7
3M Dual Conductor
Remote Input Jack
Model 733
Figure 1 – 3M Workstation Monitor Model 724 with remote input jacks.
3M Dual Conductor
Remote Input Jack
Model 732
3M Workstation
Monitor Model 724
SECTION 1
Theory of Operation
The 3M Workstation Monitor Model 724 (Figure 1) is designed to monitor the
operation of the wrist strap grounding systems of two operators. To accomplish
this, it uses a DC current source to measure a loop electrical resistance. The
system uses a special wrist band and ground cord that contain two independent
elements. The Workstation Monitor Model 724 employs two selectable test
voltages (9 and 16 volts) and resistance limits (10 Megohms and 35 Megohms).
It also monitors the grounding of up to two 3M work surfaces. The Workstation
Monitor Model 724 contains a current-limiting resistor, through one side of the
wrist band, through the skin of the wearer under the band, through the second
side of the wrist band, through the second conductor of the ground cord that
contains a current-limiting resistor, and finally back to the monitor.
Selection of Test Voltage and Resistance Limit