Trek 875 User Manual
Model 875
Electrostatic Voltage Sensor
! Measurement Range of
0 to ±500 V DC or peak AC
!
! Accuracy is Independent of
Probe-to-Measured Surface
Spacing
!
! Voltage Monitor with an
Accuracy Better than
±0.5% of full scale (F.S.)
!
! 4-20 mA Current Monitor
!
! Speed of Response < 25 ms
Trek’s Model 875 Electrostatic Voltage Sensor is designed for in-line monitoring
of electrostatic charge build-up, which if left unchecked, can disrupt
manufacturing processes or cause product degradation and early life failure of
semi-conductors and other charge-sensitive components. Excellent for
monitoring static charge levels within manufacturing equipment such as
conveyors, handlers, and other tools, the 875 features an automatic calibration
technique to maintain high accuracy and speed over wide variations of spacing
between the non-contacting measurement probe and the surface under test.
Other features include a voltage measurement range of ± 500 V DC or peak AC,
accuracy of ±0.5%, speed of 25 ms, and low noise of 1% rms of full scale.
Buffered output voltage and current monitors (4 to 20mA) are provided for remote
monitoring and alarm purposes. The unit is powered by +24 V DC and is housed in
a standard DIN package to enable standardized mounting.
!
! Enclosure Mounts on 35mm
DIN RAIL
!
! TTL Digital Enable Input
!
! TTL Fault Warning Flag
Output
!
! compliant
PERFORMANCE FEATURES PROBE
At 4 mm ±1 mm probe-to-surface
distance
Measurement Range
0 to ±500 V DC or peak AC.
Measurement Accuracy
At the Voltage Monitor Output
Better than ±0.5% of F.S.
At the Current Monitor Output
Better than ±3% of F.S.
Current Monitor (4-20 mA)
Linearly related to the measured
input voltage.
Scale Factor (+4 mA to +20 mA
representing a -500 V to +500 V):
Speed of Response (10% to 90%)
Less than 25 ms for a 0 to ±500 V
step change.
-500 V = 4 mA,
0 V = 12 mA,
+500 V = 20 mA.
Voltage Monitor Output
A buffered low-voltage replica of the
measured voltage.
Scale Factor
1 V / 50 V.
Noise
Less than 1% rms of full scale.
Digital Enable
An external control TTL signal.
A TTL HIGH (or open) will disable
all internal power supplies.
A TTL LOW will provide normal
ESVM operation.
Fault Warning Output
A TTL output signal. A TTL HIGH
indicates normal operation of the
Model 875. A TTL LOW indicates
a fault condition such as: out of
range operation (circuit is
measuring a voltage greater than
±500 Volts), failure of the probe,
or circuit malfunction.
Probe Dimensions
5.6 mm square x 50 mm L
Aperture Orientation / Body Type
Side / Square.
Probe Cable Length
3.0 ±0.1 meters.
Recommended Probe-to-Surface
Separation
4 mm ±1 mm.
An optional probe holder fixture is
available - contact factory.
Power Supply Voltage
+24 V DC ±10%.
Power Supply Current
150 mA, maximum.
Power ON Indicator
A LED indicator illuminates when
power is applied to the unit.
Measurement and Power Solutions
www.trekinc.com
GENERAL
TM
190 Walnut Street • Lockport, NY 14094 • 800-FOR TREK fax • sales@trekinc.com 716-438-7555 • 716-201-1804
Copyright Ó 2012 TREK, INC. All specifications are subject to change. 1225/DEC
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