3M 725 Instructions Manual - Page 6

Browse online or download pdf Instructions Manual for Measuring Instruments 3M 725. 3M 725 15 pages. Wrist strap monitor
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Caution

The Model 725 Monitor does not have

the capability of verifying that the

ground point is a suitable ground. If

you are not sure what a suitable ground

is, contact a licensed electrician before

installation.

The Model 725 Monitor requires only

a small amount of current to operate.

When the red lamp and the audible

alarm are activated simultaneously the

monitor requires approximately 5 µA

of current. When the lamp and alarm

are not activated (normal condition)

the monitor requires approximately

µA of current.

As with any battery operated electronic

device, the life of the battery will be

determined by the frequency of use.

However, for the Model 725 Monitor

you can expect a battery life of

approximately one year in continuous

operation under normal conditions.

Voltage on Operator When Connected to the Model 725 Monitor

No Skin Resistance

200K Ohm Skin Resistance

Likely Case Before Alarm

Worst Case Before Alarm

Absolute Worst Case

Condition

Note:

Use an alkaline battery for longer life.

The Model 725 monitors the battery

voltage and alerts the operator when it

is necessary to change the battery.

When the battery voltage falls below

6 volts the red lamp will illuminate

with no audible alarm. At this time the

Model 725 is still operational, making

reliable resistance measurements

of the wrist strap assembly and the

ground connection.

Voltage on Operator when Connected

to the Model 725 Monitor

There is a concern about the voltage

that is applied to an operator while

they are connected to a monitor.

Some of today's electronic

components are extremely sensitive

to electrostatic discharge from a person

(less than 10 volts). The following

chart for the Model 725 Monitor

illustrates the level of voltage that will

appear on the operator under various

resistance conditions.

Observed Voltage

0.8V

0.9V

3.5V

6.8V

9.0V