7.46
SEL-351A Relay Instruction Manual Date Code 20080213
Inputs, Outputs, Timers, and Other Control Logic
Rotating Default Display (Only on Models With LCD)
For example, with the factory default settings for 51PP and CTR, setting
DP1_0 =::51PP will display 720.00 A pri.
The relay calculates the value to display by multiplying the 51PP setting
(6.00 A secondary) by the CTR setting (120), arriving at 720.00 A primary.
The relay displays the display point DP1_0 because the factory default
SEL
OGIC control equation DP1 = 0 (logical 0).
The calculations for the remaining time-overcurrent elements are similar,
except for 51NP which is multiplied by the CTRN setting.
If the display point setting does not match the correct format, the relay will
display the setting text string as it was actually entered, without substituting
the time-overcurrent element setting value.
Table 7.10 lists all the available Time-Overcurrent Elements that rotate on the
default display, subject to the number of available display points.
Displaying Time-Overcurrent Elements Example
This example demonstrates use of the rotating display to show time-
overcurrent elements in primary units. This example will set the 51PP and
51NP to display in the rotating default display.
Set the following:
Setting DPn = 0 and using the DPn_0 in the text settings allows the setting to
permanently rotate in the display. The DPn logic equation can be set to control
the text display—turning it on and off under certain conditions. With the relay
set as shown above, the LCD will show the following:
then,
With the control string set on the even display points
DP2, DP4, DP6, … and
the description set on the odd display points
DP1, DP3, …, each screen the
relay scrolls through will have a description with the value below it.
SET SET T SET L
CTR = 100 DP1_0 = PHASE TRIPS AT DP1 = 0
CTRN = 100 DP2_0 = ::51PP DP2 = 0
E51P = 1 DP3_0 = NEUTRAL TRIPS AT DP3 = 0
E51N = Y DP4_0 = ::51NP DP4 = 0
51PP = 5
51NP = 1
PHASE TRIPS AT
500.00 A pri
NEUTRAL TRIPS AT
100.00 A pri
Courtesy of NationalSwitchgear.com
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