pH ARC Sensors Modbus RTU Programmer’s Manual (EPHUM011)
2.5Measurement
2.5.1 Definition of Measurement Channels and Physical Units
The pH ARC Sensor Modbus register structure allows the definition of 6 individual Primary Measurement Channels (PMC), and 16 individual Secondary Measurement Channels (SMC).
Bit # | Hex code | Description | Definition |
0 (LSB) | 0x000001 | PMC1 | pH |
1 | 0x000002 | PMC2 | not available |
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| not available |
4 | 0x000010 | PMC5 | not available |
5 | 0x000020 | PMC6 | Temperature |
6 | 0x000040 | SMC1 | R glass |
7 | 0x000080 | SMC2 | R reference |
8 | 0x000100 | SMC3 | R auxiliary |
9 | 0x000200 | SMC4 | E pH vs. ref |
10 | 0x000400 | SMC5 | E SG vs. ref |
11 | 0x000800 | SMC6 | E aux vs. ref |
12 | 0x001000 | SMC7 | E reference |
13 | 0x002000 | SMC8 | pH act |
14 | 0x004000 | SMC9 | T act |
15 | 0x008000 | SMC10 | not available |
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21 (MSB) | 0x200000 | SMC16 | not available |
Figure 2.5.1.1: full list of PMC1 to 6 and SMC1 to 16.
In Register 2048, the available PMC and SMC are defined for a specific pH ARC Sensors and a specific operator level.
Start | Number of | Reg1 / Reg2 |
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register | registers |
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| function code | access |
| access |
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2048 | 2 |
| Available measurement channels | 3, 4 | U/A/S |
| none |
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| PMC and SMC (bitwise set) |
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Figure 2.5.1.2: Definition of register 2048. |
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Command: Avail. PMC and SMC | Modbus address: 2048 | Length: 2 | Type: 3 | Read | |||||||
Parameter: | Avail. PMC and |
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| SMC |
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Format: |
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Value: |
| 0x06E1 |
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Figure 2.5.1.3: Example to read Reg. 2048 for Polilyte Plus ARC.
In case of operator A/U, the value 0x06E1 is returned. In other words the following PMC and SMC are available to A/U: PMC1 / PMC6 / SMC1 / SMC2 / SMC4 / SMC5
In case of operator S, the value 0x066E1 is returned. In other words the following PMC and SMC
are available to S: PMC1 / PMC6 / SMC1 / SMC2 / SMC4 / SMC5 / SMC8 / SMC9
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