PyXis harmonic array integration gives a PLC or SCADA system more diagnostic context than a single overall vibration value. The controlled PyXis datasheet defines 20 frequency values and 20 associated acceleration-amplitude values for each of the X, Y and Z axes. These compact arrays let a host review important spectral components over Modbus RTU without continuously transferring raw vibration waveforms.
The integration still needs a disciplined data model. Frequency and amplitude values must remain paired by axis and array position, and the host must use the register map that matches the installed firmware for addresses, data types, scaling, units and update behaviour. Flattening the values into anonymous tags removes the relationship that makes the data useful.
PyXis harmonic array integration starts with paired data
For each measurement axis, PyXis exposes a set of frequency values and a corresponding set of acceleration amplitudes. A practical host structure therefore treats each array position as one pair:
- axis: X, Y or Z;
- pair index: the matching position in the frequency and amplitude arrays;
- frequency value: decoded with the firmware-specific data type and scale;
- acceleration amplitude: decoded from the associated position using the released units and scale;
- device context: serial number, hardware revision and firmware revision;
- host timestamp and quality: added by the PLC, gateway or historian when the block is acquired.
The datasheet identifies 20 frequency values and 20 associated amplitude values per axis. It does not define a universal interpretation for an array position independent of the matching register map. The integration should not assume that index numbers have fixed fault meanings, that the entries are always ordered the same way, or that unused positions follow a particular convention unless the released documentation says so.
Keep frequency and amplitude registers together
A useful harmonic point is the combination of frequency and amplitude. Reading or storing only one side of the pair creates ambiguous data. If the master polls the frequency block and amplitude block at widely separated times, a changing machine state may also make the combined record difficult to interpret.
Build one acquisition transaction in the host
Use the firmware-matched register map to identify the valid input-register ranges and supported Modbus function. PyXis uses Modbus RTU and supports input-register reads for identity, vibration, harmonic, condition, rotational, diagnostic and prognostic values. Exact addresses, word counts and data types belong to the released map, not to a generic template.
Where the map and master allow, acquire the related frequency and amplitude ranges in a compact polling sequence and assign one host timestamp to the completed set. If the release documentation defines snapshot, coherency or update rules, follow them. If it does not, do not claim that all array values are an atomic sample; record the read interval and evaluate whether machine speed or load can change materially during that interval.
Reject incomplete sets deliberately
A timeout halfway through the array should not silently produce a mixed record containing old and new values. The PLC or gateway can mark the completed set as invalid, retain the last known valid set with an explicit stale flag, or retry according to the project’s communication policy. The correct choice depends on how the data will be used, but stale information must not look current.
A PLC tag model that remains maintainable
Controllers that support arrays and user-defined types can represent each axis as 20 records containing frequency and amplitude. Controllers with a flat tag model can still use a consistent naming convention, for example:
PyXis_X_Harmonic_01_FrequencyPyXis_X_Harmonic_01_AmplitudePyXis_X_Harmonic_Set_ValidPyXis_X_Harmonic_Set_Timestamp
Repeat the structure for Y and Z rather than mixing axes into one undifferentiated list. Keep the device identity and register-map revision alongside the tag definition so a later firmware change triggers an engineering review instead of an unnoticed scaling error.
The PLC does not need to retain every historical set. It can expose the current paired arrays, the acquisition status and selected derived comparisons to SCADA, while a historian or maintenance platform stores longer-term records.
Historian storage for changing spectral components
Two storage patterns are common. A wide record stores all 20 frequency/amplitude pairs for an axis in one timestamped row. A long record stores one row per axis and pair index. The long form is usually easier to query when the dominant frequencies change position; the wide form can be convenient for transferring a complete set as one payload.
Whichever model is selected, preserve:
- timestamp and communication quality;
- axis and pair index;
- frequency and acceleration amplitude with explicit engineering units;
- device serial number and firmware revision;
- machine operating state, speed and load where available;
- machine profile, filter settings and baseline reference used at the time.
This context prevents a maintenance user from comparing two harmonic sets that were captured under different speeds, loads, filters or mounting conditions and treating the difference as a confirmed fault.
Relate harmonic data to running speed carefully
PyXis also exposes rotational context such as RPM, tachometer quality, speed state and 1X order according to the firmware profile. Those values can help a supervisory application relate frequency components to running speed, but the host should first confirm that the speed information is valid and that the scaling and enumerations match the installed firmware.
A component near running speed, a multiple of running speed or an expected gear-related frequency can guide investigation. It is not a universal diagnosis by itself. Machine geometry, load, mounting stiffness, process excitation and trend history remain part of the engineering assessment.
The PyXis machine profile configuration guide explains how motor frequency, gear ratio, tooth count and bearing geometry provide the machine context needed for asset-specific interpretation.
Compact spectral data has defined limits
The harmonic arrays are designed for compact spectral review over an industrial serial link. Twenty frequency/amplitude pairs per axis are not the same as a continuously streamed raw waveform or a complete high-resolution spectrum. Applications that require waveform inspection, phase analysis, specialised high-frequency techniques or laboratory-grade diagnostics may need additional instrumentation.
The controlled datasheet also states that sample and update timing depend on the firmware profile and enabled analysis functions. The host should therefore avoid inventing a fixed refresh rate. Confirm timing in the release note, set the Modbus poll interval accordingly, and include stale-data logic.
Similarly, do not infer signedness, decimal position, units, entry ordering or unused-entry behaviour from a register name. Those details must come from the released PyXis register map.
Acceptance tests before the data reaches SCADA
- Read identity. Confirm device code, serial number, hardware revision and firmware revision against the asset record.
- Match the map. Use the Modbus register map and firmware note for the installed release.
- Verify decoding. Check data type, word order, scale and engineering units for both frequency and amplitude values.
- Preserve pairing. Prove that every frequency entry remains associated with the same-axis amplitude entry at the matching position.
- Check X, Y and Z separately. Compare the host structure with the recorded physical sensor orientation.
- Test a stable operating condition. Acquire repeated sets at steady speed and load, then check plausibility and repeatability.
- Change operating state deliberately. Where safe, confirm that the supervisory record captures the new state without mixing incomplete blocks.
- Interrupt communications. Verify that the PLC, gateway and historian mark the harmonic set stale or invalid according to the project policy.
- Retain the release record. Store firmware, register-map revision, filters, machine profile and commissioning date with the tag database.
Who should use the harmonic arrays
This interface suits machine builders, system integrators and maintenance teams that need more spectral context than an overall vibration trend but want to keep Modbus traffic manageable. It is particularly useful when selected condition information must pass through a PLC or gateway into SCADA, a historian or a CMMS workflow.
Review the Tachyonic product range, compare options with the product selector, and retain the matching files from the technical resources before freezing the tag design.
Planning a PyXis data integration? Send the firmware/register-map revision, controller or gateway model, required axes, poll interval, historian structure and machine-speed context for an engineering review.
Technical basis: PyXis 222x Series datasheet TTN-DS-2026-002, Rev 08, issued 22 July 2026. Verified capabilities include 20 frequency values and 20 associated acceleration-amplitude values per axis, Modbus RTU access and compact spectral review without continuous raw-waveform transfer. Exact addresses, data types, scaling, units, ordering and update behaviour require the matching firmware register map and release note.
Featured visual: “Engineer Testing Sound System” by ThisIsEngineering, via Pexels, used under the Pexels licence. The photograph illustrates engineering data analysis and does not depict the PyXis user interface.
