Black Box LEH1104A-2SFP Manuale Utente
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Page 18
Chapter 3: Installation
3.2.3 Alarms for Power Failure
There are two pins on the terminal block used for power failure detection. It provides the normally closed output when the power
source is active. Use this as a dry contact application to send a signal for power failure detection.
source is active. Use this as a dry contact application to send a signal for power failure detection.
Table 3-1a. Power failure alarms for LEH900 Series.
Power Input Assignment
Power 3
Power 3
12 VDC
DC jack
Power 2
+
12–48 VDC
-
Power ground
Power 1
+
12–48 VDC
-
Power ground
Earth ground
Relay output rating
1 A @ 24 VDC
Relay Alarm Assignment
Fault
Fault
Warning signal disable for the following:
• The relay contact closes if Power 1 and Power 2 both fail, but Power 3 is ON.
• The relay contact closes if Power 3 fails, but Power 1 and Power 2 are ON.
• The relay contact closes if Power 1 and Power 2 both fail, but Power 3 is ON.
• The relay contact closes if Power 3 fails, but Power 1 and Power 2 are ON.
Table 3-1b. Power failure alarms for LEH1000 and LEH1100 Series.
Power Input Assignment
Power 3
Power 3
47 to 57 VDC
DC jack
Power 2
+
47–57 VDC
-
Power ground
Power 1
+
47–57 VDC
-
Power ground
Earth ground
Relay output rating
1 A @ 250 VAC
Relay Alarm Assignment
Fault
Fault
Warning signal disable for the following:
• The relay contact closes if Power 1 and Power 2 both fail, but Power 3 is ON.
• The relay contact closes if Power 3 fails, but Power 1 and Power 2 are ON.
• The relay contact closes if Power 1 and Power 2 both fail, but Power 3 is ON.
• The relay contact closes if Power 3 fails, but Power 1 and Power 2 are ON.
NOTE: The relay output is normally in the open position when there is no power to the switch. Please do not connect
any power source to this terminal to prevent shorting your power supply.