3M Static Monitor 790, Руководство пользователя

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4
1.0 Theory of Operation
The 3M
™
Static Monitor 790 is designed to continuously monitor the voltage
level on an operator(s) using a high impedance voltage measurement circuit.
The measured operator’s voltage is compared to one of four user selectable
(1V, 3V, 6V and 9V) internal reference voltages. An alarm will sound with a
corresponding red flashing lamp(s), when an operator’s voltage level (caused by
static generation) exceeds the selected internal reference voltage.* In addition,
a wrist band contact detection circuit is also employed to let the user know if
the wrist band is being worn improperly or has experienced a loss of continuity
between the ground cord and wrist band.
The ground connection of the Static Monitor 790 is continuously monitored
through a low DC current-loop measurement circuit. The ground connection of
an equipment chassis can also be monitored when connected in series with the
monitor’s ground measurement circuit. An alarm will sound with corresponding
red lamps, when this loop resistance exceeds 10
Ω
.**
If all monitored components are operating within the selected operating
parameters of the Static Monitor 790, a green lamp will illuminate.
The Static Monitor 790 uses a modified version of the 3M
™
Dual Conductor
Wrist Band (VM Series) and the standard 3M
™
Dual Conductor Grounding Cord
(see Accessories Section).
*Voltage alarm levels ±15%
**Ground disconnect ±20%
***Ordered separately
AC Adapter
Mounting Plate
3M
™
Static Monitor 790
Chassis/Ground
Cords with Two-
Wire Connector
Figure 1 - 3M
™
Static Monitor 790