Vacuum and Cryogenics
CMCAT311RAR
Brooks Instrument 1000 Torr Unheated Capacitance Manometer
About this part
Brooks Instrument CMCAT311RAR is a compact, unheated CMC Series capacitance manometer for absolute vacuum-pressure measurement. Its model code specifies 1000 Torr full scale, a 9-pin D-sub analog interface, a 4 VCR female process fitting, Type A ±0.25% of-reading accuracy, and RoHS compliance. The transducer provides a linear 0–10 Vdc pressure output independent of gas composition
Configurations vary. Verify the exact unit before choosing a replacement.
Key Facts
Specifications
| Manufacturer | Brooks Instrument, LLC |
| Series | CMC |
| Model code | CMCAT311RAR |
| Measuring principle | Capacitance diaphragm gauge |
| Pressure type | Absolute |
| Full-scale range | 1000 Torr |
| Accuracy | Type A: ±0.25% of reading, RSS including hysteresis, linearity, and non-repeatability |
| Resolution | Limited by output noise to ≤0.0006% of full scale |
| Zero temperature coefficient | 0.005% of full scale per °C |
| Span temperature coefficient | 0.027% of full scale per °C |
| Response time | 20 ms |
| Connector | 9-pin male D-sub |
| Input power | +12 to 30 Vdc regulated |
| Output signal | 0–10 Vdc, linear with pressure |
| Power consumption | <200 mW |
| Process connection | 4 VCR female |
| Exposed materials | Inconel; the configured fitting adds stainless steel |
| Overpressure limit | 45 psia |
| Weight | 0.3 lb (137 g) |
| Internal volume | <6.0 cc |
| Device temperature | Ambient; unheated |
| Operating temperature | 0 to 80°C |
| Compensated temperature | 0 to 50°C |
| RoHS | Compliant, model-code option R |
What Does CMCAT311RAR Mean?
The compact identifier consists of six documented CMC ordering fields.
| Segment | Field | Interpretation |
|---|---|---|
| CMCA | Base model | Compact capacitance manometer |
| T31 | Full-scale range | 1000 Torr |
| 1 | Electrical connector | 9-pin D-sub with 0–10 Vdc output |
| R | Fitting | 4 VCR female |
| A | Accuracy | ±0.25% of reading |
| R | Compliance | RoHS compliant |
9-Pin D-Sub Pinout
Connector functions documented for the configured 9-pin male D-sub option.
| Pin | Function |
|---|---|
| 1 | + signal output |
| 2, 3, 5, 6, 7 | Not used |
| 4 | Power supply +Vdc |
| 8 | Signal-output common |
| 9 | Power-supply common |
1000 Torr Operating Guidance
Range-specific guidance from the CMC installation and operation manual.
Installation and Service Notes
Installation practices applicable to the configured CMC transducer.
- The transducer may be mounted in any orientation; vertical installation with the process fitting downward is recommended to reduce debris or condensable-material accumulation.
- Connect the female VCR fitting using a compatible male VCR face-seal fitting and sealing gasket.
- Use a common chassis ground for the transducer, power supply, and readout to minimize ground-loop errors.
- Periodic zero adjustment is the normal field-maintenance requirement. Span adjustment requires a calibrated reference 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 CMCAT311RAR