Frequency is an important parameter for an ac waveform. The frequency, in Hertz, is defined as the number of cycles per second. It can also be expressed as 1/T, where T is the time for one cycle. One period is the duration of one complete cycle, in seconds. (more...)
Most of us are familiar with Bluetooth as the connection from a cell phone to wireless earbuds or a remote speaker. This low-power communication protocol is simple to set up and use. It operates in the globally unlicensed industrial, scientific and medical (ISM) band from 2.40-2.48 GHz. (more...)
Current loops are a popular method for monitoring equipment and processes in industrial environments. Some of their advantages were discussed in an earlier posting. Additional advantages of the 4-20mA loop are:
– easy detection of an open loop, since the signal zero is represented by 4mA.
– the offset zero allows use of loop-powered devices that don’t require a separate power connection. (more...)
In residential applications, ground fault sensing is used to protect a building’s occupants from electric shock. Everyone is familiar with the ground fault interrupter (GFI), incorporated into a duplex outlet, that quickly opens the circuit when a fault is detected. The National Electric Code mandates their use in kitchens, bathrooms and other wet locations. (more...)
A question frequently posed to the Weschler Application team is: How to convert the output of an existing current transformer into a DC process signal? In North America, current transformers typically have a 5 amp secondary. (more...)