Bently Nevada 3300/01 Series, Operation Manual

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System Monitor
80175-01
16 PROTOCOL SPECIFICATIONS
MONITOR STATUS
The monitor status indicators have a value of 1 o r 0. Each monitor will have these three status
values associated with it: Alert, Danger and not OK. Individual channel status is not available.
If any channel of a monitor is in alert, then the monitor status is Alert.
The monitor status values will b e ordered Alert, Danger, n o t O K a n d occupy contiguous
protocol addresses starting at address 0. To read the monitor statuses use the Read Input
Status command (function code 2). A simple formula for computing the starting address for a
monitor's status values is
Starting address = 3(number of monitors to left of the selected monitor, including empty
slots)
When a monitor position is not filled with a monitor, then the status values for that position are
allocated but the values are invalid.
Example 1:
Retrieve the status values from a 3300 rack which contains a vibration monitor in
slot 2 and a 6-channel temperature monitor in slot 3.
The Read Input Status query message will specify 6 status points starting at point
address 3 . T h e modbus response message will p a c k t h e response d a t a into
individual bits in the response message. Each bit represents a status point. A one
bit in the response message indicates a true status. In the above example, if the
monitor in slot 2 is showing alert and not OK and the monitor in slot 3 is showing
danger, then the response message will consist of one data byte with a value of
15 hex (21 decimal). The response byte will be as shown below.
0 0 0 1 0 1 0 1
Slot 2 monitor Alert
Slot 2 monitor Danger
Slot 2 monitor not OK
Slot 3 monitor Alert
Slot 3 monitor Danger
Slot 3 monitor not OK
Remaining bits zero filled
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