Vaisala LT31 - Mounting and Connecting Optional TERMBOX-1200 (Junction Box)

Chapter 4 _______________________________________________________________ Installation
VAISALA ______________________________________________________________________ 127
Mounting and Connecting Optional
TERMBOX-1200 (Junction Box)
TERMBOX-1200 enables a separate connection of the underground
cables and incorporates enhanced overvoltage protection. The
TERMBOX is to be mounted below the interface unit enclosure and
enables short cable ways between foundation and cable feed-throughs.
WARNING
The AC power must be switched off until all power line wiring is
finalized.
1. Open the TERMBOX-1200 cover plate.
2. Take the screws and the grounding cable out of the box.
3. Connect a short grounding cable (4 mm
2
) to grounding clamp at the
left bottom side of the box. See Figure 82 on page 121.
4. Screw the box onto the receiver mast below the interface unit. Use
screws from the delivery and hex socket driver size 5.
5. Connect the grounding cable carefully to the grounding bolt at the
base plate below the box. The wrench size is 17. See Figure 82 on
page 121.
6. Use a short 3-conductor power cable (3 x 1.5 mm
2
) with free wire
ends. Connect this power cable to the corresponding terminals
inside the TERMBOX. Use a fitting cable feed-through.
CAUTION
Double-check that the AC power is switched off.
No voltage must be detected at the end of the underground power cable.
7. Connect the respective data terminals of the interface unit with the
recommended communication cable type, see section Cable
Selection on page 73. Prepare a cable of sufficient length to
interconnect the interface unit with the respective terminals inside
the TERMBOX.
8. Route the underground cable through a fitting cable feed-through
and connect the power lines carefully.
9. Proceed the same way with the underground communication cable
for the connection to the host computer system.
10. Tighten the cable feed-through carefully and close the cover plate.
The receiver interface unit is equipped with the master CPU LTC212.
This CPU is responsible for communication with all intelligent units
within the LT31 system and for the communication with the host