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  • Range of Standard Filter Responses
  • 2 Independent Channels
  • 2 Rugged Racks, AC or Optional DC power 
  • Single ended / Differential / IEPE inputs
  • BNC inputs & outputs
  • Gain to +60dB
  • Output attenuation, if required
  • 3 cut-off frequencies with 1200 filter modules
  • 255 cut-off frequencies with 1600 filter modules
  • Usually ex-stock
Kemo compact mini rack with 1 CardMaster 21.2 signal filter Kemo 19" rack with 16 CardMaster 21.2 dual channel filter cards
2 channel mini rack 16 channels in 19" rack
rack can take up to 36 channels

The Kemo CardMaster 21.2 is a filter card designed for fixed frequency filtering applications requiring fixed settings or occasional adjustment of cut-off frequency.  CardMaster 21.2 is a member of the Series 21 family of signal conditioning components and can be used in mixed systems comprising different cards from the Series 21 filters.
Up to 18 CardMaster 21.2's can be fitted to the Kemo 21.18 3U 19" rack, or 1 card in the 21.1 minirack as shown above.

The CardMaster 21.2 replaces several older Kemo filter cards and uses the 1200 or 1600 Series filter modules to provide a flexible solution for fixed frequency applications. CardMaster 21.2 systems are usually supplied fitted in a rack, configured and tested to your requirements. For low channel count systems,<8 channels, it may be worth looking at the DIN Rail filters.

Summary Specification

Channels 2 per card - common zero volt
Control On board switches or selectable components
Frequency Semi-fixed, user specified
Gain 0 - +60dB, with output attenuation 
Filters 1200 and 1600 series filter modules
Filter Responses Defined by filter modules
Input Coupling AC / DC, Single ended/differential
IEPE 1 - 10mA 24V selectable
Size 1 Series 21 slot (100x220mm Eurocard)
Racks, Size and Weight 21.18 Rack(19") - up to 36 channels, 420 x 155 x 350mm (16.6 x 6.1 x 13.8"), 11 kg, (24 lb) maximum.
21.5 Rack - up to 10 channels, 153 x 155 x 350mm (6 x 6.1 x 13.8"),  3.6 kg (8 lb) maximum. Special order
21.1 Minirack - up to 2 channels, 44 x 116 x 270 mm (1.7 x 4.6 x 10.7") 1 kg ( 2.2 lb) maximum.
Power 21.18 rack  90 -120/180-240 Vac 50/60Hz - Optional DC power
21.1 minirack 9 - 30V DC power

Frequency Range
When fitted with Kemo 1200 Series filter modules the cut-off frequency of a CardMaster 21.2  can be be set to 3 values. fca, fcb, and fc a+b, selected by switches on the CardMaster 21.2. (These cut-off's are usually factory set, however full instructions are included for the user to change these)
When fitted with Kemo 1600 Series filter modules the cut-off frequency can be set by on board dip switch to give 255 steps of filter cut-off. ( Note 1600W filter modules are not recommended for use on CardMaster 21.2)

Inputs and Gain
From our experience of signal filtering we have included a versatile set of input configurations and gain on the CardMaster 21.2. Each channel can be independently configured.
Inputs - AC or DC coupling, set by on board switches.
Input Mode - Single ended or differential, set by on board switches.
Transducer Power - current source for IEPE transducers, 24V 1-10 mA, set by user selectable resistor.
Input Gain - up to + 60dB. Set by single on board resistor. Kemo use industry standard top quality instrumentation amplifiers.
Trims - Gain and DC offset can be trimmed by multi-turn pots on the board.
Output attenuation - if required the output can be passively attenuated.

Series Connection 
In some cases, for bandpass filtering, the two channels can be internally connected in series.

DC Power
DC power, 9-30V DC input is available as an option for the 21.18 racks, with an AC 'power brick' to power the unit from mains when available. Please check our page about DC Power.