This document provides instructions for installing, using and maintaining Vaisala K‑Patents® Process Refractometer PR‑21‑S.
| Document code | Date | Description |
|---|---|---|
| IM‑EN‑PR21S, C | June 2021 | Model codes and specifications updated. Minor structure and style updates. |
| IM‑EN‑PR21S, B | December 2019 | Model codes, specifications updated. |
| IM‑EN‑PR21S, A | September 2019 | K‑Patents → Vaisala change, new covers. |