Date Code 20050615
Instruction Manual
SEL-3022 Transceiver
Introduction & Specifications
Connections, Reset Button, and LED Indications
1.7
Cryptographic Manual—Do Not Copy
IMPORTANT:
Do NOT wire power to both the compression
terminals and the 2.5 mm jack. Use only one power
connection at a time.
Alarm Output Connection
Use the solid-state alarm contact to alert you to problems either with the
communications channel or the SEL-3022. See
Section 5: Testing and Troubleshooting
for more details. To maintain the UL rating of the SEL-3022, connect the alarm output
contact as follows:
1.
Use an external load to limit current to less than 100 mA through the
alarm contact. There is no means within the SEL-3022 to limit
current through the alarm contact. You must ensure that the external
circuit connected to the SEL-3022 limits the current. For example, a
typical SEL contact input draws 4 mA.
shows a typical
connection of a wetting source (125 Vdc), the SEL-3022 solid-state
output, an SEL-2030 contact input, and an optional load resistor. In
this case, because the contact input impedance limits the current to
less than 100 mA, the load resistor is not necessary. If the sensing
input does not have a means of limiting the current to less than 100
mA, then you must use a high wattage resistor. Select a load resistor
with the proper wattage rating to limit the current. For example,
assume the wetting source is 125 Vdc and that the sensing input
requires 10 mA to assert. You can use the following calculation to
determine the load resistor: 125 Vdc/ 10 mA = 12.5 k
Ω
. Calculate the
minimum wattage: (10 mA)
2
• 12.5 k
Ω
= 1.25 W. You would
typically double this parameter to 2.5 W to ensure proper operation
over temperature and life. You should verify proper derating with the
resistor data sheet.
2.
Circuit protection should include an in-line fuse rated for 0.5 A or
less with a voltage rating greater than the voltage you intend to use.
shows a typical alarm output installation.
CAUTION:
Current through the alarm output must be limited to less
than 100 mA.
!
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Summary of Contents for SEL-3022
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