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| Properties | Values | ||||||
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| Unit Name | Unit name identifying the HART device. If the Unit Address field is set to a number >100, the RediGate will poll the HART device based on its configured Unit Name (Tag). In this case, the Unit Name field should be no longer than 8 characters. If the Unit Address is <100, the RediGate will poll the HART device by its numeric address, and the Unit Name field is only used for internal identification, MQTT publishing, etc. | ||||||
| Unit Address | Unit address of the HART device on the network. Typically, the Unit Address will be 0 through 15. However, to poll by HART Tag name, set the Unit Address to a unique number greater than 100. See the Unit Name property above for instruction on configuring for Poll by Tag. | ||||||
| Protocol | Hart Unit | ||||||
| Com Retries |
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| Comm Status Holdreg |
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| Produce RBEs |
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| Poll Table |
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The |
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Poll Table references the list of Hart Command objects created elsewhere in the configuration, |
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mapping the bytes of the HART commands into RTDB register addresses. |
| Poll Table Properties | |
|---|---|
| Properties | Values |
| Command Index | Select one of the HART Commands on each row of the Poll Table. The list of HART Commands in this list is dynamic, depending on the ACE objects defined under HART Commands. |
| Comment | The Comment column is an optional field, allowing a description to be entered for each row in the table. This is only for the user and has no effect on the operation of the RediGate. |
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The definition of a HART Command within the ACE configuration requires knowledge of the command structure (Data portion only), as published by the HART Communication Foundation or manufacturer device-specific command documentation. Some Several examples are given below.
HART Command 3 – Read Dynamic Variables and Loop Current
For example, HART universal command #3 returns the loop current and up to four process variables with their engineering units codes (the 2nd, 3rd, and 4th variables are optional). Documentation for command #3 describes the following Data structure:
Request Data Bytes
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To create a HART Command definition in ACE that will read up to four process variable and the milliamp current (but discard the unit codes), a Command definition would be constructed as shown below. The minimum required RTDB configuration is also shown. This command would be scanned in the Master Channel using the Unit Address of the device (as configured in ACE) and the Poll Record number (row number of this HART Command in the device's Poll Table).
However, to as a variation on the example, to poll and store all four process variables, milliamp current, plus and the units codes into the RTDB registers, a different HART Command and additional RTDB registers would need to be defined, as shown below:
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