Desco 19493 Operation And Maintenance

TECHNICAL BULLETIN TB-3041

Ionization Test Kit
Operation and Maintenance

“When any object becomes electrostatically charged,

there is an electrostatic eld associated with that charge.

If an ESDS (ESD sensitive) device is placed in that

electrostatic eld, a voltage may be induced on the

device. If the device is then momentarily grounded, a
transfer of charge from the device occurs as a CDM
(Charged Device Model) event. If the device is removed

from the region of the electrostatic eld and grounded

again, a second CDM event will occur as charge (of

opposite polarity from the rst event) is transferred from
the device.” (Handbook ESD TR20.20 section 2.7.5 Field

Induced Discharges)

“All nonessential insulators such as coffee cups, food
wrappers and personal items shall be removed from the
EPA.

Figure 1. Desco 19493 Ionization Test Kit

Description

The Desco Ionization Test Kit allows the 19492 Digital

Static Field Meter to be used to measure the o󰀨set

voltage (balance) and charge decay of ionization
equipment. The Test Kit also includes a Charger used to
place a ±1000V charge on the 19441 Conductive Plate,
making it possible to also measure the discharge times
of air ionization equipment per ANSI/ESD SP3.3 Periodic

Verication of Air Ionizers. The 19493 Ionization Test Kit

includes the 19492 Digital Static Field Meter, providing a

highly portable and cost e󰀨ective means of verifying the

performance of a wide variety of ionization equipment.

Note: The Digital Static Field Meter is designed to
operate only with the 19493 Ionization Test Kit. It is not
compatible with other brands.

Although not as accurate, the Desco Ionization Test Kit
has been designed to make measurements that
correspond to those made by using a charged plate
analyzer and ANSI/ESD S3.1. The Ionization Test Kit
provides convenience and portability to test per ANSI/

ESD SP3.3 Periodic Verication of Air Ionizers or
Compliance Verication ESD TR53. We recommend

the EMIT 50571 Charged Plate Analyzer if precise
measurements are required.

The Ionization Test Kit includes a slide-on isolated
Conductive Plate, a ±1000 volt Charger and a durable
thermoplastic carrying case with custom cut-outs for all
of the above components along with the Digital Static
Field Meter.

The ESD program shall include a plan for handling
process-required insulators in order to mitigate
field-induced CDM damage.

If the field measured on the process required insulator
is greater than 2000 volts/inch and the process required
insulator is less than 30 cm (12 inches) from the ESDS
item, steps shall be taken to either:

A) Separate the required insulator from the ESDS item
by a distance of greater than 30 cm (12 inches); or

B) Use ionization or other charge mitigating techniques
to neutralize the charge.

If the field measured on the process required insulator
is greater than 125 volts/inch and the process required
insulator is less than 2.5 cm (1 inch) from the ESDS
item, steps shall be taken to either:

A) Separate the required insulator from the ESDS item
by a distance of greater than 2.5 cm (1 inch); or

B) Use ionization or other charge mitigating techniques
to neutralize the charge.

NOTE: The accurate measurement of electrostatic fields
requires that the person making the measurement is
familiar with the operation of the measuring equipment.
Most hand held meters require that the reading be taken
at a fixed distance from the object. They also normally
specify that the object has a minimum dimension of
fixed size in order to obtain an accurate reading.” (ANSI/
ESD S20.20-2014 section 8.3.1 Insulators)

Made in the

United States of America

DESCO EAST - One Colgate Way, Canton, MA 02021-1407 • [phone] • Website: Desco.com

TB-3041 Page 1 of 6

April 2018

DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 • [phone]

© 2018 DESCO INDUSTRIES, INC.

Employee Owned

Packaging

1 Digital Static Field Meter
1 Conductive Plate
1 Charger
2 9V Alkaline Batteries
1 Carrying Case

1 Certicate of Calibration

Features and Components

DIGITAL STATIC FIELD METER

See technical bulletin TB-3040 for information on the
Digital Static Field Meter that is included in the 19493
Ionization Test Kit.

A. Output Contact: The output contact is connected to
an internal power source. When the touch plate located
underneath the unit is connected to ground, the output
contact will provide a charge of the indicated polarity.
The charger is designed so that an operator can press
the rocker switch and touch the plate simultaneously

with the ngers of the same hand.

B. Rocker Switch: Press and hold to select the polarity
that will be provided at the Output Contact.

C. Touch Plate: Make contact with the touch plate while
pressing down the rocker switch to provide voltage to the
Output Contact. The operator must be properly
grounded during use.

CHARGER

D. Battery Compartment: Slide the cover down to open

the 9V battery compartment.

A

Operation

TAKING OFFSET VOLTAGE (BALANCE)
MEASUREMENTS

The Ionization Test Kit has been designed to match the
compact size and hand held convenience of the Digital
Static Field Meter. Use the following procedure to verify

the o󰀨set voltage (balance) of air ionization equipment.

B

This quick and easy procedure will help determine if
the piece of ionization equipment is working within the

manufacturer’s specications or user requirements.

It is extremely important that ionizers be checked

regularly for o󰀨set voltage (balance) and discharge

times. An ionizer operating in an out-of-balance

state can place a charge on sensitive electronic

FRONT VIEW

components or assemblies.

Note: The Digital Static Field Meter is built in a

conductive case. The instrument senses the di󰀨erence in

potential between the case (and the person holding the
case / ground connection) and the surface under test.
Ensure that the person using the instrument is wearing
a wrist strap and grounded to achieve more accurate
measurements.

BACK VIEW

Figure 2. Charger features and components

DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 • [phone]

DESCO EAST - One Colgate Way, Canton, MA 02021-1407 • [phone] • Website: Desco.com

TB-3041 Page 2 of 6

C

INSTALLING THE ISOLATED PLATE ASSEMBLY

The Digital Static Field Meter’s case has two slots along
its sides. The top slot is closest to the face of the
instrument. Slide down the tabs of the Conductive Plate

D

plate into the top slot of the Meter’s case as far as they
go (see Figure 3).

© 2018 DESCO INDUSTRIES, INC.

Employee Owned

Figure 3. Installing the 19441 Conductive Plate

ZERO THE METER

Turn the Meter on by pressing the POWER button. Press
the RANGE / ZERO button to set the Meter to the 2 kV

(3 decimal places) range. Make contact between the top
of the Conductive Plate and a grounded surface. Press

and hold the RANGE / ZERO button until the Meter

displays “.000”.

Thousands
Hundreds
Tens

Figure 4. Reading the Digital Static Field Meter while in
the ±20 kV range

Hundreds
Tens
Ones

MAKING A MEASUREMENT

Locate the Test Kit in an ionized environment at the
appropriate distance from the device under test. The

static eld displayed is the actual balance of the ionizer
or voltage o󰀨set. The display will indicate “1” or “-1”

when the Meter is over-ranged. Change the range of the
unit if necessary.

Note: When testing pulsed ionizer systems, the voltage
displayed is constantly changing. This pulse rate may be
faster than the display update rate of the Field Meter,
therefore the displayed voltage is an average of the
actual voltage. The output of the Field Meter is useful in
this situation for more accurate measurements.

Figure 5. Reading the Digital Static Field Meter while in
the ±2 kV range

DESCO EAST - One Colgate Way, Canton, MA 02021-1407 • [phone] • Website: Desco.com

DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 • [phone]

TB-3041 Page 3 of 6

© 2018 DESCO INDUSTRIES, INC.

Employee Owned

18"

12"

Figure 6. Auditing ionization equipment with the Digital
Static Field Meter and Conductive Plate (Ref: ANSI/ ESD
SP3.3)

HOLDING THE LAST READING

With the meter positioned 1 inch from the object being
measured, press the HOLD button. This will freeze the
reading from the object on the display and the analog
output signal. This feature allows the operator to move
the meter where it may be more easily read or saved for
later reference.

POLARITY SELECTION

The top of the rocker switch is labeled “+”, and the
bottom is labeled “-”. To provide a POSITIVE voltage
output, touch the plate located underneath the charger,
and press the switch forward at the same time. To

provide a NEGATIVE voltage output, touch the plate

located underneath the charger, and press the switch
downward at the same time.

Note: For the Charger to work correctly, the operator
and Field Meter must be properly grounded. A ground
path to the touch plate must exist.

IONIZER DISCHARGE TIME MEASUREMENTS

Use the Field Meter with the conductive plate in the
appropriate location for measurements.

POSITIVE DISCHARGE TIME MEASUREMENTS

To provide a POSITIVE voltage output, touch the plate
located underneath the Charger, and press the switch
forward at the same time. Momentarily touch the
Charger’s output terminal to the conductive plate
attached to the Field Meter. The meter reads
approximately +1.10 kV. By using a stop watch or other
timing device, determine the time needed for the
voltages to decrease from +1.10 kV to +0.10 kV. This is
the positive discharge time.

Note: The red ranging lights will be o󰀨 while the meter is

in HOLD mode. It is advised to do this between
measurements to prolong battery life.

ANALOG OUTPUT

The analog output jack labeled “OUT” on the face of the
meter accepts a standard 2.5 mm monaural phone plug
and is provided so the output of the Digital Static Field
Meter may be connected to an oscilloscope, strip chart
recorder, external meter or other device. The voltage at
this output is 1/1000th (±2 kV range) or 1/10,000 (±20
kV range) of the measured voltage. Contact Customer
Service for more information.

TAKING DISCHARGE TIME MEASUREMENTS

In order to verify that an ionizer is operating properly it is
also important that its ability to neutralize or discharge
static electricity is measured. The following procedure
will measure an ionizer’s discharge time:

OPERATING THE CHARGER

The Charger has a momentary rocker-switch that powers
the unit. Holding the switch forward / backward supplies
power to the output terminals.

Figure 7. Charging the Conductive Plate on the Digital
Static Field Meter

NEGATIVE DISCHARGE TIME MEASUREMENTS

To provide a NEGATIVE voltage output, touch the plate

located underneath the Charger, and press the switch
downward at the same time. Momentarily touch the
Charger’s output terminal to the conductive plate
attached to the Field Meter. The meter reads
approximately -1.10 kV. By using a stop watch or other
timing device, determine the time needed for the
voltages to decrease from -1.10 kV to -0.10 kV. This is
the negative discharge time.

DESCO EAST - One Colgate Way, Canton, MA 02021-1407 • [phone] • Website: Desco.com

DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 • [phone]

TB-3041 Page 4 of 6

© 2018 DESCO INDUSTRIES, INC.

Employee Owned

IMPORTANT: A ground path must be provided between
the touch plate of the Charger and the ground reference
of the Field Meter. This is normally provided by holding
the Charger in one hand and the Field Meter with
Conductive Plate in the other.

Maintenance

The Digital Static Field Meter is factory calibrated and no
maintenance is required. If for any reason you believe
the Meter is not working correctly, please contact Desco
Customer Service. CAUTION - There are no user
serviceable parts. Any unauthorized service will void the
warranty and result in additional repair charges.

Note: This Meter is a precision instrument and should
not be subjected to dropping as that would void the
warranty.

BATTERY CHECK

The battery should be replaced when “BAT” is indicated
on the display. Always replace the battery with a 9V
alkaline or equivalent battery in order to remain CE
compliant.

BATTERY REPLACEMENT

The Digital Static Field Meter operates from a standard 9
VDC alkaline battery. Battery life is in excess of 50 hours
under normal use. When the battery voltage drops below

6.5 V, “BAT” will appear on the display. To change the
battery, slide the battery cover down at the back of the
Meter and remove the battery from the

battery clip. Replace the battery with a fresh one and

reinstall the battery cover. The battery should be
removed from the Meter if its is to be stored for an
extended period of time.

The battery in the Charger should be replaced annually
or when it is unable to provide approximately ±1100V.

CLEANING

It is important to keep the insulators on the adapter plate
clean and free of contaminates that may cause surface
leakage. To test the performance of the adapter plate,
charge the plate and note the discharge rate in a
nonionized area. The self discharge rate to 10% of

original voltage should not be less than ve minutes.

The area around the aperture of the Digital Static Field
Meter must be kept clean to ensure accurate, drift-free
readings. Never touch the aperture with anything. To
remove dust or other particulate matter, use low­pressure instrument-grade air. To remove more severe

contamination, spray or ush with the smallest practical

amount of clean technical-grade of isopropyl alcohol.
Then allow the instrument to air dry for several hours.

Specications

STATIC FIELD METER

Performance

Measurement Range (switch selectable)

Low Range 0 to ±2kV / inch

High Range 0 to ±20 kV / inch

Measurement Accuracy

Voltage Monitor Output Better than ±5% of reading,

10mV

Voltage Display Better than ±5% of reading,

±2 counts

Measurement Stability ±10 counts

Voltage Monitor

Output 2 volts output at full scale

Ratio

Low Range 1/1000 of the measured

electrostatic eld

High Range 1/10000 of the measured

electrostatic eld

Front Panel Meter

Voltage Display 3-1/2 digit LED display

Range

Low 0 to ±1.999 kV / inch

High 0 to ±19.99 kV / inch

Display Resolution

Low Range 1 V / inch

High Range 10 V / inch

Sampling Rate 3 readings per second

Features

Automatic Shuto󰀨 Unit will shut o󰀨 after 20

minutes from last activity

Ranging System LED distance indicator;

aligned targets indicate one
(1) inch

Range / Zero Switch LED distance indicator.

Resets the instrument to zero

and selects the measurement
range.

Low Battery Indicator An LCD display message

indicates when the battery is
low

Hold Switch Retains the LCD display

reading when depressed

DESCO EAST - One Colgate Way, Canton, MA 02021-1407 • [phone] • Website: Desco.com

DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 • [phone]

TB-3041 Page 5 of 6

© 2018 DESCO INDUSTRIES, INC.

Employee Owned

General

Dimensions 0.9" H x 2.8" W x 4.9"L

(24 mm x 70 mm x 126 mm)

Weight 4.9 oz. (140 g) with battery

Voltage Monitor
Connection

2.5 mm jack (3/32")
monophone

Tip Signal

Sleeve Ground

Operating Conditions

Temperature 50 to 86ºF (10 to 30ºC)

Relative Humidity To 80%, non-condensing

Altitude To 2000 m

Certications CE

Power Requirements

Power One (1) 9-volt alkaline battery

Operating Time Greater than 50 hours,

with a new battery at 21ºC
continuous

Power Switch A membrane switch that

is designed to prevent
accidental turn on. Powers

the instrument on and o󰀨.

Limited Warranty, Warranty Exclusions, Limit
of Liability and RMA Request Instructions

See the Desco Warranty -

Desco.com/Limited-Warranty.aspx

IONIZATION TEST KIT

Charge Plate Assembly Aluminum bracket, bare

aluminum plate and teon

spacers isolate plate from
bracket

Voltage Output 1/1,000 of measured voltage

@ low range
1/10,000 of measured
voltage @ high range

Charge Plate Area 2.95" W x 1.18" L

(7.5 x 3.0 cm)

Charge Plate Assembly

2.4 oz. (68 g)

Weight

Charger Dimensions 1.1" H x 2.6" W x 4.5" L

(2.8 x 6.6 x 11.4 cm)

Charger Weight 5 oz. (140 g) with battery

Charger Power

One 9-volt alkaline battery

Requirements

Charger Output (using

1.1 kV minimum for ± voltage
Static Field Meter with
charge plate)

Certications CE

DESCO EAST - One Colgate Way, Canton, MA 02021-1407 • [phone] • Website: Desco.com

DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 • [phone]

TB-3041 Page 6 of 6

© 2018 DESCO INDUSTRIES, INC.

Employee Owned