Schweitzer Engineering Laboratories SEL-749M - I;O Configuration; Table 4.27 Load Control Settings; Table 4.28 Analog Output Setting

4.31
Date Code 20080918 Instruction Manual SEL-749M Relay
Protection and Logic Functions
I/O Configuration
Load Control Function
NOTE: In addition to setting the load
control levels, you must assign
LOADUP and LOADLOW to auxiliary
output relays (one each); see
Tab le 4. 37 , and Figure 2.6 for
connection diagrams.
The SEL-749M provides an ability to control external devices based on the
parameter load control selection. You can select current, power, or thermal
capacity utilized to operate auxiliary outputs. Load control is active only when
the motor is in the running state. It is disabled when relay word bit 50S asserts
(current exceeds 2.5 pu).
When the selected parameter exceeds the load control upper setting level for
1 second, the auxiliary relay assigned to LOADUP will operate. The auxiliary
relay will reset when the parameter drops below the upper level setting for
1 second.
When the selected parameter drops below the load control lower setting level
for 1 second, the auxiliary relay assigned to LOADLOW will operate. The
auxiliary relay will reset when the parameter is above the lower-level setting
for 1 second.
You can use this feature to control the motor load within set limits.
I/O Configuration
Analog Output
The SEL-749M provides a 4–20 mA dc analog current output with a variety of
output parameters. Use the analog output select setting (AOPARM) to select
the desired parameter from the list of available options. Table 4.29 shows
description and scaling of the output for different parameter selections.
Table 4.27 Load Control Settings
Setting Prompt Setting Range
Setting Name :=
Factory Default
LOAD CONTROL SEL Off, Current, Power, TCU LOAD := OFF
LD CTL CUR UPPER Off, 0.20–2.00 xFLA LOADUPP := OFF
LD CTL CUR LOWER Off, 0.20–2.00 xFLA LOADLOWP := OFF
LD CTL PWR UPPER Off, 1–25000 kW LOADUPP := OFF
LD CTL PWR LOWER Off, 1–25000 kW LOADLOWP := OFF
LD CTL TCU UPPER Off, 1–99 %TCU LOADUPP := OFF
LD CTL TCU LOWER Off, 1–99 %TCU LOADLOWP := OFF
NOTE: Prompt of the settings
LOADUPP and LOADLOWP are
dependent on the LOAD setting. All
possible prompts are shown in
Tab le 4. 27 . The relay will show only
the appropriate prompts based on the
LOAD setting.
Table 4.28 Analog Output Setting
Setting Prompt Setting Range Setting Name := Factory Default
ANALOG OUT SEL LOAD_I, AVG_I,
MAX_I, %THERM,
WDG_RTD,
BRG_RTD, PWR_kW,
PF
AOPARM := LOAD_I
Courtesy of NationalSwitchgear.com