An inline Turner Designs fluorometer that measures PTSA fluorescent tracer.
PTSA in parts per billion — see Fluorescence (PTSA).
The LD2 is the Turner Designs Little Dipper 2. The PTSA version is part number 2820-000-A; a fluorescein version (2820-000-F) also exists.
| Dynamic range | Under 1 to 300 ppb PTSA, typical |
| Sensitivity | Under 1 ppb, typical |
| Linearity | 0.99 r² over the dynamic range |
| Optics | LED light source, photodiode detector |
| Temperature compensation | Turner does not list any in the probe; it gives a PTSA coefficient of −0.00126 /°C (exponential) for correcting readings to a reference temperature |
| Output | 4–20 mA |
| 4–20 mA default scaling | Linear, 0–200 PPB |
| Factory adjustment | 200 ppb PTSA gives 18.0–19.5 mA; changing the range needs Turner’s calibration cable kit (P/N 2820-505) |
| Supply | 8–30 VDC; 0.88 W at 12 VDC, 1.0 W max |
| Warm-up | 5 seconds after power-up |
| Connector and cable | Keyed connector with locking collar; 5 ft cable (P/N 021-2800) with four bare leads |
| Wetted materials | Type I rigid injection-moulded PVC (probe and mounting tee), optical window |
| Process connection | Mounting tee with 1 in NPT threads, supplied |
| Pressure and temperature limits | Tee rated to 100 psi dynamic pressure; 0–50 °C operating |
Wire colors:
| Wire | Function |
|---|---|
| Red | Supply, 8–30 VDC + |
| Black | Supply ground, 0 V |
| Orange | 4–20 mA signal out (“A”) |
| Brown | 4–20 mA return (“Common”); Turner’s wiring guide lists it as Green/Brown |
The black supply ground and the brown 4–20 mA return are not common. Do not connect them to the same point, and do not let bare leads touch each other or a conductive surface.
Hydrochloric acid is hazardous. Only qualified personnel should handle it.
Wiring and configuration live with each controller: