Fast response signal conditioners? Who needs ‘em? After all, most industrial signal conditioners / process transmitters purposely respond slowly – tenths of a second – to filter out things like flow noise, short term process variations and electrical noise. High speed signal conditioners aren’t even offered by some manufacturers.
That’s great for slow-changing continuous processes, but other applications need wide bandwidth or fast response signal conditioners. Operations such as stamping (impact force) and automated bottle filling (weight or flow) involve rapidly changing measurements. Control of robotics and position also often need fast response.
Test and experimental applications especially need high speed or high frequency signal conditioners. Examples include wind tunnels, combustion studies and projectile impact measurement. We even had an application involving impact measurements on aircraft drop tests.
We have experience. In response to a customer’s need, we redesigned JH Technology’s JH5000 Series DIN Rail Transmitter line to allow truly fast response.. Their Option HS is now available for most input types except AC and frequency. 1 millisecond (95%) response, 600 Hz (-3dB) bandwidth is standard but others are easily available. One customer repeatedly orders a high frequency signal conditioner with three poles at 30 KHz (3dB down at approximately 15 KHz).
Truly fast response signal conditioners potentially raise concerns about noise, phase shift and, if digital, sample rates and aliasing. Sharp cutoff multi-pole filters are great, but their large phase shifts at high frequencies can cause instability in some closed loop control applications. Slew rate limitations can be another high-frequency concern.
In a recent web search we found very few other companies offering high speed signal conditioners as fast as 1 msec. In most cases, those that did offered them only for higher level DC inputs.
Want more? See our white paper, “High Speed Signal Conditioners”, originally written for JH Technology and reprinted with their permission.