NewTrend · Liquid level control relay
Product overview
NewTrend RL8-01 monitors liquid between minimum and maximum electrode levels in wells, tanks, basins and reservoirs. Its sensitivity potentiometer adjusts the electrode-circuit threshold from 5 to 100 kilohms. The fixed two-level control follows the original changeover-contact timing diagram. It uses AC/DC 24-240V and provides one SPDT output rated 10A AC-1 in an 18mm DIN-rail module.
Technical selection summary
| Model | RL8-01 |
|---|---|
| Function | Two-level electrode control |
| Control supply | AC/DC 24-240V, 50-60Hz |
| Supply terminals | A1-A2 |
| Power input | Maximum 2VA |
| Supply tolerance | -15% to +10% |
| Electrode terminals | Max, Min and C |
| Sensitivity (input resistance) | Adjustable 5-100kΩ |
| Electrode voltage | Maximum AC 5V |
| Probe current | AC below 0.1mA |
| Response time | Maximum 400ms |
| Mechanical setting accuracy | ±10% |
| Maximum probe-cable length | 800m at 25kΩ sensitivity; 200m at 100kΩ |
| Maximum probe-cable capacitance | 400nF at 25kΩ sensitivity; 100nF at 100kΩ |
| Output contacts | 1 SPDT; 11-12-14 |
| Contact rating | 10A, AC-1 |
| Switching voltage | 250VAC / 24VDC |
| Minimum DC breaking power | 500mW |
| Output indication | Red LED |
| Mechanical life | 10,000,000 operations |
| Electrical life (AC-1) | 100,000 operations |
| Reset time | Maximum 200ms |
| Temperature coefficient | 0.05%/degree C at 20 degrees C |
| Operating temperature | -20 to +55 degrees C |
| Storage temperature | -35 to +75 degrees C |
| Mounting | DIN rail to EN/IEC 60715; 18mm module |
| Protection | IP40 front panel; IP20 terminals |
| Operating position | Any |
| Overvoltage category /pollution degree | III / 2 |
| Maximum conductor size | Solid: 1 x 2.5mm² or 2 x 1.5mm²; with sleeve: 1 x 2.5mm² (AWG 12) |
| Terminal tightening torque | 0.8Nm |
| Body dimensions | 90 x 18 x 64mm |
| Weight | 70g |
| Referenced standard | EN 60255-1 |
Operation
- Connect the common, minimum and maximum electrodes to C, Min and Max according to the original two-level diagram. A1-A2 supplies the relay.
- The output contact changes state at the minimum and maximum levels and retains its state while the level remains between the probes, as shown in the RL8-01 timing diagram.
- Set the sensitivity potentiometer for the liquid and probe-cable conditions. The RL8-01 front panel has one sensitivity control.
Typical applications
- Two-level liquid monitoring in tanks, wells and reservoirs
- Pump contactor control between minimum and maximum level probes
- Electrode-based level supervision in DIN-rail control panels
View or download RL8-01/02 liquid-level control catalogue (PDF)
Product reference images and drawings
Original specifications, two-level wiring and panel diagrams
Original RL8-01/02 timing and dimension drawings
Use the RL8-01 two-level wiring and timing diagram. Select the external contactor circuit to suit the required filling or draining action. Keep probe-cable length and capacitance within the sensitivity-dependent limits. The separate RL8-02 selector and timing-knob functions in the shared catalogue apply to RL8-02. Installation and wiring must be performed by qualified electricians.
