MEASURING INSTRUMENTS
Function generator: a known test signal
Create a sine, square or triangle and explore frequency, amplitude, offset and load.
The principle
A function generator produces a selected waveform. Frequency is cycles per second and period T = 1/f. Vpp is the difference between maximum and minimum; offset shifts the waveform. A 4 Vpp sine wave with 1 V offset goes from −1 to +3 V. Many generators have a 50 Ω source impedance. If its levels are specified for a 50 Ω load, a high-impedance load can see approximately twice both amplitude and offset. Consult instrument limits.
An example
Set a 1 kHz sine wave, 4 Vpp and zero offset as specified for a 50 Ω load. The period is 1 ms. Compare the simulated output under 50 Ω and high-impedance loads; verify actual levels with a scope.
Important
A signal generator is not a power supply for motors or unknown installations. Check common ground, input limits, output impedance and the load. Do not connect it directly to an active fieldbus.