Capacitance Gap Measurement Probe System
Bring capacitance accuracy, high-speed response, built in calibration and temperature stability to your manufacturing floor at a cost effective price point.
Suitable for industrial deployment, this pre-calibrated capacitive gap sensor system provides highly accurate measurements to a grounded metal target. Capable of taking continuous or manual samples with analog or digital output for analysis or machine control. The large sample rate allows for insight into probe measurements providing an actionable data advantage. Achieve richer geometrical measurements by networking multiple probes together.
The system can continuously sample automatically with a on power-cycle or in a command mode. A “start sample” command is sent to the selected sensor to begin receiving data at a selected rate. A manual sample sequence command can be executed at any point for single samples. Data can be collected digitally or via the 0-10V / 4-20mA outputs of the control box.
Control Box
AP02
AP010
| Capacitance-based Technology | like eddy current, capacitance is insensitive to target material, self-contained absolute calibration |
| Standard PLC Interface | Easy to hook up to a PLC without any custom wiring |
| Networking Capable | Up to 4 sensors can be networked together per receiver, for rich geometrical measurement |
| Battery-operated Compact Form Factor | Can be easily placed in hazardous or unserviceable environments like in rotating machinery |
| Sample rate | Up to 1000 samples per second |
| Range | 2.5-10 mm |
| Digital Interface | RS485 Half-duplex |
| Digital Protocol | MODBUS RTU |
| Operating Temperature | 10-70°C |
Electrical Data
| APO2 | AP010 | |
| Ouput Current/Voltage | 0-10V or (4-20mA into 250 ohms) | 0-10V or (4-20mA into 250 ohms) |
| Response frequency | 1000Hz | 1000Hz |
| Operating voltage | 12-24Vdc | 12-24Vdc |
| Sensor head with amplifier | Diameter 8 mm | Diameter 30 mm |
| Sensing distance | 2.5 mm | 10 mm |
| Linearity | ±6 µm | ±30 µm |
| Resolution | 2.5 µm | 25 µm |
| Temperature drift | 250 ppm/ºC | 250 ppm/ºC |
Mechanical Data
| Mounting | M12X1 | M30X1 |
| Housing material | Stainless Steel | Stainless Steel |
| Target type | grounded, less than 10K ohm-cm³ | grounded, less than 10K ohm-cm³ |
| Product Weight | <150g | <300g |
| Overall Dimensions | Please see drawings | Please see drawings |
Environmental Data
| Operating Temperature | 10-70°C | 10-70°C |
Communication
| LSB (nm) | 1 nm | 1 nm |
| Digital Interface | RS-485 Half-duplex | RS-485 Half-duplex |
| RS-485 Speed (kbaud) | 19.2KBaud | 19.2KBaud |
| Product Weight | <150g | <300g |
| Digital Protocol | MODBUS RTU | MODBUS RTU |
Replacement of out-dated Eddy Current probe systems
- Eliminate drift due to temperature, by replacing eddy current probes with higher temperature stability capacitance.
- Gain more insight by networking wireless probes together to measure target geometry
- Built-in calibration replaces in-situ Eddy Current calibration saving installation time
- Immune to magnetic field interference
Measuring gap in rotating machinery
- The wireless capability and compact form factor, were designed specifically to measure gap in difficult to reach or inaccessible locations
- Optimized for machines that have a surface velocity up to 6000 SFM
- Capacitance-based technology allows measurement to any type of metal surface
MTI capacitance measurement system is based on the principle of parallel plate capacitor measurement. The electrical capacitance formed between a capacitance probe and a target surface varies as a function of the distance (gap) between these two surfaces. Capacitance-based measurement probes have long been employed as a means of non-contact measurement of electrically conductive materials. In a typical system, MTII’s capacitance probe acts as one of the plates and the grounded target the other plate. MTI’s amplifier converts the gap’s capacitance into an output voltage proportional to the gap. Capacitive measurements are very stable rivaling interferometer accuracy. The Capacitance is not adversely affected by temperature, humidity and pressure.
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