Crystal 24VDC Loop Power Supply User Manual
24VDC Loop
Power Supply
Operation Manual
INTRODUCTION
The 24VDC Loop Power Supply (24VDCPS) is a portable, battery-powered, loop power supply and is ideal for sites where power is unavailable. The low noise
regulated output is suitable for use with smart transmitters. Power is automatically turned o when load is removed, preserving battery life. Outputs feature
—
short circuit protection. Three LEDs indicate power, low battery, and fault status. A protective boot and two AA batteries are included.
QUICKSTART/OPERATION DIAGRAM
24VDC Loop Power Supply Operation Manual 1
—
24 VDC output. Observe correct polarity.
Press to turn power on when connected to loop.
Must be connected to a load for On Key to function.
Output Terminals:
On Key:
LED signals:
On when loop is powered.
On when batteries are nearing depletion.
To avoid damage to rechargeable batteries, remove
when this LED is illuminated. Refer to the Approximate
Battery Life table on page 2 for battery life estimations.
On when unable to maintain 24V output.
A depleted battery, short circuit, or low loop impedance will
cause this LED to illuminate.
Auto-O & Power Hold Function
When the loop is connected, press the On key to enable the output voltage. The 24VDCPS does not have an O switch. When testing is complete, simply
disconnect the loop and the unit will turn o automatically. If the loop is re-connected within approximately 30 seconds, the unit will power on automatically.
BATTERIES
The 24VDCPS uses 2 AA batteries. Recommended batteries are Lithium (non-rechargeable), Alkaline, or NiMH (rechargeable). To avoid damage by over-dis-
charging, rechargeable batteries should be removed when the Low Battery LED
—
the Red Fault LED
cold weather operations.
Typical Battery Life (Conditions: 12 mA loop current, 23° C)
() illuminates, at which time the output voltage will have fallen below 24 V. Lithium batteries are recommended for best performance in
() illuminates. Non-Rechargeable batteries may continue to be used until
24VDC Loop Power Supply Operation Manual 2
Battery Chemistry Type Examples Typical Battery Life (hours)
Lithium Non-Rechargeable Energizer Ultimate
Rayovac Max Plus 815
Alkaline Non-Rechargeable
NiMH Rechargeable Energizer Recharge 9 Remove batteries immediately
NiMH (Low Self Discharge) Rechargeable Sanyo Eneloop 7.5 Remove batteries immediately
CAUTION: Do not use AA sized, 3.6 V Li-Ion batteries in the 24VDCPS. Doing so will damage the device.
!
Battery Replacement
Remove the protective boot and slide the battery cover o. Replace the batteries, taking care to note the correct polarity.
For best results, always replace batteries in pairs. Do not mix fresh and old batteries or batteries of dierent types.
CAUTION: To avoid damage by over-discharging, rechargeable batteries should be removed immediately when the Low Battery LED () illuminates.
!
Duracell MN1500
Energizer E91, EN91
14.5
(10 hrs at -20° C)
6
Low Battery Indication
2 minutes remaining at 24 V output
5 minutes until output drops below 18 V
30 minutes remaining at 24 V output
40 minutes until output drops below 18 V
()
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