Trek 370 User Manual

Model 370

DC-Stable Electrostatic Voltmeter

Very High Speed of

!

Response: Less than
50 ms for a 1 kV

step

!

Measurement Range:

!

0 to ±3 kV DC or
Peak AC

!

Measurement

!

Accuracy: Better

The Trek Model 370 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 370 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.

An automatic gain control feature of the 370 eliminates the need
for manual adjustment when changing probes or when changing
the probe to measured surface separation.

The 370 also features one-step, push-button zeroing. When the
ZERO button on the front panel is pressed, the 370 automatically
adjusts the output to zero volts when the probe is coupled to a
known zero volt surface.

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
IEEE-488 compatible interface, 14-bit resolution, 12-bit accuracy,
and a programmable sampling period from 10 ms to 30 minutes.

Than 0.05% of Full
Scale

!

Automatic Gain

!

Control (eliminates
manual adjustment)

!

One Step, Push-

!

Button Zeroing

!

Precision Voltage

!

Monitor Output

!

Optional Data

!

Acquisition Module
(with an IEEE-488
compatible interface)

!

Compliant

!

The 370 can be operated on a bench top or, with optional
hardware, in a standard 19-inch rack.

Measurement and Power Solutions

www.trekinc.com

TM

Model 370 Specifications

Model 10/40A Specifications

All specifications are with a 3800E-2 probe at a probe-to-surface separation of 2 mm unless otherwise noted.

Performance Features (cont.) General

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 50 ms for a 1 kV step.

Stability

Drift with Time

Less than 150 ppm/hour,
noncumulative.

Drift with Temperature

Less than 100 ppm/°C.

Probe-to-Surface Separation

2 mm ± 1 mm (recommended).

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 370 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 Dimensions

A buffered output providing a low- 108 mm H x 223 mm W x 430 mm D
voltage replica of the measured (4.25" H x 8.75" W x 17" D).
voltage. 1/200, 1/300, 1/600, 1/1000
options available. (Offset Voltage and

Output Noise specifications vary
based on output scale factor.)

Scale Factor

1/100th of the measured voltage.

Offset Voltage (at 1/100th scale)

Less than 10 mV.

Output Noise (at 1/100th scale)

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 minutes.

Storage

32 Kbytes (16 Kbytes of data words).

Acquisition Start Signal

External trigger or IEEE-488 Talk
Enable or Group Trigger command.

Successive Data Acquisition

Internal timer or external trigger.

Interface Functions

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

Address

Switch selectable between 0 and 30.

Weight

5 kg (11 lb).

Digital Enable

BNC connector.

Voltage Monitor Output Connector

BNC connector.

Ground Receptacle

Binding post.

Power Requirements

Line Voltage

Factory set for one of two ranges:
90 to 127 V AC or 180 to 250 V AC,
at 48-63 Hz (specify when ordering).

Power Consumption

60 VA, maximum.

Operating Conditions

Temperature

0 °C to 40 °C.

Relative Humidity

To 85%, noncondensing.

Altitude

To 2000 meters

Certification and Compliance

TREK, INC. certifies that each Model
370 is tested and calibrated to
specifications using measurement
equipment traceable to the National
Institute of Standards and Technology.
A Certificate of Calibration
accompanies each instrument when it
is shipped from the factory.

Low-Voltage Safety Compliance

(EN 61010-1)

Overvoltage Category

CAT II: Local-level mains,
appliances, portable equipment.

Pollution Category

Degree 1: Operate in environments
where no pollution or only dry,
nonconductive pollution occurs.

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 . . . . . . . . . . . . . . . 370-1 Data Acquisition Module with IEEE-488 Compatible Interface . . . . . . . . . 16073

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

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

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

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

Line Voltage

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

180 to 250 V AC . . . . . . . . . . . . . . . . . . . . . . . (Part Number - Contact Factory)

Model 370 Optional Accessories

Probes

Standard Probe

Model 7000ER (end-viewing). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7000ER

Miniature Probes

Model 3800E-2 (end-viewing) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3800E-2

Model 3800S-2 (side-viewing) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3800S-2

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

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