pH ARC Sensors Modbus RTU Programmer’s Manual (EPHUM011)
2.4.5.3Reading the Minimum and Maximum Possible Physical Output Current
Start | Number of | Reg1 / Reg2 | Reg3 / Reg4 | Modbus | Read | Write |
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| function code | access | access |
4366 | 4 | Min physical | Max physical | 3, 4 | U/A/S | none |
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| output current | output current |
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| for AO1 [mA] | for AO1 [mA] |
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4494 | 4 | Min physical | Max physical | 3, 4 | U/A/S | none |
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| output current | output current |
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| for AO2 [mA] | for AO2 [mA] |
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Figure 2.4.5.3.1: Definition of register 4366 / 4494
Command: Limits AO1 | Modbus address: 4366 | Length: 4 | Type: 3 | Read | ||
Parameter: | Min limit [mA] | Max limit [mA] |
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Format: | Float | Float |
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Value: | 3.5 | 22 |
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Figure 2.4.5.3.2: Example to read the min and max output current of AO1. Min is fixed to 3.5 and Max is fixed to 22 mA (Currents above 20 and below 4 mA indicate erroneous measurements or errors).
The same values are stored in register 4494 for AO2.
2.4.5.4Reading the Minimum, Maximum and Mid Current for Measurement Value Output
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4370 | 6 |
| Min output for |
| Max output for | Mid output |
| 3, 4 |
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| U/A/S | none | ||||||
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| measurement | (bilinear) for |
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| value for AO1 |
| values for AO1 | measurement |
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| AO1 [mA] |
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4498 | 6 |
| Min output for |
| Max output for | Mid output |
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| U/A/S | none | ||||||
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| measurement |
| measurement | (bilinear) for |
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| value for AO2 |
| values for AO2 | measurement |
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Figure 2.4.5.4.1: Definition of register 4370 | / 4498 |
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Command: MinMaxMid current AO1 |
| Modbus address: 4370 | Length: 6 |
| Type: 3 | Read |
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Parameter: | Min current [mA] |
| Max current [mA] |
| Mid current [mA] |
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Format: |
| Float |
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| Float |
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| Float |
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Value: |
| 4 |
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| 20 |
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| 12 |
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Figure 2.4.5.4.2: Example to read the min, max and mid output current for measurement values for AO1. They are fixed to 4, 20 and 12 mA.
The same values are stored in register 4498 for AO2.
Note:
Mid current must always be defined. However, in linear output mode, the mid current value has no physical meaning and will not affect the 4-20 mA output.
624300/01 | page 12 / 67 |
