What products are involved?
SRV – Inline Viscosity Meter | SRD – Inline Density & Viscosity Meter | DVP | DVM
What is the purpose of this article?
To explain the two calibration certificate options available for Rheonics Type-SR sensors, how they differ from product compliance certificates, and how to identify which certificate your application or auditor requires.
| Short answer: Every Rheonics sensor ships with a standard NIST-traceable calibration certificate at no extra cost. A detailed per-unit certificate (option CUS/VCAL2) is available — order it with the sensor to avoid additional charges. This article also explains how calibration certificates differ from compliance and safety certificates. |
TABLE OF CONTENTS
- 1. Standard calibration certificate
- 2. Sensor-specific calibration certificate — option CUS/VCAL2
- 3. Calibration options across the product lines
- 4. Calibration certificates vs. compliance certificates
- 5. Quick reference
1. Standard calibration certificate
Ships with every Rheonics sensor at no extra cost. It confirms that the unit has been factory-calibrated to NIST-traceable standards prior to shipment.
2. Sensor-specific calibration certificate — option CUS/VCAL2
Available on request. This is a per-unit certificate that documents:
- the NIST-traceable reference fluid used,
- the accuracy and precision achieved for that specific serial number.
| ⚠ Important — order CUS/VCAL2 with the sensor: The data is captured during factory calibration. Requesting the certificate after the sensor has shipped incurs additional charges, as the unit may need to be returned or recalibrated. Specify CUS/VCAL2 on your purchase order if your quality system or auditor requires per-sensor calibration data. |
3. Calibration options across the product lines
Both certificate options apply across the full Type-SR sensor family. The table below shows what each product measures and the calibration standard applied.
| Product | Measures | Calibration |
|---|---|---|
| SRV | Viscosity | NIST-traceable; standard 5% of reading, 1% and higher accuracy available |
| SRD | Density + viscosity | NIST-traceable density and viscosity standards |
| DVP | Density + viscosity (gas/liquids, ultra-high accuracy) | NIST-traceable; customer-specific range/accuracy on request |
| DVM | Density + viscosity (HPHT, ultra-high accuracy) | NIST-traceable; customer-specific range/accuracy on request |
Higher-accuracy and customer-specific calibrations — specifying viscosity/density range, accuracy required, and operational conditions — are ordered as options at the time of purchase.
| Systems — SLS SlurrySense, SRD MudSense, SDP Sand Detector Probe, and RPA Retractable Probe Assembly — are built around these sensors and carry the calibration certificate of the embedded sensor. |
4. Calibration certificates vs. compliance certificates
A calibration certificate documents the measurement accuracy of an individual unit. A compliance or safety certificate certifies the product's design, safety, and regulatory conformity — it is not tied to any specific serial number. All compliance certificates are available from the Rheonics Certificates page.
4.1 Hygienic and food-safety
- 3-A Sanitary Standards — sanitary design approval recognised primarily in North America for dairy, food, and beverage equipment.
- EHEDG (European Hygienic Engineering & Design Group) — hygienic design certification for food, beverage, and pharmaceutical equipment; supports clean-in-place (CIP).
- FDA food-contact materials (FCM) — confirms wetted materials are suitable for food contact.
4.2 Quality and general conformity
- ISO 9001 — Rheonics quality management system certification.
- CE marking — EU conformity, including the EMC Directive (EN 61326) and RoHS, with the EU Declaration of Conformity.
4.3 Hazardous-area approvals (Ex)
Rheonics SRV and SRD probes are intrinsically safe and approved across the major regional Ex schemes: ATEX (EU), IECEx (international), JPEx (Japan), and KCs (Korea). Full ratings, certificate numbers, and installation guidance are on the dedicated Ex articles and the Certificates page.
4.4 North America — cULus
Rheonics products are available with cULus approval, providing Nationally Recognised Testing Laboratory (NRTL) acceptance for the United States and certification for Canada. It covers two scopes:
- Ordinary Locations (OrdLoc) — general electrical product-safety listing for non-classified areas.
- Hazardous Locations (HazLoc) — for classified hazardous areas under both the Class/Division and Zone systems.
| ⚠ Note: cULus approval is newly available and may not yet appear on the public Certificates page. Contact Rheonics Support for the current cULus certificate, scope, and product-specific markings. |
5. Quick reference
| You need | Certificate |
|---|---|
| Proof the unit was factory-calibrated to NIST-traceable standards | Standard calibration certificate — included with every sensor |
| Per-unit record of reference fluid, accuracy and precision | Sensor-specific certificate, option CUS/VCAL2 — order with the sensor |
| Hygienic / sanitary design (food, dairy, beverage, pharma) | 3-A, EHEDG, FDA food-contact — see Certificates page |
| US/Canada electrical safety or classified hazardous areas | cULus (OrdLoc and HazLoc) — contact support; ATEX/IECEx/JPEx/KCs for other regions |
| EU conformity / quality management | CE (incl. EMC, RoHS) and ISO 9001 — see Certificates page |
| If you are unsure which certificate your application or auditor requires, contact Rheonics Support and we will point you to the right document. |
Further information
Calibration
- Calibration of inline process viscometer SRV in field and factory — what calibration is, why it matters, and how Rheonics performs it.
- Calibration for Type-SR sensors in field, verification and re-calibration — step-by-step field calibration procedure using reference fluids.
- Doing an air check in Rheonics sensors — how to verify whether a sensor needs recalibration.
- Measurement device (sensor) repeatability and reproducibility — understanding accuracy, precision, and R&R for Rheonics sensors.
ISO 17025 and NIST traceability
- Does Rheonics provide an ISO 17025 certificate for its sensors? — detailed explanation of the difference between ISO 17025 lab accreditation and a sensor calibration certificate, and how NIST traceability satisfies FDA and ISO 9001 requirements.
All certifications
- Rheonics certifications and compliance: overview — a single-page guide to every Rheonics certificate and approval, including Ex, cULus, EHEDG, CE, and ISO 9001.
Hygienic design
- Hygienic and sanitary process viscometer and density meter for inline installation — hygienic design features, CIP compatibility, and application guidance.
- EHEDG and 3-A — detail on the two main hygienic certification schemes and how Rheonics sensors comply.
Downloads
- Rheonics Certificates page — download all compliance and approval certificates directly.