CHAPTER 4: OPERATION
OPERATION
MULTILINK ML600 ETHERNET COMMUNICATIONS SWITCH – INSTRUCTION MANUAL
4–3
FIGURE 4–1: Alarm contact terminal block
The NC alarm contact is held closed when there is power on the main board inside of the
ML600. This provides a “hardware operated alarm” since the NC contacts will open when
internal power is lost, either from an external power down condition or by the failure of the
internal power supply.
Take note of the following aspects of the alarm contacts:
1.
The two-position terminal block is provided next to the DC power input, as
shown above.
2.
The alarm relay contact is hardware operated.
3.
By default, the alarm relay contact is NC (normally closed). It will open if there
is any loss of power to the electronics inside of the unit.
4.1.7
Power Budget Calculations with Fiber Media
Receiver sensitivity and transmitter power are the parameters necessary to compute the
power budget. To calculate the power budget of different fiber media installations using
MultiLink products, the following equations should be used:
(EQ 4.1)
where: OPB = optical power budget
P
T
= transmitter output power
P
R
= Receiver Sensitivity
The worst case OPB is as follows:
(EQ 4.2)
The worst-case distance is calculated as follows:
(EQ 4.3)
The cable loss in dB/km is defined in the following table:
OPB
P
t min
(
)
P
R min
(
)
–
=
OPB
worst
OPB 1dB (LED aging)
–
1dB (insertion loss)
–
=
distance
worst
worst-case OPB (in dB)
cable loss (in dB/km)
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