I. Installation Precautions

1. Probe Installation Requirements

  • Position selection: Do not install in the feed area to avoid interference from medium impact.
  • The distance between the probe and the container wall must be ≥50 mm, and the distance from the container bottom must be ≥10 mm to avoid capacitance interference.
  • In stirred tanks, maintain a safe distance from the agitator to avoid mechanical damage.
  • When lateral loads exist, a rod probe with a grounding tube must be used (Figure 4.2.1).

  • Support device (mandatory when length >1 m):
  • Fully insulated probes can be mounted on conductive/non-conductive supports; partially insulated probes require insulation of the uninsulated end.
  • Support spacing: the lowest support is 300 mm from the probe end, and intermediate support spacing is L/2 (Figure 4.2.2).

2. Process Connection and Sealing

  • Threaded installation (G½/G¾/G1/G1½):
  • Use elastic fiber sealing rings (chemical resistant), and torque must be controlled according to specifications (e.g., G½ ≤80 Nm).
  • Taper threads (NPT) require conductive sealing material to avoid insulation interference.
  • Flange/clamp installation:
  • Sealing rings must withstand process temperature and pressure (PTFE-lined flanges require spring washers).
  • Regularly check screw tightness (recommended torque 60–100 Nm).

3. Housing Adjustment and Sealing

  • Housing rotation: It can be rotated 270° according to the cable entry position. For outdoor installation, the cable must be bent downward and secured with cable ties (waterproof).

  • Sealing protection:
  • Do not use mineral oil-based grease on O-rings (damages the seal).
  • After installation, confirm that the protective cover and cable gland are fully sealed (waterproof and dustproof).

4. Special Working Condition Handling

  • Non-conductive media (conductivity <1 μS/cm):
  • A grounding tube must be used, and the minimum probe length is calculated according to the formula (see Section 4.4).
  • Separate housing:
  • The cable length between the probe and the housing must be ≤6 m. When routed through a wall, it must be isolated from the process connection.
  • When installing the wall mounting bracket, it must be pre-positioned as a drilling template (Figure 4.5.2).

II. Wiring Precautions

1. Safety Preparation

  • Pre-power inspection:
  • The supply voltage must match the nameplate (12–36 VDC in non-hazardous areas, 12–30 VDC in intrinsically safe areas).
  • Disconnect power before operation. In hazardous areas, the Safety Guide (XA document) must be observed.

2. Equipotential and Grounding

  • Equipotential connection:
  • The cable shield on the sensor side must be grounded at one end (for hazardous areas).
  • The housing grounding terminal (T13/F13, etc.) must be reliably connected to the plant grounding system (Figure 5.1.1).
  • Cable specifications:
  • Use shielded instrument cable (cross-section 0.5–2.5 mm²).
  • When equipotential bonding is implemented, the shield can be grounded at both ends to optimize immunity (EMC compliant with NAMUR NE21).

3. Terminal Assignment and Connection

  • Two-wire wiring:
  • Terminal assignment: brown wire (+), blue wire (–) (Figure 5.2.2).
  • HART communication requires an external 250Ω resistor (if not integrated in the power supply unit).
  • M12 connector: Wiring can be done without opening the cover (Figure 5.1.4).

4. Special Requirements for Hazardous Areas

  • Cable gland selection: Only specified explosion-proof cable glands may be used (see Section 5.1).
  • Post-wiring inspection:
  • Confirm that the terminal sequence is correct.
  • The cable gland is properly sealed, and the housing protective cover is fully tightened.
  • After power-on, a flashing green LED indicates normal operation.

III. Key Points Related to Commissioning and Maintenance

  • Calibration prerequisites: When the medium conductivity is <100 μS/cm, the tank wall distance is <250 mm, or a custom range is required, recalibration is mandatory (Section 7.3).
  • Functional safety test (Position 6): After startup, a 4–22 mA ramp signal is output (about 40 seconds), and coordination with the process side is required (Section 7.2.8).
  • Maintenance warning: For explosion-proof instruments, only original spare parts are allowed. After repair, the calibration values must be transmitted via the DAT module (Section 10.3).