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I.L. 40-201.9
System
Voltage
8.5 Vdc
+12 Vdc
1.8
Analog Input Module
This module (
mounted on the Backplane module. These transformers provide the following ac values: V
V
, V
B
C
with a cut-off frequency determined by the Nyquist criterion and the system sampling rate. Val-
ues I
, I
A
All 7 inputs (V
The A/D converter is a self-calibrating 12-bit (plus sign), with an internal track-and-hold ampli-
fier. Additionally, the autoranging circuitry provides 16 bits of dynamic range needed to mea-
sure high fault current values.
1.9
Contact Outputs
• 4 make contacts (2 trip, 2 BFI); 8 additional optional contacts when Extended Contact Output
option is used
• Reclose initiate (2 Form A)
• Reclose initiate (2 Form A)
• Reclose block (2 Form A)
• General start (1 Form A)
• System failure alarm (1 Form B)
• Trip alarm (2 Form A)
• Channel alarm (1 Form A)
2.
SELF-CHECKING SOFTWARE
REL 352 continually monitors its ac input subsystems using multiple A/D converter calibration-
check inputs, plus loss-of-potential and loss-of-current monitoring. Failures of the converter, or
any problem in a single ac channel which unbalances nonfault inputs, trigger alarms. Self-
checking software includes the following functions:
a. Digital Front-end A/D Converter Check
b. Program Memory Check Sum
Immediately upon power-up, the relay does a complete ROM (EPROM) checksum of program
memory. Afterwards, the REL 352 relay continually computes the program memory checksum.
1-4
Circuitry Supplied
Processor Board
+5 Vdc Supply
Analog Circuitry
See Appendix G for further details
) interfaces with the voltage and current transformers that are
see Appendix H
, I
, I
, I
. These values are applied to active third-order Butterworth antialiasing filters,
A
B
C
, I
are summed to produce 3I
B
C
, V
, V
, I
, I
, I
A
B
C
A
B
C
Power Automation and Protection Division
System
Circuitry Supplied
Voltage
-12 Vdc
Analog circuitry
Channel Modem,
+24 Vdc
PONI Module
.
0
, 3I
) are connected to the multiplexer and to the A/D converter.
0
System
Circuitry Supplied
Voltage
Channel Modem
-24 Vdc
VF Display COPS
Chips
Vacuum Fluorescent
6.5 Vac
Display Filament
REL 352 Version 1.00
,
A
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