Document: LT0273 MX4428 MXP Engineering / Technical Manual
Device Information and Programming
Issue 1.5 24 March 2006 Page 3-47
3.23 LPS800 LOOP POWERED SOUNDER MODULE
3.23.1 GENERAL
The LPS800 Loop Powered Sounder Module is suitable for 24V DC outputs powered by the
MX Loop. It can supply up to 75mA at 24VDC.
When inactive, a reverse polarity supervision is applied to the load wiring. The load devices
must therefore have reverse blocking diodes.
The load supervision can detect short and open circuit states on the load wiring only when
the output is inactive.
The load must be isolated from ground and all voltage sources. All inductive loads (e.g. bells
or relays) must have back-emf diodes or other noise clamping devices fitted.
Recognition of a fault condition takes about 30 seconds.
3.23.2 LPS800 SPECIFICATIONS
Dimensions Height: 87mm Width: 148mm Depth: 14mm
Weight 100g
Line Connections L-, L+
Supply Voltage 20V – 40V
Supply Current Standby Current : 450uA (typical)
Operated with load up to 8mA : 12mA.
Operated with load over 8mA : Load current + 4mA
Output Circuit ELD 22k ohms, 0.5 watt
Output Current Rating 75mA@24V nominal.
Voltage Drop 2V max
Note that the LPS800 has a minimum voltage drop of 2V between the line voltage and the
output terminals. When the loop voltage is less than 26V, the output voltage may be less
than 24V. At the minimum loop voltage of 20V, only 18V will be available for the sounder
devices. From this you must subtract the voltage drop in the wiring to the sounder devices to
obtain the voltage at the sounder device terminals. You must ensure the sounder devices
operate correctly at this voltage.
Alternatively you must design the loop so that the minimum voltage is higher than 20V and
sufficient to give the required voltage at the sounder terminals. Refer to section
3.2.2 for loop
voltage drop calculations.
The load must be isolated from ground and all supplies.
3.23.3 MX4428 PROGRAMMING OPTIONS - LPS800
The LPS800 is programmed as an SNM800. Refer to section 3.22.4.
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