If you know anti satic wrist straps you can skip the following brief explanation: In case you are unfamiliar with these accessories, the use is simple, the wrist strap has a wire with a banana connector which is connected to the wrist strap conductive plate. When working with components sensible to ESD, the person that wears the wrist strap must plug the banana connector in the ground connector, the last has a wire that is wired to the outlet ground.
The only solution I got, is to get a dual wire wrist strap (as shown in the picture bellow) which has two plates wired separately in a single aux cable. In this way I can measure body resistance between both plates.
Actually, not true! That would be potentially life threatening if the hand contacted a live higher voltage circuit. There is a 10meg or so resistor in series with the ground strap which works perfectly for draining static charges.
Yeah, you measure the resistance between your body and ground. But it's high resistance, somewhere between 10M & 100M Ohms so a regular ohmmeter may not do it. (It's high resistance so you don't get killed by touching high voltage.)
Your work surface is also supposed to be grounded so a charge doesn't build-up on it.
It's probably OK unless it's very old and something is broken...
I've never seen "dual" wrist strap.
Where I work we have a special tester, but it's expensive & tied into the network and we type-in out employee number so they know everybody is testing everyday. We also have foot straps (or I have anti-static shoes) and it tests those at the same time.
The resistance between ground and the point of connection is close to zero. A wise person would not include the resistor in the measurement, but another person might include the resistor, and expect to encounter ~10Meg.
Do you mean a wrist strap for each wrist? They are used where even a volt or two may disturb a test and you can get that momentarily by body part movements.
My body read is something between 0.9M and 1M Ohms with a Fluke 117 multi meter.
I got DESCO 19860 dual wire wrist strap, it has two plates, each plate connected to one of the two conductors from a aux cable.
I need something that can monitor that the person who is working at the workstation is grounded, and activate an alarm (a buzzer or a red light) if not during the whole shift.
I have some proposals that are between $100 and 300$ usd, but since it has to be replicate on 50 workstations, the price rises a lot. So I have been asked to build some gizmo to solve the problem.
I bought a bunch of used electronic work stations years ago. I think one had some kind of indicator for what you are thinking about. Look for the complete line is DESCO stuff and see if they have one.
