User Guide: Technical Reference
SECTION 3 OPERATING THE
ioLink 4
PRELIMINARY
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-3-10
3.1.3.5 ADVANCED Menu Item Descriptions
The Advanced Menu has advanced options that are intended to allow knowledgeable users and
technicians to debug problems. In general, most users will not need to use these features.
Table 3-6. Advanced Menu Options
BER Threshold
This threshold is used to monitor the Pre-FEC BER of the link.
If this threshold is exceeded for the specified BER Interval (see
below), the FEC BER alarm is given in the ALARM menu. The
BER Threshold defaults to 2.0 E-7.
BER Interval
This is the interval of time, in seconds, that the BER Threshold
must be exceeded to cause the FEC BER alarm to appear in
the ALARM menu. Once the Pre-FEC BER exceeds the BER
Threshold, the
ioLink
begins timing. If the Pre-FEC BER falls
back below the BER Threshold, the timer is reset to zero.
Otherwise the timer continues until the specified interval is
surpassed, which then causes the FEC BER alarm to register
in the ALARM menu. The BER Interval defaults to 100
seconds.
Jitter Atten
Jitter attenuation is provided by an elastic store in the LIU.
When enabled, data bits are clocked into the elastic store
using the line clock and then clocked out using the de-jittered
clock from the jitter attenuation loop. Insertion of jitter
attenuation produces a delay of 16 bits.
Acquire Thresh
This is a threshold parameter that affects the initial
synchronization process of the link. Typical values are from
30
H
to 60
H
(
H
= hexidecimal).
Tracking Thresh
This is a threshold parameter that affects the continuing
synchronization process of the link. Typical values are from
0A
H
to 12
H
(
H
= hex).
FEC BER
This menu item allows the user to turn the error rate testing on
or off.
