【2025 Practical Application】How Honeywell PKS Systems Read HART Data via OPC
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1. OPC: OPC (OLE for Process Control) is an industrial automation communication protocol designed to address the issue of data exchange between devices from different manufacturers. It is based on Microsoft’s OLE/COM technology, allowing for standardized data exchange between Windows applications and industrial devices such as PLCs, DCSs, sensors, etc.
2. The HART protocol (Highway Addressable Remote Transducer) is a communication protocol widely used in the field of industrial automation. It allows digital signals to be superimposed on traditional 4-20mA analog signal lines, thereby enabling two-way communication between field devices and control systems.
3. EPKS: In Honeywell’s EPKS, the HPPA (HART Point Parameter Access) mechanism can be utilized to read data from field devices that support the HART protocol via the OPC protocol, thereby enabling easier monitoring and control of these intelligent field devices.
It is important to note that for the HART instruction set, the Universal and Common Practice instruction sets can currently only be invoked in a \"read-only\" manner, and the supported versions are HART 5, 6, and 7.
Furthermore, in essence, accessing HART through the OPC mechanism relies on device description files (DD files) to parse commands; as a result, this access is separate from ERDB’s CDA. This is why it is not possible to directly access its data in Control Builder. However, since it can be broadcasted via OPC, it can be accessed using standard OPC clients.
Another point to note is that since there are multiple Program IDs for OPC Servers in the EPKS system, if we want to use HPPA, we must select HWHsc.OPCServer5.
When adding a Group, the fastest access frequency supported by the system is 6 seconds; by default, the system uses 10 seconds as the threshold. Requests with a duration greater than 10 seconds are considered continuous access, while those with a duration less than 10 seconds are considered one-time reads.
Next, you can add Items, which are in the format of Channel.Parameter. For example: STT.Transmitor_01.longTag.
Other types of client access mechanisms follow a similar pattern, so they will not be discussed in detail here.
Finally, we can conveniently monitor its operating status through the flowchart sysStsHPPA.htm.