Page
14 of 40
Issue 2
13/12/99
PETS-2 Crossing Telephone System
QUICKFIX INSTALLATION HANDBOOK
14
The Level Crossing Unit outer case is identical to that of the Signal Box unit. The case was
originally intended to be compatible with the space taken by two BR Signalling Relays,
although normal practise is to install the unit within an equipment room. PETS 2 retains the
environment capability to be installed into a signalling or telecommunications track-side
location cabinet. The Level Crossing Unit is sealed to IP55, and internal PCB’s (of both
units) are conformally coated for added environmental protection. The front panel
arrangement of the Level Crossing Unit is entirely different to that of the Signal Box Unit.
The Level Crossing Unit has no front panel operated buttons, and the panel is placed
further forward to allow dust & water seal to be made between the front panel and the case.
All of the internal indicators are visible through a label fitted to the front panel. Other
features are detailed below:
4.3.1 Item 1 - Connection Plate
This is identified at the left side of the photograph (Fig.2). The arrangement of connectors is
identical to that of the Signal Box, please refer to 4.2.1. However, the following important
differences should be noted:
a) A foam rubber seal is provided around the ‘D’ connectors of the Level crossing Unit to
maintain the IP55 seal
b) The Junction box of the Level Crossing Unit is different to that of the Signal Box, for
instance there is no alarm sounder in the Level Crossing Unit Junction Box.
NOTE: It is recommended that Silica Gel bags are inserted in the Level Crossing Unit case
and inside the Junction Box as a precaution against the effects of condensation.
4.3.2 Item 2 - Connector Retention bracket
The Connector rention bracket is not shown in this photograph (Fig. 2), but it is visible in Fig
5. The bracket fits onto the Connector Plate using the middle two screws. This retention
bracket has a series of forms to apply pressure at the rear of each ‘D’ connector shell. As
the bracket is fixed into position, by tightening the two fixing screws, the ‘D’ connectors
become locked and fully mated.
4.3.3 Item 3 - Frame retention bolts
Two of the rention bolts can be seen on the left side, the lower bolt is identified on the
photograph (Fig. 2), and this has a special significance as the main earth point for the case.
The entire inner card frame is removable from the outer casing. The two M6 hexagonal bolt
heads at each side secure the frame within the case. These bolts must not be removed
unless following the procedure described in section 5.4
