What is noise
Electromagnetic interference (EMI), also called radio-frequency interference (RFI) when in the radio frequency spectrum, is a disturbance generated by an external source that affects an electrical circuit by electromagnetic induction, electrostatic coupling, or conduction.The disturbance may degrade the performance of the circuit or even stop it from functioning. In the case of a data path, these effects can range from an increase in error rate to a total loss of the data.
Both man-made and natural sources generate changing electrical currents and voltages that can cause EMI: ignition systems, cellular network of mobile phones, lightning, solar flares, and auroras (northern/southern lights). EMI frequently affects AM radios. It can also affect mobile phones, FM radios, and televisions, as well as observations for radio astronomy and atmospheric science.
Electromagnetic interference can be categorized as follows:
Narrowband EMI or RFI, which typically emanates from intended transmissions such as radio and TV stations or mobile phones.Broadband EMI or RFI, which is unintentional radiation from sources such as electric power transmission lines.
Types of noise
Noise is what we refer to as electro magnetic interference ( EMI). This interferes with or prevents the reception of a signal or information. We distinguish 2 types of noise.
Radiant noise. This is EMI caused by electronic devices and specifically things as motors or moving parts. Also LED lights or metal frames can cause EMI. Some examples of parts that create this are : Refrigerator, air conditioner, washing machine, treadmill, medical devices, light, furniture with metal frames, electrode cables, elevator.
Power noise. This can be caused by incorrect power grid construction. Incorrect ground, improper materials used etc. The InBody can be influenced by this. Also if the InBody is sharing its outlet ( or circuit ) with multiple devices that are generating noise this can travel to the device.
Characteristics of noise
Considering its nature, Noise can impede with the device is very different and multiples way. Including but not only :
- Intermittently (or always)- TR impedance was reversed.
- Results sheet was not printed. (power noise) - Strange and inconsistent impedance readings
- Error message related measurement : “Wipe Hands and Feet Electrodes” “Check your thumbs and heels for proper contact” “The Test has stopped due to poor electrical contact” “Check Posture”
Overall strange behavior of the device (connexion issues, memory issues, etc)
Radiant Noise
Look around the InBody for any machines using motors or transmit at a certain frequency. :
Gym: treadmill, etc. – Product using AC/DC motorHospitals: High and low frequency Treatment Devices, MRI, etc. – Products that use specific frequency and high powerOther: refrigerator, warmer, air conditioner, compressor, multiplier, printer, PC, TV, audio amplifier, ad signboard (fluorescent light, neon sign), pin lighting, the building under the construction.Remove or power off the power code of the electromagnetic device suspected of noise within a radius of 5m except for the device and printer, and then perform an Inbody Measurement. If there is no equipment around, perform Inbody measurement after the change. This because it may be a bad phenomenon caused by noise from high voltage wires inside the floor or walls.
The above product installed around do not necessarily cause problems and may not occur due to the electrical environment of the installation site (e.g. ground connection status, electrical wiring, etc.). But it increases the probability of it happening
How to detect radiant noise
Use noise detector
If you have an electromagnetic tester, you can check the existence and nonexistence of electromagnetic waves by checking the surroundings of the Inbody Product.
If a phenomenon is reproduced:
Remove the power of an electromagnetic device with an electromagnetic wave DANGER one by one around the Inbody product to verify that the phenomenon disappears during human measurement, and to confirm that it is reproduced by running it again.
If the phenomenon cannot be reproduced:
Activate electronic devices with power turned off or not running around the Inbody product to verify whether the electromagnetic waves are DANGER and that the phenomenon is reproduced during human measurement. If the phenomenon is reproduced, turn it off and reconfirm the corresponding electromagnetic device.
If no noise generating electromagnetic device is found :
Check for Power Noise.Do continuous test with an RC jigMove the InBody to a different locationRemove the source of the radiant noise if possible.
Power Noise
Check whether the socket-outlet is ground connection or not. There are two ways to check whether a ground connection is present: there is way to check by a socket-socket-outlet ground tester or with a multi meter.
The way to check with an socket-outlet type ground tester
If you plug a socket-socket-outlet type ground tester into the socket-outlet you want to use, you can check whether the socket-outlet has ground with LED light Status on the tester.Since the shape of the socket-socket-outlet is differ from country to country, you should purchase the socket-outlet-shaped ground tester and use in each country.
With a multimeter
Set the multi meter to interchange measurement mode (~V) as shown in figure 1, and then insert the probe into the socket-outlet as shown in figure 2 to verify that the 220V voltage is outputted.
Hold one probe to the ground terminal as shown in figure 3 and 4 and measure the alternating current voltage at both left and right sides.
Power Grounded: Voltage close to 0V is measured on one side and 220V on the other.Without Power Ground: Measurement Value is measured by half (e.g. 91V / 109.1)
What can help with power noise
- Use a NF1500 noise filter, or use an S10 battery. Note that the NF1500 cannot always fix every power noise issue, depending on the intensity of the noise inteferences.- Check the socket-outlet connection Status- Separate Power: If peripherals are connected together to one multi-tab, connect the peripherals or the Inbody to another independent power and check the measurement value of the product.- Remove External Devices: Remove all cables connected to external devices such as printers, stadiometer, tonometer, and PC, and check measurement value. If there is no problem after removal, the noise is inpoured into the Inbody through the external device, and in this case, install the noise filter to prevent the noise from entering the Inbody.- If the problem is solved this way, the cause is power noise.
To keep in mind
Power noise
Where is the device plugged ?
Power noise, as will be explained later more in detail, can be very harmful for the device. It is therefore very important to keep that in mind when installing the device, and to ask ourselves the correct questions :
1 – Where is the device plugged ? Am I using a noise filter or sharing the plug with other appliances ?2 – How is the state of the power grid, is it grounded, does it look professional ? Does it look like there is multiple circuits?
If the device shares the same electrical circuits as multiples gym appliances (treadmill, e-Gym appliances, AC etc), it can cause an issue. So part of the installation should be spent on making sure the InBody device is at the optimal spot in the gym.
Examples to avoid :
Radiant noise
Similarly to power noise, radiant noise can be present. It shows similarities to power noise, but instead of coming through the electricity power plug, it comes through the air, and can go through thin walls.
Therefore it is also very important to have a look at other electrical machines around, even if they do not share the safe electricity plug. It is also important to educate the customer on this potential situation. We should make sure that the customer understand the importance of not placing any large electrical appliances very close to the device.
Non exhaustive list of what to look for : AC UnitNeon lightsTVMedical machinery (RMI, X-ray Imaging Machines, etc)Treadmills, Electrical indoor bikes
Bringing a noise detector is a good way to see where to, and not to place the device :