Chapter 4
Using Trending to Aid Troubleshooting
General
The Trend function of the Bulletin 1395 allows the user to sample data in
real time and store that data for examination or output. The Trend function
can sample any source configuration parameter value in the 1395, at
programmable sample rates, and output that data to the user through the
Bulletin 1300 programming terminal or any of the adapter cards. This
function can be very useful for capturing data that occurs in the Drive
during a fault or malfunction. Through the use of a programmable trigger,
data sampling can be triggered when a certain event occurs. Data before and
after the trigger event is captured and stored. This data can then be used to
examine the operating status during the trigger event.
Trend Programming
The Trend sample data consists of 100 consecutive data values that are
stored when the programmed trigger conditions are met. The parameter to
be sampled must be a configuration source that is linked to one of four trend
configuration sink parameters, Parameter 50 “Trend 1 Input” through
Parameter 53 “Trend 4 Input”. For example, if Parameter 106 “Velocity
Fdbk” is the desired data to be sampled by trend 1, Parameter 50 “Trend 1
Input” should be linked to Parameter 106 “Velocity Fdbk”. All four trends
can be active simultaneously, with no system degradation.
To define the trigger event information for each trend, set-up parameters are
programmed by the user. For the above example involving Trend 1,
parameters 910 to 917 must be programmed. The following paragraphs
reference Trend 1. Trends 2 through 4 are programmed in the same way,
using their associated parameters Trend 2 is programmed through
parameters 920 - 927, Trend 3 through 930 - 937, and Trend 4 through 940 -
947.
The trigger event, which causes data to be sampled, is programmed by
defining two operands and an operator. When the condition defined by the
operator exists between the two operands the trend is triggered and the
programmable data samples after the trigger are captured. The two operand
parameters are selected by Parameter 910 “TR1 Opnd Param X” and
Parameter 911 “TR1 Opnd Y” and can be programmed to all configuration
and set-up parameters. The operator is defined in Parameter 912 “TR1
Operator”, the selections consist of:
Greater Than <.GT> - Compares the signed value of the parameter
specified in Parameter 910 to Parameter 911. If the result of the comparison
is positive, the trigger will occur.
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