Installing into process - MGP261 - MGP262

MGP260 Series Installation and Safety Guide

Document code
Document type
User guide
Steps 1 … 7 steps refer to illustrations 1 … 7 in the beginning of the document.
The following tools are required when installing:
  • Adjustable wrench (or a similar suitable tool) for turning the tightening nut
  • Allen keys:
    • 5 mm (3/16 in) for tightening flange
    • 2.5 mm (3/32 in) for strain relief clamps
  • Input and output cables for wiring
  • Cable glands and plugs for unused lead-throughs (as required in your application)
  • Small slotted screwdriver for screw terminals
  • PTFE tape (wide) for the probe threads
Warning Before starting the installation, make sure that your installation site matches the Ex classification of the MGP260 series probe and the requirements listed in Using MGP260 series probes in hazardous locations.
  1. Attach cable glands (not provided by Vaisala) to the wiring lead-throughs as required. Note the cable gland requirements listed in Guidelines for safe use in hazardous conditions.
    • Use an M16x1.5 gland for the external (Ex ia) sensor input wiring.
    • Use 1 or 2 M20x1.5 glands for wiring the 4 … 20 mA analog output, power supply input and RS-485 terminals (as required in your application).
    • Seal unused lead-throughs.
  2. Apply PTFE tape on the probe threads.
    • Inspect the threads and remove any possible dirt. Note that the edges may be sharp.
    • Wrap 2-3 revolutions of tape in the direction of the thread spiral, starting from the first thread. Keep the edge of tape parallel to the face of the thread while wrapping.
    • Do not tape beyond the first thread or leave loose tape hanging.
  3. Insert the probe into the 1.5" female NPT installation port and rotate it clockwise until it sits firmly in the port. Do not tighten the probe to full tightness, only enough to keep it securely in place when wiring.
    CAUTION The correct thread type in which to install MGP260 probes is 1.5" female NPT. Installing into any other thread type can damage the equipment and compromise the leak tightness of the connection. If unsure, verify the thread type with a 1.5" NPT thread gauge.
    CAUTION Rotating the probe open after it has been installed into the port can tear the PTFE tape. Only adjust the position of the probe in the installation port by tightening.
    1. Note that the pressure compensation input must be set up in order to receive accurate measurements. An example of an external measurement instrument placement is shown in this illustration. For pressure input options, see Pressure compensation input options.
  4. Open the captive screws on the connection box flange with a 5 mm (3/16 in) Allen key. After loosening the captive screws, pull the connection box cover off to access the wiring terminals.
    If necessary, use a wrench to hold the probe in place by gripping the tightening nut.
    CAUTION Connect or disconnect only de-energized wires. Never open the connection box in an explosion hazardous area when the device is energized.
  5. Lead the wiring cables through the cable glands of the connection box, and then connect the input, output, and power supply wiring as required in your application. The wiring diagram in this guide shows an example of wiring the device when all inputs and outputs are used.
    • 5A: External pressure or temperature sensor input wiring (Ex ia): route the cable to the terminal through the M16x1.5 lead-through and through the strain relief cable clamp above the component board.
    • 5B: Analog output, power supply input and RS-485 wiring: route the cables to the terminals through the M20x1.5 lead-throughs (1 or 2) and through the strain relief cable clamp below the component board.

    After connecting the wiring, adjust cable length and fasten the cables with the strain relief clamps.

    CAUTION The Ex ia external sensor input wiring (5A) must be kept separate from the analog output, power supply, and RS-485 wiring (5B). Always use separate cables on each side of the metal barrier.
  6. Close the connection box and tighten the captive Allen screws on the connection box flange. Tighten the cable glands, and then tighten the probe to final tightness on the installation port by turning the tightening nut with a 50 mm (1.97 in) wrench.
  7. Connect the grounding terminal to the grounding rail with a ≥ 4 mm2 wire. In ball valve installations, lock the valve handle in the open position with the safety pin.
    When done, switch on the power supply input.