Vacuum and Cryogenics
CMCAT121RAR
Brooks Instrument 20 Torr CMC Capacitance Manometer
About this part
Brooks Instrument CMCAT121RAR is a compact, unheated CMC Series capacitance manometer configured for 20 Torr full scale, a 9-pin D-sub analog connection, a 4VCR female process fitting, Type A ±0.25% of reading accuracy, and RoHS compliance. This temperature-compensated absolute-pressure transducer provides a 0–10 VDC output linear with pressure and independent of gas composition
Configurations vary. Verify the exact unit before choosing a replacement.
Key Facts
Specifications
| Manufacturer | Brooks Instrument, LLC |
| Series | CMC Series |
| Base model | CMCA compact capacitance manometer |
| Measurement type | Temperature-compensated absolute pressure |
| Full-scale range | 20 Torr |
| Accuracy | ±0.25% of reading, RSS including hysteresis, linearity, and non-repeatability |
| Resolution | Limited by output noise, ≤0.0006% of full scale |
| Response time | 20 ms |
| Zero temperature effect | 0.005% of full scale per °C |
| Span temperature effect | 0.027% of full scale per °C |
| Operating temperature | 0 to 80°C |
| Compensated temperature | 0 to 50°C |
| Connector | 9-pin D-sub male |
| Input power | +12 to 30 VDC regulated |
| Output signal | 0–10 VDC, linear with pressure |
| Power consumption | <200 mW |
| Process fitting | 4VCR female |
| Process-exposed materials | Inconel sensor surfaces; the configured process fitting adds stainless steel |
| Overpressure limit | 45 psia |
| Weight | 0.3 lb (137 g) |
| Configured compliance | RoHS compliant |
What Does CMCAT121RAR Mean?
Brooks’ published ordering-code structure divides the identifier into six supported configuration segments.
| Segment | Field | Interpretation |
|---|---|---|
| CMCA | Base model | Compact capacitance manometer |
| T12 | Full-scale range | 20 Torr |
| 1 | Electrical connector | 9-pin D-sub with 0–10 VDC output |
| R | Process fitting | 4VCR female |
| A | Accuracy | ±0.25% of reading |
| R | Compliance | RoHS compliant |
9-Pin D-Sub Connections
The configured connector is the male 9-pin D-sub documented in the CMC installation manual.
| Pin | Function |
|---|---|
| 1 | + signal output |
| 2, 3, 5, 6, 7 | Not used |
| 4 | +12 to 30 VDC power supply |
| 8 | Signal-output common |
| 9 | Power-supply common |
Installation and Service Notes
- The gauge may be mounted in any orientation; vertical installation with the process tube facing down is recommended to reduce debris or condensable accumulation in the measurement cavity.
- Connect the female VCR fitting with a male VCR face-seal fitting and sealing gasket, tightening it to the fitting manufacturer’s specification.
- Use a common chassis ground for the gauge, power supply, and readout to minimize ground-loop effects.
- Only the zero adjustment is intended for field adjustment. Span adjustment and calibration require a certified reference standard and qualified personnel.
Documentation Downloads
Local PDF copiesPart Photos
2 imagesHistorical archive images for identification, labels, connectors, and condition reference, not current inventory.
Historical Listings & Prices
Historical listing data, not a current offerThe typical recorded price range is $850.00 to $850.00. Based on 1 archived listing record; not a current offer, appraisal, or confirmed sale price.
View archived listing titles
- Brooks Instrument Capacitance Manometer CMCAT121RAR