Pisonics PS7400 vs Endress+Hauser Liquiphant FTL51 — Tuning fork density meter comparison
PS7400 and the Endress+Hauser Liquiphant FTL51 are both piezo-driven tuning-fork density meters. This table compares them on measurement parameters, wetted materials, hazardous-area approvals, lead time and local service.
Feature comparison
| Feature | Online tuning fork density meter | Endress+Hauser Liquiphant FTL51 |
|---|---|---|
| Measurement principle | Piezo-driven vibrating tuning fork | Piezo-driven vibrating tuning fork |
| Density accuracy | ±0.002 g/cm³ | ±0.002 g/cm³ |
| Repeatability | ±0.001 g/cm³ | ±0.001 g/cm³ |
| Process temperature | -40 – 150 °C (high-temperature variant to 250 °C) | -50 – 150 °C (high-temperature variant available) |
| Process pressure | ≤ 4 MPa (high-pressure variant) | ≤ 100 bar |
| Viscosity tolerance | ≤ 1,000 cP | ≤ 10,000 mPa·s |
| Insertion length | 100 / 150 / 200 / 300 / 400 mm | 150 – 6000 mm (custom) |
| Wetted materials | 316L / Titanium / Hastelloy / Monel / PTFE coating | 316L / Alloy C22 / Alloy C276 / tantalum / coatings |
| Wear-resistant fork | Tungsten-carbide tip standard (slurry-optimised) | ECTFE coating optional |
| Process connection | Flange / sanitary clamp / threaded | Flange / clamp / threaded |
| Output signals | 4–20 mA + Modbus + HART | 4–20 mA + HART + PROFIBUS PA + FOUNDATION Fieldbus |
| Hazardous-area approval | Ex d IIC T6 (optional — confirm certifying body for your market) | ATEX / IECEx / FM / CSA |
| Typical lead time | 4 – 6 weeks | 8 – 14 weeks |
| Local service | Direct from the manufacturer in China | Overseas HQ with agents in China |
Competitor parameters cited from Endress+Hauser Liquiphant FTL51 datasheet.
Takeaway
The Liquiphant family is the European design benchmark for tuning-fork density measurement, with the widest approval coverage in this comparison — ATEX, IECEx, FM and CSA — and the broadest fieldbus support. If your specification names one of those schemes, or the plant is standardised on PROFIBUS PA or FOUNDATION Fieldbus, that decides it.
PS7400 competes on three specific things rather than on headline accuracy, which is comparable between the two. First, the tungsten-carbide fork tip is standard rather than an optional coating, which matters on abrasive slurry. Second, lead time is roughly half. Third, service and spares come direct from the manufacturer rather than through an agent layer.
Where the FTL51 is clearly ahead: insertion lengths to 6000 mm, viscosity tolerance an order of magnitude higher, and the approval portfolio. Confirm the certification scheme the PS7400 carries against the one your market recognises before treating the hazardous-area rows as equivalent.