14 Installation Instructions
Publication 1746-IN004B-EN-P - March 2008
Power Supply Undervoltage Operation
SLC 500 controllers continue to operate (hold-up) for a short period of time if the
input voltage to the power supply drops below the recommended operating
voltage range. The controller continues to scan the user program and control I/O
during this time. CPU hold-up for each power supply is shown on pages 14 and 16.
SLC 500 controllers turn OFF (stop scanning and disable outputs) if input voltage to
the power supply is removed or drops below the recommended operating range
for a period exceeding the CPU hold-up time. The controller resumes operation
automatically when the input voltage is restored to normal.
If the input voltage to the 1746-P7 power supply falls into a range of 4 to 9V for a
period exceeding the CPU hold-up time, the controller turns OFF and will not turn
back ON until input voltage is increased to 11V dc.
General Specifications (1746-P1, 1746-P2, 1746-P3, and 1746-P4)
Attribute Value
1746-P1 1746-P2 1746-P3 1746-P4
Line voltage 85...132/170...265V ac
47...63 Hz
19.2...28.8V dc 85...132/
170...250V ac 47...63
Hz
Typical line power
requirement
135VA 180VA 90VA 150VA
Inrush current, max 20 A 45 A
Internal current
capacity
2 A at 5V dc
0.46 A at 24V dc
5 A at 5V dc
0.96 A at 24V dc
3.6 A at 5V dc
0.87 A at 24V dc
10.0 A at 5V dc
2.88 A at 24V dc
(1)
Fuse protection
(2)
1746-F1 or
equivalent
(3)
(4)
1746-F2 or
equivalent
(3)
(5)
1746-F3 or
equivalent
(3)
(6)
Fuse is soldered in
place.
24V dc user-power
current capacity
200 mA Not applicable
1 A
(1)
24V dc user-power
voltage range
18...30V dc 20.4...27.6V dc
User-supplied
overcurrent
protection
(7)
, max
15 A Not applicable 15 A
Temperature,
ambient operating
0...60 °C (32...140 °F)
Current capacity is derated 5% above 55 °C (131 °F).
0...60 °C
(32...140 °F)
no derating
Isolation
(8)
1800V ac RMS for 1 s 600V ac RMS for 1 s
(version B or later)
2600V dc for 1 s
CPU hold-up time
(9)
20 ms (full load) 3000 ms (no load) 5 ms (full load)
1000 ms (no load)
20 ms (full load)
3000 ms (no load)
