Rockwell Automation 1395 Digital DC Drive FRN 5-10.10/9.30 - Manual (Page 108)

Chapter 5
Functional Description
5-22
5. AND (.AND.) – Compares the bits(s) of a 16 bit value for the
parameter specified by Operand X to the bit(s) for the parameter
specified by Operand Y. If ALL of the same bit(s) are set to “1”
in both parameters, the trend is triggered Generally Operand Y is
set up to use one of the Bit Trend Constant parameters
(Parameters 904 through 907).
6. Negated AND (.NAND.) – Compares the bits(s) of a 16 bit value
for the parameter specified by Operand X to the bit(s) for the
parameter specified by Operand Y. If ALL of the same bit(s) are
set to “0” in both parameters, the trend is triggered Generally
Operand Y is set up to use one of the Bit Trend Constant
parameters (Parameters 904 through 907).
7. Or (.OR.) – Compares the bits(s) of a 16 bit value
for the parameter specified by Operand X to the bit(s) for the
parameter specified by Operand Y. If ANY of the same bit(s) are
set to “1” in both parameters, the trend is triggered Generally
Operand Y is set up to use one of the Bit Trend Constant
parameters (Parameters 904 through 907).
8. Negated OR (.OR.) – Compares the bits(s) of a 16 bit value
for the parameter specified by Operand X to the bit(s) for the
parameter specified by Operand Y. If ANY of the same bit(s) are
set to “0” in both parameters, the trend is triggered Generally
Operand Y is set up to use one of the Bit Trend Constant
parameters (Parameters 904 through 907).
Adjusting the Data Sample Rate – The sample rate for data acquisition
has a programmable range of 4ms through 30 seconds (In 4ms increments).
The rate at which the data is sample and at which the trigger condition is
evaluated is the same up to 40ms. This assures that possible trigger
conditions will be monitored whenever the sample rate exceeds 40 ms.
The sample rate can be changed while a trend is active.
Setting the Number of Post Samples – The number of data samples
taken once a trigger condition has occurred is programmable. The range is
0 through 99, with one sample reserved for the instance the trigger
condition becomes true.
Typically, when a trend buffer is set to trigger on a fault, the post sample
parameter would be set to a lower number. 20 samples is a good number.
This allows you to evaluate data before the trigger event on the trended
parameters.
When a trend buffer is set up as a level detector, the post sample parameter
is generally set to a higher value. 80 samples is a good number. This
allows you to evaluate what happened after the trigger occurred.