The Desco model 19241 body voltage monitor is a single station continuous monitor for an operator ESD worksurface and tool ground. It's powered by a 120-240 volt AC adapter with a five volt DC output.
When you've got this plugged in, the monitor will go through an alarm sequence for each monitor circuit. Each circuit has a dedicated LED for operator, mat, tool, and for a supervisor.
The mat ground circuit is shown on the right. And the utility ground is shown on the left. We can demonstrate the mat ground monitor function by unsnapping the ground cord. The alarm will go off.
The tool monitor circuit is shown by an aluminum plate, representing a tool that should be grounded. There's a monitor circuit and a ground circuit. A disconnect of the tool ground will result in an alarm from the monitor.
The operator and supervisor circuits work with a dual-wire wrist strap, such as the Desco MagSnap 360. Both circuits monitor for the path-to-ground and voltage on the body in excess of plus or minus three volts. The path-to-ground alarm can be demonstrated by removing the coil cord from the wristband.
We can demonstrate the voltage on the operator in excess of plus or minus three volts by using a nine volt battery. While touching one lead with a finger, touch the other lead to a known ground. The induced voltage will cause the monitor to alarm.
The monitor comes with a mounting bracket that can be used for mounting under the bench or another convenient location.