Trek 370TR User Manual

Model 370TR

DC-Stable Electrostatic Voltmeter

High speed of response:

!

Less than 200 µs for a 1
kV step

!

Transparent probe

!

enables simultaneous
radiation and
measurement of
surfaces

!

Measurement range:

The Trek Model 370TR is a
precision electrostatic voltmeter
with the unique capability of
making noncontacting surface
voltage measurements in the
range of 0 to ±3 kV DC or peak AC.

The 370TR employs an electrostatic field-nulling technique which
achieves high DC stability and high measurement accuracy even if
the probe to measured surface spacing changes. This permits
measurements of either stationary or moving surfaces without the
need to establish fixed spacing to maintain accuracy.

The Model 3629A Transparent probe permits light to pass through
the probe to provide simultaneous radiation and measurement of
a surface. This is useful for photosensitive surface studies such as
‘time of flight’ measurements of photoconductor surfaces.

A D i gital Ena ble conne ction per mits remote ON/ OFF
measurement capability. An automatic gain control feature of the
370TR eliminates the need for manual adjustment when changing
probes or when changing the probe to measured surface
separation. The 370TR also features one-step, push-button
zeroing. When the ZERO button on the front panel is pressed, the
370TR automatically adjusts the output to zero volts when the
probe is coupled to a known zero volt surface.

!

0 to ±3 kV DC or peak AC

!

Measurement accuracy:

!

Better than 0.05% of
full scale

!

Automatic gain control

!

eliminates manual
adjustment

!

One step, push-button

!

zeroing

!

Precision voltage

!

monitor output

!

Remote ON/OFF

!

operation capability

!

Optional data acquisition

!

A precision voltage monitor provides a low-voltage replica of the
measured electrostatic voltage for external monitoring purposes,
or for use as a feedback signal in a closed-loop system.

An optional data acquisition module is available, featuring an IEEE­488 compatible interface, 14-bit resolution, 12-bit accuracy, and a
programmable sampling period from 10 ms to 30 minutes.

Measurement and Power Solutions

www.trekinc.com

module

!

compliant

!

TM

Model 370TR Specifications

All specifications are with a 3627 or 3629A probe at a probe-to-surface separation of 2 mm unless otherwise noted.

Model 10/40A Specifications

Performance Features (cont.) General (cont.)

Measurement Range

0 to ±3 kV DC or peak AC.

Measurement Accuracy

At the Voltage Monitor

Better than ±0.05% of full scale.

At the Voltage Display

Better than ±0.1% of full scale
±1 count, referred to the voltage
monitor.

Speed of Response (10% to 90%)

Less than 200 ms for a 1 kV step.

Stability

Drift with Time

Less than 150 ppm/hour,
noncumulative.

Drift with Temperature

Less than 100 ppm/°C.

Features

Zero Control

A momentary push-button switch to
produce zero volts output when the
probe is coupled to a known zero volt
surface.

Automatic Gain Control

The 370TR automatically optimizes the
gain of the AC response when
changing the type of probe
being used or when changing the
probe-to-surface separation.

Voltage Display

4-character, 7-segment LED display.

Range 0 to ±3000 V.
Resolution 1 V.
Zero Offset ±1 count, referred to

the voltage monitor.

Sampling
Rate 2.5 readings per

second.

Voltage Monitor Output

A buffered output providing a low­voltage replica of the measured
voltage.
Scale Factors

1/100th of the measured voltage.
(1/200, 1/300, 1/600, 1/1000
options available.)

Offset Voltage

Less than 10 mV.

Output Noise

Less than 20 mV rms (measured
with the true rms feature of the
Hewlett Packard Model 34401A
digital multimeter).

Output Impedance

Less than 0.1 W.

Output Current Limit

±10 mA

Digital Enable

An open collector, TTL compatible
input to enable or disable the
measurement. A TTL high
will disable the measurement, while a
TTL low will enable the measurement.

Data Acquisition Module (optional)

Provides data output using an IEEE­488 compatible interface.
Resolution 14 bit.
Accuracy 12 bit.
Sampling Period

Programmable from 10 µs to 30 min.

Storage 32 Kbytes

(16 Kbytes of data words).

Interface Functions

SH1, AH1, T6, L4, SR1, RL1, PP0,
DC1, DT0, C0, E2.

Address

Switch selectable between 0 and 30.

General

Dimensions

108 mm H x 223 mm W x 430 mm D
(4.25" H x 8.75" W x 17" D).

Weight

5 kg (11 lb).

Digital Enable

BNC connector.

Voltage Monitor Output Connector

BNC connector.

Ground Receptacle

Binding post.

Power Requirements

Line Voltage

90 to 127 V AC at 48-63 Hz
(180 to 250 V AC at 48-63 Hz
option available).

Power Consumption

60 VA, maximum.

Operating Conditions

Temperature

0 °C to 40 °C.

Relative Humidity

To 85%, noncondensing.

Probes

Probe-to-Surface Separation

2 mm ± 1 mm (recommended).

Model 3629A (Transparent)

Body Shape Square.
Aperture Size 5.3 mm diameter.
Aperture Location Side.
Dimensions

11.8 mm sq. x 65.6 mm L.

Model 3627

Body Shape Square.
Aperture Size 1.5 mm x 3.0 mm.
Aperture Location Side.
Dimensions

11.8 mm sq. x 76.2 mm L.

Certification and Compliance

TREK, INC. certifies that each Model
370TR is tested and calibrated to
specifications using measurement
equipment traceable to the National
Institute of Standards and Technology.

Copyright Ó 2011 TREK, INC.
All specifications are subject to change.
1122/DEC

Item Part No. Item Part No.

Electrostatic Voltmeter with 1/100 Monitor Output Ratio . . . . . . . . . . . . 370TR-1 Data Acquisition Module with IEEE-488 Compatible Interface . . . . . . . . . 16073

Electrostatic Voltmeter with 1/200 Monitor Output Ratio . . . . . . . . . . . . 370TR-2 603RA Full-Rack Mounting Kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 603RA

Electrostatic Voltmeter with 1/300 Monitor Output Ratio . . . . . . . . . . . . 370TR-3 604RA 1/2 Rack Mounting Kit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 604RA

Electrostatic Voltmeter with 1/600 Monitor Output Ratio . . . . . . . . . . . . 370TR-6

Electrostatic Voltmeter with 1/1000 Monitor Output Ratio . . . . . . . . . . 370TR-10

Line Voltage

90 to 127 V AC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (Part Number)-L

180 to 250 V AC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (Part Number)-H

Model 370TR Optional Accessories

Probes

Transparent Probe

Model 3629A (side-viewing). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3629A

Standard Probe

Model 3627 (side-viewing) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3627

TREK, INC. • 190 Walnut Street • Lockport, NY 14094 • USA • 800-FOR TREK

(fax) • www.trekinc.com • [e-mail] 716-438-7555 • 716-201-1804