GPE 31611 Capacitance Center Sensor

The Model 31611 Capacitance Sensor is designed for intermediate center guide applications where large width variations are encountered and accuracy requirements are not critical. This unique sensor will operate in clouded, dirty, and high-temperature environments, where photoelectric sensors normally cannot be used. It requires little or no maintenance.

Two types of sensors are available; a C-frame type sensor with a fixed gap of 18 inches, and a Separate Channel type sensor, which can be mounted to provide adequate clearance for most installations (18 inches maximum typical).

The sensors function within a tuned circuit designed so that any change in lateral movement of the strip will cause a capacitance change which provides an error signal for the controller. Materials to be guided with the Capacitance Sensor must be metal or a metal mesh and preferably should be grounded for best results.

The Model 33130 Capacitance Centerguide Controller is required for sensor operation. It is designed to accept capacitance changes from the sensors and provide the control signal required. Strip position errors are detected in the tuned circuit and rectified and as a result, the controller DC output is proportional to the error signal. Output signals are intended to be used with an Electro-hydraulic Controller or a Powerpulse Hydraulic Controller.

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  • Reliability: Operates in dirty and high-temperature environments with little or no maintenance.
  • Positive: Sensor operates into a high-frequency tuned circuit which rejects all other frequencies
  • Accuracy: Less than ±1/8″ per 6″ of strip width change when ± adjusted in accordance with instructions
  • Rugged Construction: Heavy-duty aluminum channel construction for the sensor makes it virtually indestructible.



  • Input: 28 volts RMS at 165 K Hz from Model 33130 Controller
  • Output: Variable capacitance signal to Model 33130 Controller
  • Sensitivity: .06 pf per/in. of lateral strip shift for 18” sensor gap. Separate mounted sensor Inversely proportional to gap.
  • Centerline Shift: Less than ± 1/8” per 6” of width change and 10° F ambient temperature change when properly adjusted.
  • Ambient Temperature Range: Minus 50° F to 200° F
  • Electrical Connections: 40 feet coaxial cable provided for each sensor.
  • C-Frame: 6” wide aluminum channel mounted on high strength post-type insulator.
  • Separate Channel: 6” wide aluminum channel. Each channel mounted on a high-strength post-type Insulator.
  • Weight: C-Frame - 55 Ibs. (18” sensor); C-Frame - 80 Ibs. (36” sensor); Separate Channel - 20 Ibs. (18” sensor); Separate Channel - 25 Ibs. (36” sensor)


  • Input Power:
    117 VAC, ±10%, 50/60 Hz, 70 VA (Electrohydraylic Controller)
    117 VAC, ± 10%, 50/60 Hz, 150 VA (Powerpulse Controller)
  • Input Signal: Capacitance change from sensors: Minimum - 650 pf; Maximum - 900 pf
  • Outputs: 0 to ± 10 VDC Into 250 ohms minimum (Proportional Speed Floating - PSF)
  • Power pulse: On-Off 105 VDC into 600 ohms minimum (Predictive Position Feedback - PPF); On-off 105VDC into 600 ohms minimum (TwoSpeed Floating - TSF)
  • Electrohydraulic: +10, 0 or -10 VDC Into 250 ohms (Predictive Position Feedback· PPF)
  • Detection Sensitivity: Nominal 80 mv/pf rectified from the tuned circuit. Equivalent to 50 mv/in. of lateral strip movement of the sensor.
  • Frequency Response: 0-40Hz
  • Gain: Basic DC amplifier is adjustable in two ranges from 4 to 4000. (This is equivalent to 0.2 volts per/in. to 200 volts per/in. when operating from sensor. )
  • Ambient Temperature: +32°F to 120°F; 10 - 95%
  • Indicator: 10-0-10 volt output meter.
  • Construction: 12” x 14” JIC enclosure
  • Weight: 25 lbs.
  • Connection: 1” threaded conduit
  • Outputs for Manual Operation Electrohydraulic Controller: ± 15 VDC, 150 ohms minimum load resistance
  • Power pulse Controller: 105 VDC, 600 ohms minimum ioad resistance
  • Output for Remote Bias: ± 6.2 VDC, regulated, 50K ohms load

Download Datasheet: GPE 31611 Capacitance Center Sensor