User guide

P/N: 021-00154, Rev. A.6 - updated for V4.7 Tools Page | 96
Trend logging, Event logging or Fault logging. Memory
Allocation sets the size of the particular bucket (in kilobytes)
out of a maximum of 5megabytes. The Data Protected
checkbox determines if new data can be written over old
data. The Time Stamp checkbox gives the option of
recording time, date and day in the log. Alarm and Alarm
Percent work together as a means of showing when the
Allocation Block is getting close to being filled. Scan Rate
determines how often the variables within a Trend log will
be tracked. The Number of Variables shows how many
variables will be tracked. Variable Names identify the
variables to be tracked and Scaling Factors allow for
floating point variables.
A common question is how many events can be recorded in
the DVC70 memory and for how long. Each message
consists of an optional timestamp that is 7 bytes long plus 2
bytes per variable defined for the event. When in trend
mode the scan rate also applies. So for the maximum of 10
variables in trend mode with a timestamp per line the data length is 27 bytes. Thus 4992k/27 = 185k events. At
one event per second this would equal 185Ksec/3600 sec per hour = 51 hours of recording. Another way of
looking at it is how many recordings can be captured. The range is 9 (1 variable and the timestamp) to 27 (10
variables and the timestamp) bytes per recording or 555k to 185k recordings. In event mode the time to record
185K to 555K events will vary depending how often you trigger the recording in your application.
Name:
The name used in the bubble logic screen to access this variable and properties.
Range: 16 Alpha/Numeric characters only with no spaces.
Description:
Used for output log description only.
Range: 40 Alpha/Numeric characters.
Data Type:
Identifies the data logging type (Trend or Event/Fault)
Range: Trend, Event, or Fault.
Note: Event and Fault logs are the same type of log. The nomenclature Event and Fault was chosen in order to
make it easier for the user to perceive fault situations.
Memory Allocation:
Determines the size of the Memory bucket
Range: 0, 128K, 256K, 512K, 1024K, 1536K, 2048K, 2560K, 3072K, 3584K, 4096K, 4608K, and 4992K
Note: The maximum amount of memory that can be allocated by all five-allocation blocks combined is 5120K.
Data Protected:
When the allocation block is filled to 100%, Data Protected determines if the stored data can be overwritten or
not.
Range: On, Off.