C
ONVERTER
RS-232, RS-422, RS-485
O
PERATION
M
ANUAL
IOA55-1c
August
2009
13
Signal wire should be connected with a wire, of which the impedance of twisted wire pairs is
120
Ω
. The maximum wire length to meet the requirements is
1200 m.
However, it is not
advisable to use such long connections. The length of a twisted wire should be limited in
favour of the length of an optic-fibre wire.
2.2. Signalling
Depending on its version, the device is equipped with either 2 or 3 signalling parts.
Their arrangement on the front panel is shown in figure 10.
TR-55
6-60V DC
Figure 10. The TR-55 converter signaling parts
The signaling parts have the following meaning:
PWR (green diode)
– signals that the power supply works properly.
LOOS (red LED)
- Loss of Optical Signal . It means:
- damaged optical transmission in every way independently
- pollution one of both fibre optics connectors
- damaged fibre optic
- one of both devices is swiched off,
- fibre optic is disconnected on other side device
PWR
LOOS along the
optical path 1
LOOS along the
optical path 2
