#31B5 | 0 |
[Scan.Out6 address] (nCA6) | 12 726 = 16#31B6 | 0 |
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[Scan.Out7 address] (nCA7) | 12 727 = 16#31B7 | 0 |
[Scan.Out8 address] (nCA8) | 12 728 = 16#31B8 | 0 |
Input variable address | Logic address | Default value | |
[Scan. IN1 address] (nMA1) | 12 701 | = 16#319D | 3201 = 16#0C8B |
[Scan. IN2 address] (nMA2) | 12 702 = 16#319E | 8604 = 16#219C | |
[Scan. IN3 address] (nMA3) | 12 703 | = 16#319F | 0 |
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[Scan. IN4 address] (nMA4) | 12 704 = 16#31A0 | 0 | |
[Scan. IN5 address] (nMA5) | 12 705 = 16#31A1 | 0 | |
[Scan. IN6 address] (nMA6) | 12 706 = 16#31A2 | 0 | |
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[Scan. IN7 address] (nMA7) | 12 707 = 16#31A3 | 0 | |
[Scan. IN8 address] (nMA8) | 12 708 = 16#31A4 | 0 | |
Example
•Use of the "Read/Write Multiple Registers" function (request code: 23 = 16#17)
•Transmission of the request to a drive located at address 20 (16#14)
•Reading all 8 scanner input variables
•List of source parameters:
No. | Parameter | Logic | Read |
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| address | value |
1 | Status word (EtA) | 3201 | 16#0007 |
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2 | Output speed (rFrd) | 8604 | 16#1388 |
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3 | Motor current (LCr) | 3204 | 16#0064 |
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4 | Output torque (Otr) | 3205 | 16#0045 |
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•Writing the first 6 scanner output variables
•List of target parameters:
No. | Parameter | Logic | Value to |
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| address | be written |
1 | Control word (CMd) | 8501 | 16#000F |
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2 | Speed reference (LFrd) | 8602 | 16#1388 |
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3 | High speed (HSP) | 3104 | 16#1F40 |
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4 | Low speed (LSP): | 3105 | 16#01F4 |
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No. | Parameter | Logic | Read |
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| address | value |
5 | Power section AC supply voltage | 3207 | 16#00F0 |
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6 | Drive thermal state (tHd) | 3209 | 16#0065 |
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7 | Motor thermal state (tHr) | 9630 | 16#0032 |
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8 | Altivar fault code (LFt) | 7121 | 16#0000 |
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No. | Parameter | Logic | Value to |
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| address | be written |
5 | [Acceleration] (ACC) | 9001 | 16#04B0 |
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6 | [Deceleration] (dEC) | 9002 | 16#0258 |
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7 | - | 0 | 16#0000 |
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8 | - | 0 | 16#0000 |
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