JVA ZLM1 & ZLM4 Low Voltage Monitors

The JVA ZLM1 is a single zone low voltage electric fence monitor. The ZLM1 may be used by itself or in conjunction with a number of high voltage security electric fence energizers.

The ZLM1 monitors a single loop of fence wire reaching out up to several hundred meters long, to detect someone tampering with the fence by cutting or shorting the wires using intrinsically safe, isolated Extra-Low Voltage (ELV) DC.

The ZLM1 will generate an alarm when one of the low voltage wires:
• Is cut (Open Circuit)
• Shorted to ground
• Shorted to a high voltage fence wire
• Cross-coupled to another low voltage wire 

The ZLM4 is a 4-zone, low voltage,electric fence monitor. The ZLM4 maybe used by itself or in conjunction witha number of high voltage securityelectric fence energizers. The ZLM4monitors up to 4 loops of fence wire,each up to several hundred meterslong, to detect someone tamperingwith the fence by cutting or shortingthe wires.When used in conjunction with a highvoltage electric fence energizer, theZLM4 is wired to the non-energizedearth wires on the fence. In this way,the ZML4 can be used to split one highvoltage zone into up to 4 low voltagemonitored zones for improvedtargeting of the response to potentialsecurity breaches.

The ZLM4 is compatible with the JVA Z series energizers. It may be connected via a keypad bus network with other Z-series devices to enablethe whole group to be controlled via one keypad, or linked to a PC running JVA Perimeter Patrol software. The ZLM4 monitors a low voltageloop using intrinsically safe, isolated ELV DC. It employs a continuity check for detecting open circuits, DC voltage level sensing to detect ashort to ground and pulse voltage sensing to detect a short to a line powered by a high voltage fence energizer.

The advanced features of this device allow the performance to be tuned to the fence and to the particular requirements of the site. This is doneby adjusting the device’s programmable options. The ZLM4 will report an alarm on: detecting a low voltage loop cut (open circuit); shorted toground (short); when high voltage from an electric fence energizer wire is shorted to the monitored low voltage loop; or when two low voltageloops short to one another (cross couple).