8
The memory's capacity is 685,000 values; beyond this the oldest values are
overwritten (ring memory, FIFO)�
The history can be configured, read and reset via the PC software�
5.3 Real-time clock
The unit has an integrated real-time clock including a buffer battery for the time
stamp in the history memory� The time is synchronised with the system clock when
the history is reset via the PC software�
6 Functions
The basic functions of the unit are set via the PC software�
Only parameters for alarming and scaling of the signals can be set via the buttons
on the unit → 8.1 Programming via pushbuttons
6.1 Monitoring function
The VNB211 can monitor up to two internal characteristic vibration values� The
characteristic values are activated and configured via the PC software� Monitoring
can be effected in acceleration or vibration velocity in a frequency range that can
be set�
On delivery, the first characteristic value monitors the effective value of the
vibration velocity to ISO 10816 in the frequency range of 10���1000 Hz�
On delivery, the second characteristic value monitors the maximum peak of the
acceleration in the frequency range of 10���6000 Hz�
6.2 Input function
Monitoring can be extended by another vibration measuring point or a process
value via the external input of the VNB211�
For the external input it is also possible to monitor up to two characteristic
values� With an extension by a vibration measurement point (with a VNA001
acceler Y cable) the same parameters can be configured as with internal
characteristic vibration values�With an extension by a process value (via an
analogue 4���20 mA current signal) the process value (e�g� a storage temperature
or pressure) can be monitored for exceeding and/or falling below the limit value�
On delivery, the first characteristic value for the external input is configured as
temperature monitoring (e�g� connection of a TT3237)�
The second characteristic value is deactivated on delivery�
