Magnet and sensor fitting, socket and pinout, menus, gypsy circumference table and troubleshooting for the Lofrans Thetis 5003 wired hand-held chain counter and windlass control.

Technical Data
| Thetis 5003 | |
|---|---|
| Power supply | from 12 to 24 Vdc |
| No-load current intake | min. 5 mA – max 40 mA |
| Protection rating | IP67* (IP68 plug & socket) |
| Operative temperature | -10 : +60 |
| Graphic display | 128 x 64 pixels |
| Max. chain length | 999 metres – 999 feet |
| Size (mm) | 155 x 65 x 45 (general dimensions drawing: 154 x 58 x 38 mm) |
| Net weight (g) | 370 |
| Compliance | EN 55032: 2015; EN 55024: 2010+A1: 2015 |
*Excluding the cable connection zone. The size in the specification table and on the dimension drawing differ (as printed).
- In the box: Thetis 5003 hand-held chain counter, 6-pole connector (female plug), magnetic sensor, magnet, horizontal-shaft windlass sensor support, cradle with 2 screws, manual.
Magnet & Sensor
- Some windlasses come with sensor and magnet already fitted (chain counter setting): skip this step.
- Drill a 7 mm (9/32") hole, 12.5 mm (31/64") deep, in a gypsy tooth outside the chain's path; on horizontal-shaft windlasses, in the outer circumference of the gypsy.
- Make sure the protruding magnet cannot hit the base or sensor as the gypsy turns.
- Insert the metal part of the magnet, leaving the protected part about 2 mm proud; fix with two-component epoxy for metals or silicone, marine grade.
- Horizontal-shaft windlasses: drill a 4 mm (~3/16") hole in the cover for the sensor cable; fit support Part A with its two screws over the O-ring; cut Part C to length; glue Part C and the sensor in place.
- Sensor to magnet distance between 2 mm and 10 mm (5/64" to 25/64").
Chain Counter & Socket
- Easy to read, out of direct sunlight; secure the hand-held in its cradle with the two screws.
- Socket: one 20 mm (~13/16") hole; secure the female plug with its back locking nut on a dashboard no thicker than 10mm, gasket between plug and dashboard, rear kept dry.
- Wires at least 1.5 mm²; 5 A fast fuse on the battery positive; do not power it from the engine battery set.
- Series resistor recommended for a sensor cable longer than 5m.
- Distances: 30 cm (~1 Ft) from the compass, 50 cm (~1.5 Ft) from radio equipment, 2 metres (~6.5 Ft) from radio transmitters and from the radar beam.
6-Pole Connector
| Pin | Signal (p. 6) | Signal (wiring diagram) |
|---|---|---|
| 1 | − battery | − battery |
| 2 | + battery | + battery |
| 3 | DOWN command | DOWN command |
| 4 | UP command | UP command |
| 5 | Magnetic sensor | Magnetic sensor |
| 6 | Buzzer | N.C. |
The wiring diagram shows the Bulgin connector: UP and DOWN to the windlass control box B2/B3 with C as common, sensor back from the gypsy, 5A fuse and switch on + battery, optional external remote switches in parallel.
Operation & Menus
- Three keys: ON (display on, enables the other keys, enters and confirms menus), UP (hoist) and DOWN (cast). Releasing UP or DOWN stops the windlass.
- Main page shows STATUS, SPEED (m/min or ft/min), COUNT (chain out), MONITORING (instrument and boat supply voltage) and direction/fault icons.
- Hold ON for six seconds for the setting menu; DOWN/UP to move, ON to select and confirm, Exit to go back.
| Menu | Items |
|---|---|
| Measure | Reset Measurement (to 0.0); Units (feet/inches or metres/centimetres); Exit |
| Alarms & Function | Up Alarm (windlass stops at a set height: 1.0 – 1.5 – 2.0…5.0 metres or feet; release UP to continue); Load Default (factory reset, only after programming errors) |
| Settings | Contrast; Back Light (default 120 seconds); Light Time (backlight on-time, default 30 seconds); Keyboard Beep |
| Language | Italian, English, French, German, Spanish, Greek |
| Sensor Calibration | Sensor Selection STD; Gypsy circumference (default 33 cm) |
| Tests | Software Version, Operating Time, Sensor Test, LCD Test |
The Back Light and Light Time descriptions appear swapped in the manual (as printed).
Table 1 – Standard Series Sensor (magnet and sensor on the gypsy)
| Chain type | Number of recesses (R value) | Gypsy circumference (G value), cm | Gypsy circumference, inches |
|---|---|---|---|
| 6mm ISO 4565 / DIN 766 | 5 | 18,0 | 7,1 |
| 6 | 21,6 | 8,5 | |
| 9 | 32,4 | 12,8 | |
| 10 | 36,0 | 14,2 | |
| 7mm ISO 4565 | 6 | 25,2 | 9,9 |
| 9 | 37,8 | 14,9 | |
| 8mm ISO 4565 / DIN 766 | 5 | 24,0 | 9,4 |
| 6 | 28,8 | 11,3 | |
| 7 | 33,6 | 13,2 | |
| 8 | 38,4 | 15,1 | |
| 10mm ISO 4565 | 5 | 30,0 | 11,8 |
| 6 | 36,0 | 14,2 | |
| 7 | 42,0 | 16,5 | |
| 10mm DIN | 5 | 28,0 | 11,0 |
| 6 | 33,6 | 13,2 | |
| 7 | 39,2 | 15,4 | |
| 12mm ISO 4565 & 13 DIN 766 | 5 | 36,0 | 14,2 |
| 6 | 43,2 | 17,0 | |
| 13 DIN 764 | 5 | 45,0 | 17,7 |
| 14 pitch 42mm | 5 | 42,0 | 16,5 |
| 5/16 HT | 7 | 36,7 | 14,4 |
| 3/8" BBB | 7 | 38,8 | 15,3 |
| 3/8" P.C. | 6 | 44,2 | 17,4 |
| 1/2 BBB | 6 | 40,8 | 16,1 |
| 1/2 HT | 5 | 40,4 | 15,9 |
Enter the gypsy circumference in the Sensor Calibration menu; factory setting 33,0. Values are indicative; for an accurate figure the manual refers to a formula based on the R value and the chain internal length (printed incompletely as "(G value) = * R value* Chain Internal Length").
Troubleshooting
| Display | Fault | Corrective action |
|---|---|---|
| No Sensor | UP or DOWN pressed but no signal from the magnetic sensor for more than 5 seconds | Check the sensor connections and the sensor itself (replace if faulty); check sensor and magnet position and their distance; check the electrical installation and the windlass. |
| Low Voltage | Supply voltage below 10Vdc | Check the battery charge and the electrical system. |
Warranty: 2 years.
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