BenchMaster 21CF30

Multi-Channel Filter/Amplifier System21CF30
  • Frequency  0.1 Hz to 51 kHz
  • 2550:1 cutoff span
  • -18 dB to +66 dB Gain (x0.125 to x2048)
  • Differential input
  • Switched 4mA IEPE source
  • Range of factory set filter responses
  • 16 channel 19" rack frame
  • Up to 8 frames per interface
  • Computer Controlled

 NOTE Not recommended for new integration in new measurement systems.
Alternatives are CardMaster 255G, BenchMaster 21M, and VBF 40 systems.

Channels  1-16 per rack ( up to 4 racks per system)
Control  RS 232 or GPIB
Frequency  0.1 Hz - 51 kHz
Gain  -18dB to +66 dB
Filters  Low pass or High pass.
Filter Responses  01 03 05 07 09 41
Input Coupling  AC / DC
IEPE  Yes 4mA 24V
Size  3U 19"
Power  90 -120 / 180-240 Vac 50/60Hz
 Optional 9 - 30 V DC, with AC 'power brick' 
Click Here for Full Specification

Filter Response

The 21CF30 covers a 2550:1 filter cut off frequency range, implemented as two ranges of 255:1 and 10:2550.
Four frequencies are available as standard: 0.1Hz, 1Hz, 10Hz and 20Hz. These give maximum frequencies of 255Hz, 2.55kHz, 25.5kHz and 51kHz respectively..
10 Hz Model10 - 2 550 Hz in steps of 10 Hz100 - 25 500 Hz in steps of 100 Hz
1 Hz Model 1 - 255 Hz in steps of 1 Hz 10 - 2 550 Hz in steps of 10 Hz
0.1 Hz Model 0.1 - 25.5 Hz in steps of 0.1Hz 1 - 255 Hz in steps of 1 Hz
20 Hz Model 20 - 5 100 Hz in steps of 20 Hz 200 - 51 000 Hz in steps of 200 Hz
More >>

Gain Range

A unity gain pre-trimmed differential stage feeds an amplifier with gain programmable from 0dB to 42dB in 6dB steps. After passing through the filter the signal is applied to an amplifier with gain from -18dB to 18dB in 6dB steps. In this way the output signal level can be adjusted to suit most conversion and recording systems.

Filter Response Types

Each 21CF30 card has a fixed response characteristic set at the factory. The card is available in several standard filter responses, lowpass or highpass. The most usual is  filter response 01 lowpass, for alias prevention.

Other Features

The 21CF30 is provided with programmable AC input coupling (-3dB @ 0.1Hz). In addition, a programmable 4mA current source for IEPE transducers is fitted, enabling the 21CF30 to offer a complete front end for this style of sensor. Input and outputs are via front panel BNC connectors.
Please note, the 21CF30 is one of our older products and is no longer recommended for inclusion in new design systems. See the alternatives listed near the top of this page.
Optional DC power is available. 
for more information please contact us.