Johnson Controls MS-FIT100-0 User Manual page 40

Table 9: FIT Display Table
Menu Fit Display Short Meaning
Monitor LoopTime
Monitor PcktErrs
Monitor CharErrs
Monitor Baudrate
Monitor Chrs/Sec
Monitor Over Run
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Expert
Mode
Loop Time X
Packet Errors X
Character Errors X
Communication X
Baud Rate
Characters per X
Second
Over Run of X
Data
Description
Indicates how much time passes between
the periods when the device allows initiation
of messages on the network. This time is a
strong indicator of network performance and
is associated strongly with the amount of
traffic or errors on the network. Shorter times
indicate a more responsive network. Longer
times indicate an increasingly busy and slow
network.
Counts errors detected in the data portion
of data frames sent to the device. Many data
frames are used only for protocol control
and do not contain a data portion, and thus
cannot have Data CRC Errors. The Header
CRC Errors check must be successful before
the device attempts a Data CRC check. This
attribute supplies an error count for the Bus
Health Index attribute.
Some possible reasons are bus exposure to
noise or poor wiring.
Counts the number of errors detected in
the individual data bytes received by the
device. A framing error occurs when the
device receives a stop bit in the wrong state.
This attribute supplies an error count for the
Bus Health Index attribute. Framing errors
are usually caused by electrical noise on the
bus, message collisions, incorrect baud rate
settings, bus wiring or termination errors,
or devices that are not operating within the
BACnet specified timing. Framing errors
generally cause CRC errors since the frame
has been corrupted.
The speed at which controllers are
communicating. MS/TP is normally 38,400 bits
per second (bps).
The number of characters in the frames
currently being transmitted per second.
Displays the number of times the MS/TP port
hardware loses received data because the
device is too slow in reading the data. An
overrun error occurs when the hardware
receives a byte before it moves the prior byte
to a buffer.
MS-FIT100-0 Field Inspection Tool User Guide