Fluke 5128A User guide

5128A

RHapid-Cal Humidity Generator

December 2016

© 2016 Fluke Corporation. All rights reserved. Specifications are subject to change without notice.
All product names are trademarks of their respective companies.

Operators Manual

LIMITED WARRANTY AND LIMITATION OF LIABILITY

Each Fluke product is warranted to be free from defects in material and workmanship under normal use and
service. The warranty period is one year and begins on the date of shipment. Parts, product repairs, and
services are warranted for 90 days. This warranty extends only to the original buyer or end-user customer of
a Fluke authorized reseller, and does not apply to fuses, disposable batteries, or to any product which, in
Fluke's opinion, has been misused, altered, neglected, contaminated, or damaged by accident or abnormal
conditions of operation or handling. Fluke warrants that software will operate substantially in accordance
with its functional specifications for 90 days and that it has been properly recorded on non-defective media.
Fluke does not warrant that software will be error free or operate without interruption.

Fluke authorized resellers shall extend this warranty on new and unused products to end-user customers
only but have no authority to extend a greater or different warranty on behalf of Fluke. Warranty support is
available only if product is purchased through a Fluke authorized sales outlet or Buyer has paid the
applicable international price. Fluke reserves the right to invoice Buyer for importation costs of
repair/replacement parts when product purchased in one country is submitted for repair in another country.

Fluke's warranty obligation is limited, at Fluke's option, to refund of the purchase price, free of charge repair,
or replacement of a defective product which is returned to a Fluke authorized service center within the
warranty period.

To obtain warranty service, contact your nearest Fluke authorized service center to obtain return
authorization information, then send the product to that service center, with a description of the difficulty,
postage and insurance prepaid (FOB Destination). Fluke assumes no risk for damage in transit. Following
warranty repair, the product will be returned to Buyer, transportation prepaid (FOB Destination). If Fluke
determines that failure was caused by neglect, misuse, contamination, alteration, accident, or abnormal
condition of operation or handling, including overvoltage failures caused by use outside the product’s
specified rating, or normal wear and tear of mechanical components, Fluke will provide an estimate of repair
costs and obtain authorization before commencing the work. Following repair, the product will be returned to
the Buyer transportation prepaid and the Buyer will be billed for the repair and return transportation charges
(FOB Shipping Point).

THIS WARRANTY IS BUYER'S SOLE AND EXCLUSIVE REMEDY AND IS IN LIEU OF ALL OTHER
WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY IMPLIED WARRANTY
OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. FLUKE SHALL NOT BE LIABLE
FOR ANY SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES OR LOSSES,
INCLUDING LOSS OF DATA, ARISING FROM ANY CAUSE OR THEORY.

Since some countries or states do not allow limitation of the term of an implied warranty, or exclusion or
limitation of incidental or consequential damages, the limitations and exclusions of this warranty may not
apply to every buyer. If any provision of this Warranty is held invalid or unenforceable by a court or other
decision-maker of competent jurisdiction, such holding will not affect the validity or enforceability of any other
provision.

Fluke Corporation
P.O. Box 9090
Everett, WA 98206-9090
U.S.A.

Fluke Europe B.V.
P.O. Box 1186
5602 BD Eindhoven
The Netherlands

11/99

Table of Contents

Title Page

Introduction ............................................................................................ 1

Contact Fluke Calibration ...................................................................... 2

Safety Information ................................................................................. 2

Symbols ................................................................................................. 4

Calibration and Repair Information ........................................................ 4

General Specifications .......................................................................... 5

Humidity and Temperature Chamber Technical Specifications ......... 6

Chamber Specifications ..................................................................... 6

Chamber Uniformity and Stability ...................................................... 6

Chamber Operational Range – Maximum % RH ........................... 7

Operational Specifications ................................................................. 7

Product Setup ........................................................................................ 8

Unpack and Inspect ........................................................................... 8

Product Placement ............................................................................ 8

Fill the Product with Distilled Water ................................................... 9

Mains Voltage .................................................................................... 10

The Product ........................................................................................... 12

Startup and Main Screen ................................................................... 15

Maintenance Screens ........................................................................ 15

Probe Calibrate Screen ..................................................................... 16

Probe Calibrate Screen ..................................................................... 16

BIT Humidity Gen Screen .................................................................. 16

Error Code Screen ............................................................................. 16

Firmware Version Screen .................................................................. 16

Operation ............................................................................................... 18

Chamber Door Use ............................................................................ 18

Door Styles ........................................................................................ 19

Turn On the Product .......................................................................... 19

Turn the Product Off .......................................................................... 20

Mixing Insert ...................................................................................... 20

Initial Warmup Period ........................................................................ 20

Set Temperature and Humidity .......................................................... 20

Condensation Prevention .................................................................. 21

Calibrate UUTs ...................................................................................... 22

Recommended Calibration Sequences ............................................. 22

Remove Condensation ...................................................................... 22

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Insert the UUT ................................................................................... 23

Stabilize the Chamber and UUT ........................................................ 24

Data Logger Calibration ..................................................................... 24

External Reference Probe Use .......................................................... 25

Sample In/Out Ports .......................................................................... 25

Temperature Extremes ...................................................................... 25

Remote Operation ................................................................................. 26

Set Up ................................................................................................ 26

Remote Commands ........................................................................... 26

Transport the Product ............................................................................ 27

Ship the Product .................................................................................... 27

Maintenance .......................................................................................... 27

Clean the Exterior .............................................................................. 27

Desiccant Replacement ..................................................................... 28

Water Level ....................................................................................... 29

Fuse Replacement ............................................................................ 29

Calibration ............................................................................................. 32

Calibration Principle ........................................................................... 32

Environmental Conditions .................................................................. 32

Equipment Setup ............................................................................... 32

Using a Chilled Mirror Probe ............................................................. 33

As Found Data Collection .................................................................. 36

Load Temperature and Humidity Offsets into the Product ................ 37

As Left Data Collection ...................................................................... 37

Temperature Uniformity Verification .................................................. 38

Error Messages ..................................................................................... 39

Error Codes ........................................................................................... 40

User-Replaceable Parts and Accessories ............................................. 41

ii

Introduction

The Fluke Calibration 5128A RHapid-Cal Humidity Generator (the Product) is a
precision-controlled humidity generator that produces a precise test environment
to calibrate humidity sensors. Use the front-panel to control the current
temperature and humidity in the chamber.

The Product:

• Controls and maintains the relative humidity and temperature in the chamber
to within a resolution of 0.1 % RH and 0.1 °C respectively.

• Has extremely fast response times for changes in humidity and temperature,
with ramp times as fast as 10 % RH/minute and 10 °C/minute.

• Has different door styles to accommodate a variety of humidity sensors.

• Features a simple front-panel user interface and USB Type-B connector for

remote operation.

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Operators Manual

Contact Fluke Calibration

To contact Fluke Calibration, call one of the following telephone numbers:

• Technical Support USA: 1-877-355-3225

• Calibration/Repair USA: 1-877-355-3225

• Canada: 1-800-36-FLUKE (1-800-363-5853)

• Europe: [phone]

• Japan: [phone]

• Singapore: [phone]

• China: [phone]

• Brazil: [phone]

• Anywhere in the world: [phone]

To see product information or download manuals and the latest manual
supplements, visit Fluke Calibration’s website at www.flukecal.com.

To register your product, visit http://flukecal.com/register-product.

Safety Information

A Warning identifies conditions and procedures that are dangerous to the user.
A Caution identifies conditions and procedures that can cause damage to the
Product or the equipment under test.

To prevent possible electrical shock, fire or personal injury:

• Read all safety information before you use the Product.

• Carefully read all instructions.

• Do not use the Product around explosive gas, vapor, or in

damp or wet environments.

• Use this Product indoors only.

• Do not tilt the Product with water in the reservoir. Product

must be installed on a flat stable horizontal surface.

Warning

2

RHapid-Cal Humidity Generator

Safety Information

• Use only the mains power cord and connector approved for

the voltage and plug configuration in your country and rated
for the Product.

• Replace the mains power cord if the insulation is damaged

or if the insulation shows signs of wear.

• Make sure the ground conductor in the mains power cord is

connected to a protective earth ground. Disruption of the
protective earth could put voltage on the chassis that could
cause death.

• Use the Product only as specified, or the protection

supplied by the Product can be compromised.

• Do not put the Product where access to the mains power

cord is blocked.

• Do not use the Product if it is damaged.

• Disable the Product if it is damaged.

• Do not use the Product if it operates incorrectly.

• Do not operate the Product with covers removed or the case

open. Hazardous voltage exposure is possible.

• Use only specified replacement parts.

• Use only specified replacement fuses.

• Have an approved technician repair the Product.

• Empty the reservoir before shipping the Product.

• Do not overfill the reservoir.

For safe operation and maintenance of the Product:

• Turn off the Product and remove the mains power cord.

Stop for 2 minutes to let the internal circuits discharge
before you open the fuse door or remove Product covers.

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Operators Manual

Symbols

Symbol Description

The symbols used in this manual and on the Product are shown in Table 1.

Table 1. Symbols

 WARNING. HAZARDOUS VOLTAGE. Risk of electric shock.
 WARNING. RISK OF DANGER.







Consult user documentation.

Certified by CSA Group to North American safety standards.
Conforms to European Union directives.

 Conforms to relevant Australian EMC standards.

 Fuse

 Conforms to relevant South Korean EMC Standards.

This product complies with the WEEE Directive marking requirements. The affixed label
indicates that you must not discard this electrical/electronic product in domestic household



Calibration and Repair Information

waste. Product Category: With reference to the equipment types in the WEEE Directive
Annex I, this product is classed as category 9 "Monitoring and Control Instrumentation"
product. Do not dispose of this product as unsorted municipal waste.

If calibration or repair is necessary during the warranty period, contact an
authorized Fluke Calibration Service Center to arrange for repair (see Contact
Fluke Calibration). Have the Product information ready such as the purchase
date and serial number to schedule the repair.

4

RHapid-Cal Humidity Generator

General Specifications

General Specifications

AC mains voltage................................................ 100 V to 240 V ±10 %, 47 to 63 Hz

Power consumption ............................................ 300 VA

Required test fluid ............................................... Distilled water

Warm-up period to meet specifications .............. Twice the time since last warmed up, to a maximum of 30 minutes

Internal humidifier warm-up period

(time for “HEATING” to go off) ............................ 30 minutes (Typical)

Mains Fuse Rating .............................................. F 4A 250 V (fast blow)

Operating ambient relative humidity range,

18 °C to 28 °C .................................................... Up to 80 % RH

Storage temperature and relative humidity ......... -20 °C to 50 °C, 0 % to 95 % RH, non-condensing

Transducer Power Output ................................... 12 V dc, 1 A maximum, fuse: F 1A 250V (fast blow)

Computer Interface… ......................................... USB

Safety .................................................................. IEC 61010-1, Installation Category II, Pollution degree 2,

Altitude ................................................................ 2000 m

Electromagnetic Compatibility (EMC)

International ........................................................ IEC 61326-1: Controlled Electromagnetic Environment

Class A: Equipment is suitable for use in all establishments other

Caution: This equipment is not intended for use in residential

Korea (KCC) ....................................................... Class A Equipment (Industrial, Broadcasting, & Communication

USA (FCC) .......................................................... 47 CFR 15 subpart B. This product is considered an exempt device per

Weight

Chassis only ....................................................... 15 kg (33 lbs)

Dimensions

Chassis ............................................................... 237 mm x 432 mm x 521 mm (9.3 in x 17 in x 20.5 in) (height x width x depth)

Overall Chamber Dimensions ............................. 200 mm (7.87 in) (depth) x 150 mm (5.90 in) (diameter)

Working Volume Dimensions .............................. 109 mm (4.3 in) (depth) x 125 mm (4.88 in) (diameter)

Temperature resolution:

Display ................................................................ 0.1 °C

USB data ............................................................ 0.1 °C

Humidity resolution:

Display ................................................................ 0.1 % RH

USB data ............................................................ 0.1 % RH

Dew Point

Resolution ........................................................... 0.1 °C (for indication only)

Indoor use only

CISPR 11: Group 1, Class A

Group 1: Equipment has intentionally generated and/or uses
conductively-coupled radio frequency energy that is necessary for
the internal function of the equipment itself.

than domestic and those directly connected to a low-voltage power
supply network that supplies buildings used for domestic purposes.
There may be potential difficulties in ensuring electromagnetic
compatibility in other environments due to conducted and radiated
disturbances.

environments and may not provide adequate protection to radio
reception in such environments.

Emissions that exceed the levels required by CISPR 11 can occur
when the equipment is connected to a test object.

Equipment)

Class A: Equipment meets requirements for industrial
electromagnetic wave equipment and the seller or user should take
notice of it. This equipment is intended for use in business
environments and not to be used in homes.

clause 15.103.

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5128A

Operators Manual

Humidity and Temperature Chamber Technical Specifications

The Product specifications describe the Absolute Instrumental Uncertainty of the Product. The Product specifications
include stability, ambient temperature, and humidity (within specified limits), linearity, line regulation, the reference
standard measurement uncertainty and long term stability of one year. The product specifications are provided at a 99 %,
k=2.58, normally distributed level of confidence.

Chamber Specifications

Note

The displayed dew point reading (DP) is calculated from the Product’s actual
temperature and %RH readings. It is calculated as a dew point (water vapor over
water) over the entire range, regardless if dew point is equal to or lower than 0
and at a nominal pressure of 101.325 kPa (1 atmosphere).

One Year, Ambient Temperature Range 23 °C ±3 °C

Chamber Temperature

Range

18 °C to 23 °C

>23 °C to 28 °C

[1] For ambient temperature range of 23°C ±5°C, multiply the specifications by 1.5.
[2] H

is the maximum humidity value at which the specification applies. See Chamber Operational Range below for H

max

Chamber Humidity Range Humidity Specification Temperature Specification

7 % to 80 % RH
>80 % to 95 % RH

7 % to 80 % RH
>80 % to H

max

[2]

% RH

±1.0 % RH
±1.25 % RH

±1.0 % RH
±1.25 % RH

Note

Specifications apply to the Working Volume shown in the Working Volume Template
found at the end of the Operators Manual, and are referenced to the “Actual”
reading on the Product display.

[1]

±0.2 °C
±0.2 °C

±0.2 °C
±0.2 °C

°

C,

.

max

Chamber Uniformity and Stability

[2]

[1]

Chamber
Humidity

Stability

[4]

[3]

Ambient Temperature Range: 23 °C ±3 °C

[2]

Chamber
Humidity

Uniformity

Chamber

Temperature

Chamber Humidity Range Chamber

Min % RH Max % RH

Temperature
Uniformity

See
Chamber

18 °C to 28 °C

7 % RH

Operational

±0.12 °C ±0.3 % RH ±0.1 % RH ±0.05 °C
Range
Below

The following specifications are typical for chamber conditions shown
5 °C to <18 °C
>28 °C to 30 °C
>30 °C to 35 °C
>35 °C to 40 °C
>40 °C to 50 °C

[1] For ambient temperature range of 23°C ±5°C, multiply the specifications by 1.5.
[2] Defined as the uniformity of the Working Volume.
[3] Defined as 1-sigma standard deviation of measurement readings over a 5-minute span.
[4] Chamber humidity uniformity is listed for mid-level humidity settings. Lower humidity settings will give better uniformity

while higher humidity settings will give worse uniformity.

15 % RH See
7 % RH
7 % RH
7 % RH

Chamber
Operational
Range
Below

7 % RH

±0.5 °C ±1.5 % RH ±0.5 % RH ±0.5 °C
±0.2 °C ±0.6 % RH ±0.3 % RH ±0.2 °C
±0.3 °C ±0.9 % RH ±0.4 % RH ±0.3 °C
±0.5 °C ±1.5 % RH ±0.5 % RH ±0.5 °C
±0.5 °C ±1.5 % RH ±0.5 % RH ±0.5 °C

Chamber

Temperature

Stability

[3]

6

RHapid-Cal Humidity Generator

General Specifications

Chamber Operational Range – Maximum % RH

The chamber has operational range limits based on temperature and humidity settings. The table below shows the
maximum % RH attainable at different temperatures.

Operational Specifications

Temperature rate of change – down .................. 1.5 °C/minute (Typical)

Temperature rate of change – up ....................... 10 °C/minute (Typical)

Humidity rate of change – down ......................... 5 % RH/minute (Typical)

Humidity rate of change – up .............................. 10 % RH/minute (Typical)

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Product Setup

Unpack and Inspect

Mains Power Cord 2-meter (6-foot) 1
5128A Safety Information (multi-language) 1
Report of Calibration and calibration label 1
Fill syringe with extension tube 1
Five-port square chamber door 1 (installed on the Product)

The subsequent sections explain Product inspection, placement, and setup.

Unpack the Product carefully and examine it for damage that could have
occurred during shipment. If there is shipping damage, contact Fluke Calibration
and the postal carrier immediately. Table 2 lists the equipment and the
accessories that come with the Product. Make sure that all the items are in the
box.

Table 2. Shipping Contents

Name Quantity

Port plug 5 (installed on each probe port)
Silicone Unit Under Test (UUT) grommets, ¼ in, ½ in, ¾ in, 1 in One of each size, 4 in total
Desiccant cartridge 1 (installed inside the Product)
USB Cable (Type A to Type B) 1

Product Placement

Put the Product on a clean, flat surface. For best results, choose a location
where room temperature changes are minimal. Make sure that there is at least
100 mm (4 in) clearance at the back of the Product for adequate air flow.

Caution

To avoid damage to the Product, only use it in its horizontal position. When
in use, if the Product is tilted more than 10 degrees from horizontal, water
can leak from the internal humidifier.

8

RHapid-Cal Humidity Generator

Product Setup

Fill the Product with Distilled Water

Before the Product is connected to mains power (see Mains Voltage), fill the
Product with 50 ml to 60 ml of clean, distilled water (see Figure 1).

1. Remove the fill cap from the front panel (see Front Panel).

2. Use the fill syringe and insert the extension tube over the fill inlet on the
Product.

3. Remove the plunger from the fill syringe and carefully pour water into the
syringe. Water can be forced into the Product with the plunger, or bring the
syringe to a higher level than the fill inlet and allow the water to flow into the
Product. Watch the water level indicator to gauge the fill level as the reservoir
is filled. The Product takes approximately two syringes of water.

Monitor the water level indicator to ensure the water level is between the Max
and Min lines.

Caution

To avoid damage to the Product, do not overfill the Product. If
the Product is overfilled, water may flood the chamber. Use the
drain port on the back of the Product to drain excess water. If
water is found within the chamber, it must be wiped dry with a
clean paper towel.

Figure 1. Fill the Water Level

ibw009.eps

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Mains Voltage

Warning

To prevent possible electrical shock, fire, or personal injury:

• Do not put the Product where access to the mains power

cord is blocked.

• Use only the mains power cord and connector approved for

the voltage and plug configuration in your country and rated
for the Product.

• Make sure the ground conductor in the mains power cord is

connected to a protective earth ground. Disruption of the
protective earth could put voltage on the chassis that could
cause death.

• Replace the mains power cord if the insulation is damaged

or if the insulation shows signs of wear.

The Product requires mains voltage that ranges from 100 V ac to 240 V ac with
frequencies from 50 Hz to 60 Hz.

The Product comes with the appropriate line power plug for the country of
purchase. See Table 3 for the mains line power plug types available from Fluke
Calibration.

10

RHapid-Cal Humidity Generator

Product Setup

Table 3. Available Mains Power Plug Types

LC-1

LC-6

LC-3

LC-4

LC-7 LC-42

LC-5

hwr039.eps

Type Fluke Calibration Option Number

North America LC-1
Universal Euro LC-3
United Kingdom LC-4
Switzerland LC-5
Australia LC-6
South Africa LC-7
Brazil LC-42

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The Product

This section describes front-panel operation, the working chamber, the display
and control panel, and the rear panel. See Tables 4, 5, 6, and 7.

Table 4. Front Panel

1 3

2 4 5

ibw001.eps

Item Name Description

 Display and Control Panel

Refer to Display and Control Panel for a full
description.

 Desiccant Cap Use to access the desiccant cartridge.
 Chamber Door Use to access the working chamber.

Draws and returns gas from the Product chamber.
Use to measure the dew point of the chamber with a

 Sample In/Out



Fill Inlet and Water Level
Indicator

chilled mirror instrument that has its own pump. The
Sample In/Out ports are the push-to-connect type,
and accept ¼ in OD tubing.

• Use the fill inlet to fill the internal humidifier with
distilled water.

• The water level indicator shows the relative
amount of water in the humidifier. This level is
best checked when the Product is in a standby
state (Chamber Control Standby is On), when the
Product has stabilized to its set point (for example
the pumps are mostly off), or with the Product off.

12

RHapid-Cal Humidity Generator

The Product

Table 5. Working Chamber

1

2

1

3

Item Name Description

Causes the air to circulate in a certain manner that gives better temperature
and humidity uniformity inside the insert. The volume inside the insert is the
working area where the Product guarantees its performance per the Product



Mixing Insert

specifications. See the end of this manual for a template that outlines the
working area. One of the three tabs on the outer part of the insert must be in
the 6 o’clock position as shown in the illustration ().This position ensures the
best temperature and humidity uniformity within the working area.

3

ibw023.eps



Outer
Chamber

The chamber where the mixing insert is placed. The UUT can be plac ed
directly into the outer chamber without the mixing Insert, but the temperature
and humidity will need to be monitored with an external reference probe.

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Table 6. Display and Control Panel

5128A

6

1

2

Item Name Description

Shows:

• Set points for temperature and humidity

 Display







NEXT
Button

Down
Button

Up
Button

• Actual temperature and humidity

• Calculated dew point

• Lower right corner: Display messages during operation at

first startup.

1. Push NEXT to toggle between the Temperature and Humidity Set
fields. The active set field blinks.

2. Push and hold down NEXT for 4 seconds to step to the Standby
screen.

3. When in the Standby screen, either down or up toggles the Standby
mode On or Off. Push and Hold EXIT down for 4 seconds to return to
the main screen.

Moves the temperature or humidity setting downward, depending on which
parameter blinks. A single button push increments the setting by one count.
Hold the button down to rapidly advance the setting.

Changes the temperature or humidity upward depending on which
parameter blinks. A single button push increments the setting by one count.
Hold the button down to rapidly advance the setting.

3 4 5

ibw002.eps

14

RHapid-Cal Humidity Generator

The Product

Table 6. Display and Control Panel (cont.)

Item Name Description





EXIT
Button

Status
Indicators

Hold down for 4 seconds (from any screen) to return to the main screen.

Remote: Indicates communication over the USB serial interface.
Check Desiccant: Indicates there may be issues with the dry gas sub-

system. Causes can be a saturated desiccant cartridge, a user setting that
takes the Product longer to transition than normal, condensation within the
chamber, and/or a leak in the system. See Troubleshooting for more details.

Check Water: Indicates there may be issues with the wet gas sub-system.
Causes can be a low water level, a user setting that takes the Product longer
to transition than normal, condensation within the chamber, and/or a leak in
the system. See Troubleshooting for more details.

Startup and Main Screen

When the Product is first activated, the display shows the Product model number
on the startup screen. The Product then changes to the main screen and shows
. This indicates that the internal humidifier is warming up to create
sufficient water vapor that will allow high-relative humidity value settings. The
Product will not control the chamber temperature or humidity when  is
on the main screen. To bypass this warmup period and control the chamber,
push EXIT once. he Product now controls the chamber. When the heating
process is bypassed, it may initially take longer to reach higher relative humidity
values. Once the Product automatically removes the message, the
setting time of higher relative humidity values is more consistent.

Maintenance Screens

Use the maintenance screens to calibrate the Product, troubleshoot the internal
humidifier, and obtain a list of error codes. To access the maintenance screens,
simultaneously hold NEXT and EXIT down. In 4 second intervals, the probe
offset screen appears, followed by the BIT humidity screen, error codes and
firmware version. To stop at any of these screens, release NEXT and EXIT when
the appropriate screen appears. For Product maintenance, see Maintenance.

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Probe Calibrate Screen

BIT Humidity Gen Screen

Error Code Screen

The probe calibrate screen shows the probe offsets for temperature and humidity
and is used in the Product-adjustment process. Use the probe calibrate screen to
load in a temperature offset and humidity offset to adjust the Product chamber
output. Probe offsets are entered as part of the routine calibration process.

An example of the calibration offset screen:



°
°


The BIT humidity gen screen contains parameters associated with the internal
humidity generator and is only used by trained service personnel. Push and hold
down EXIT to return to the main screen.

The error code screen is shown and errors that the Product detects are
presented. See Error Codes for a list of error codes. Push and hold EXIT to
return to the main screen.

Firmware Version Screen

Product firmware version details are shown. Push and hold EXIT to return to the
main screen.

16

RHapid-Cal Humidity Generator

The Product

Table 7. Rear Panel

1

2

F1A 250V

FUSE

LOHI

12 VDC

DRAIN

USB

10 9 7

3

458 6

Item Name Description

 Fan inlet/outlet holes Do not block the inlet/outlet holes.
 Fans The two fans provide internal cooling to the Product.

ibw003.eps



Power supply fan access
holes

Provides cooling for the internal power supply. Do not block
these holes and periodically vacuum to remove any dust.

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Item Name Function



 Power switch Turn on and off the Product.

Fuse Holder and Mains
Power Cord Receptacle

Table 7. Rear Panel (cont.)

Contains two mains fuses and the receptacle for the mains
power cord. Use an ac mains supply appropriate for the
voltage range and region of use. See Mains Voltage and
Maintenance.

 USB Type B connector

Use this connection to remotely control the operation of the
Product. Refer to Remote Operation.

 LO LO terminal for the 12 V dc output.
 Drain plug

 HI

Used to drain water from the Product. Drain water if
overfilled or for shipment.

HI terminal for the 12 V dc output to power up transmitters
and transducers.

 Fuse 12 V dc output fuse (F1A 250 V fuse).

Operation

The subsequent sections explain Product operation. Before Product use, see Fill
the Product with Distilled Water.

Chamber Door Use

Note

Before the Product is powered on, make sure that there is a
chamber door secured in place. Without a door in place the Product
can quickly lose water if the Product is not in the Standby state.

The Product ships with the square 5-port door. Other door styles are available as
accessories. See Figure 2 and see User-Replaceable Parts and Accessories.

18

Figure 2. Five Port Square Door

ibw011.eps

RHapid-Cal Humidity Generator

Operation

Door Styles

• (Standard) Square door with five ports, silicone gasket, center

tightening screw, and four fasteners (one at each corner)

To install and use this door, push the door into the chamber opening until it
stops. Then hand tighten the center screw to seal the round silicone gasket to
the chamber.The four corner screws (1/4 in x 20 threads) are used to
precisely locate the port locations and to further tighten the door against the
black outer seal on the outside of the chamber.

• (Accessory) Round door with five ports, silicone gasket, and center

tightening screw (accessory)

To install and use this door, hand tighten the center screw to seal the round
silicone gasket to the chamber. Loosen the center screw to remove the door
from the chamber opening. To re-insert the door, align the rear acrylic piece,
middle silicone gasket, and front acrylic piece and then place the assembly
onto the chamber opening. Hand tighten the center screw to provide a snug,
airtight seal. The UUT probes, and any external reference probe(s), are
inserted into one of the five ports by removing the cap and placing the UUT
through the cap and appropriate-sized silicone grommet and port opening.

• (Accessory) Clear square door with no ports, no silicone gasket, and

four fasteners (one at each corner)

To install and use this door, use the four corner screws (1/4 in x 20 threads)
to fasten the door in place and tighten the door against the black outer seal
on the outside of the chamber. Use this door to calibrate data loggers that are
placed into the chamber. Use this door in conjunction with a shelf inside the
chamber. See Data Logger Calibration.

To avoid measurement issues, do not open the chamber door when
the chamber temperature is below the ambient temperature. Water
vapor from the atmosphere will condense inside the chamber. If
condensation forms inside the chamber, shut the Product off and
remove the power cord. Thoroughly dry the chamber with a clean
paper towel before further use. See Remove Condensation.

Turn On the Product

To turn on the Product:

1. Push the “1” side of the power switch on the rear panel.

2. Monitor the startup screen for errors as the Product powers up. If an error
shows, see Troubleshooting and Error Code. Contact Fluke Calibration for
unresolved errors, see Contact Fluke Calibration.

3. Wait for to disappear from the main screen before the temperature
and humidity are set.

Note

19

5128A

Operators Manual

Turn the Product Off

Mixing Insert

Push the power switch on the rear panel to the “0” position to turn off the
Product.

If the chamber dew point is greater than the ambient temperature, to avoid
condensation, do not open the chamber door for 1 hour so that the chamber
comes to room temperature.

Do not turn off the Product when its actual humidity is >80 %. Doing so risks the
chance that condensation will form inside the chamber. When possible, turn the
Product to a lower humidity before it is powered off.

The mixing insert improves the temperature and humidity uniformity of the
Product. It contains the working area that has guaranteed performance. The
mixing insert can be removed to calibrate larger UUTs. In this case, an external
reference probe should be used to monitor actual temperature and humidity
conditions. Slide the mixing insert out of the chamber to remove it. To reinstall,
align the posts on the mixing insert against the chamber walls, and gently slide it
back into the rear of the chamber. One of the three tabs on the outer part of the
insert must be in the 6 o'clock position as shown in Table 5. This position
ensures the best temperature and humidity uniformity within the working area.

To check for water condensation, remove the mixing insert from the chamber and
then reinstall it.

Initial Warmup Period

The Product is a fast-response system able to change temperature as quickly as
10 °C per minute and 10 % RH per minute. However, the Product can have a
slower initial response after exposure to cold temperatures when transported or
long periods of being off. When cold, and upon initial power up, the Product
heats up the internal humidifier and creates necessary water vapor. When
sufficient water vapor is generated,  is removed from the main screen,
and the Product is ready for use.

Set Temperature and Humidity

To change the set point for temperature:

1. Push NEXT until the Temp number on the display blinks.

2. Push up or down to move the set point up or down. Hold up or down down
to quickly change the set point.

3. To change the set point for humidity, push NEXT until the RH number blinks.
Push up or down to increment the set point up or down. Hold up or down
down for a faster change in set point.

20

RHapid-Cal Humidity Generator

Operation

Condensation Prevention

The Product has a condensation-prevention feature that minimizes the possibility
of condensation when certain user settings are called for. At high humidities,
when the chamber dew point is within 2 °C of the actual chamber temperature, a
CAUTION message shows on the lower right hand corner of the display and the
controller slows the rate of temperature and humidity change. If the CAUTION
message shows, do not set temperatures significantly below the actual
temperature without first setting the humidity to a lower level.

For example, a UUT has verification points at 23 °C 90 % RH followed by 10 °C
90 % RH. The first set point, 23 °C and 90 % RH has a dew point of 21.3, within
2 °C of the actual temperature. When the chamber actual conditions reach this
set point, CAUTION shows on the display. Before setting the chamber to 10 °C,
set the humidity to about 1/2 the Actual (45 %). When that humidity is reached,
then set the Product to 10 °C 90 % RH.

Note

A better verification pattern to avoid condensation would be to set
the lower dew point condition first, in this case 10
followed by 23

°

C 90 % RH.

°

C 90 % RH

If condensation forms inside the chamber, the check desiccant or check water
indicator may be on, and/or the actual humidity is far off from the set humidity
after the typical stabilization time. See Remove Condensation.

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Operators Manual

Calibrate UUTs

Recommended Calibration Sequences

The subsequent sections explain how to do calibrations on humidity probes or
UUTs.

These recommendations ensure fast, repeatable calibrations of humidity
sensors:

1. Do lower-relative humidity calibrations first and ramp up to the higher­humidity levels on each subsequent calibration step.

2. Do lower-temperature calibration points first to minimize the probability of
water vapor condensing inside the chamber.

3. In general, best practice is to start at the lowest dew point and then move up
in dew point during a calibration procedure.

Note

When the dew point of the Product chamber is greater than the
ambient temperature, condensation can form on or near the
chamber door or on the UUT. If condensation forms anywhere in the
chamber, the relative humidity inside the chamber is unknown.
Condensation must always be removed from inside the chamber
before calibrations are performed. See Remove Condensation.

Remove Condensation

To remove condensation:

1. Turn off the Product, unplug the mains power cord, and remove the chamber
door.

2. Carefully inspect the mixing insert, chamber door, and UUT.

3. Remove the mixing insert to check the outer chamber for condensation.

4. Wipe off all condensation and moisture with a clean paper towel.

5. If condensation is present on the UUT, wipe the outer surfaces with a clean
paper towel. Do not touch the humidity sensing element.

6. Re-install the mixing insert, re-attach the door, plug in the mains power cord,
and turn on the Product. Heat the chamber to 40 °C and relative humidity to
10 % for approximately 10 minutes to ensure proper performance.

22

RHapid-Cal Humidity Generator

Calibrate UUTs

Insert the UUT

To make sure the UUT is inserted into the Product chamber correctly, use the
working volume template that is included at the end of this manual, see
Figure 11.

Use one of the probe ports on the chamber door to insert the UUT into the
chamber:

1. Make a copy of this figure and physically place it on top of the Product over
the chamber. Use the template to know how far to insert the UUT. See
Figure 3.

2. Unscrew the cap on the probe port and remove the plug.

3. Place the UUT probe through the cap and an appropriately-sized silicone
grommet.

4. Put the UUT probe inside the port opening. Ensure the UUT sensor is inside
the working volume of the chamber. The working volume is outlined in
Figure 11, and has a depth of 76 mm to 152 mm (3 in to 6 in) from the inner
door face.

5. Hand tighten the cap around the UUT to give an airtight seal. If necessary,
add sealant material around the UUT probe. Parafilm, Scotch™ Removable
Adhesive Putty, or similar materials work well.

For probes that are too short to fit in the working volume, use an extension cable
for the probe if available. The port cap and appropriate-sized silicone grommet
should be hand tightened around the cable with the UUT probe attached to the
cable on the inside of the door.

4.30

0

0

.

1

WORKI

C

M

HA

INI

MU

MB

M

E

R

C

.88

4

OV

ER

M

A
X

I

M

U
M

NG AR

EA

Figure 3. Use the Working Volume Template

ibw022.eps

23

5128A

Operators Manual

Stabilize the Chamber and UUT

Data Logger Calibration

For short probes without an available cable, insert the probe into the door as far
as possible and do calibrations at or near ambient temperature. This eliminates
temperature gradients between the UUT and the chamber. Under these
conditions, where the UUT probe is not fully immersed in the working volume, an
external reference probe that is inserted at the same depth should be used to
ensure the best calibration.

The Product response time is normally much faster than that of the UUT, with
typical stabilization times <5 minutes between typical UUT verification points.
However, to ensure that the UUT temperature and humidity is at equilibrium with
the chamber conditions, allow for stabilization times of at least 15 minutes
between set points. Longer stabilization times may be necessary if the initial UUT
temperature is significantly different than the chamber temperature and if the
chamber is set to extreme humidity and temperature set points. Monitor the
actual temperature and humidity points as shown on the Product display.
Chamber stabilization is typically reached when the actual temperature is within

0.1 °C of the set temperature, and the actual humidity is within 0.2 % of the set

humidity.

To calibrate Data Loggers:

1. Place them directly into the calibration area of the chamber and use the clear
glass door and the shelf accessory. See Figure 4 for approximate placement.

Figure 4. Data Logger Placement

ibw025.eps

2. Put the UUT into its data logging mode, and then set and record the actual
calibrator temperature and humidity at known points in time.

24

3. Compare the UUT logged data against the actual Product temperature and
humidity settings.

For data loggers that are too large to fit inside the mixing

insert, but fit inside the outer chamber, the larger shelf can be used to hold
the UUT. Use an external reference probe to monitor the conditions of the
Product.

RHapid-Cal Humidity Generator

Calibrate UUTs

External Reference Probe Use

Use an external reference probe inserted into one of the chamber door ports to
perform calibrations tied to the uncertainty of the external probe. This is
necessary when the mixing insert is removed to accommodate larger UUTs, or to
obtain lower uncertainties in the calibration. A membrane-type sensor or chilled
mirror can be used for an external reference. The air flow within the chamber
should be sufficient for most remote chilled mirror probes such that an external
pump is not necessary. Match the depth of the external reference to the UUT
probe depth whenever possible.

Sample In/Out Ports

The humidity within the working chamber can be measured with a chilled mirror
that does not have a remote probe by drawing gas samples out of the chamber
using the Sample In/Out ports at the front of the Product. Use an external pump
capable of generating a flow of 0.5 liters per minute. The gas sample dew point
must be below the ambient temperature to avoid condensation on the Sample
In/Out port lines, otherwise the lines must be heated to 5 °C above the chamber
temperature. Fluke Calibration recommends that the gas sample is returned back
to the Product through the Sample In port.

Measure the temperature within the chamber and the dew point measurement
from the chilled mirror to determine the relative humidity inside the Product
chamber. For the best performance, use stainless steel or PTFE tubing for all
connections to the Sample In/Out ports.

Temperature Extremes

The Product has guaranteed specifications using its internal reference for
chamber temperatures from 18 °C to 28 °C, 7 % to 95 % RH (see Specifications
for exact points). Chamber temperatures outside of this range can be generated,
but an external reference probe should be used.

When a UUT or reference probe is inserted through the door, stem conduction
should be considered at the extremes of the Product generating range (for
example, chamber conditions below 18 °C or above 28 °C). At these extremes,
condensation may form at cold spots in the system. To avoid condensation,
place the entire UUT measurement head inside the chamber with an extension
cable. Place insulation around the door to help prevent condensation.

25

5128A

Operators Manual

Remote Operation

Set Up

Remote Commands

For remote operation of the Product, send ASCII commands through the USB
serial interface. The USB interface appears as a virtual COM port when
connected to a Windows PC.

Connect a USB A to B cable between the Product and PC. If this is the first time
the PC has been connected to the Product, you may be prompted to download
and install the drivers for the interface. The drivers are normally part of the
Windows operating system. Windows detects the interface as a virtual COM port.
If Windows is unable to find the driver, contact Fluke Calibration for technical
support. Refer to Contact Fluke Calibration.

The default settings on the Product are 9600 baud, 8 data bits, 1 stop bit, no
parity or flow control. These settings cannot be changed.

To use the USB interface, use the remote commands in Table 8 to communicate
with the Product. When communication is active, the Remote indicator on the
front panel is lit.

Table 8. Remote Commands

Command Read/Write Function

BOOT Write Resets the Product.
HELP Read Returns the list of remote commands available.

ID Reads

HOFFSET Read

HOFFSET x.x Write

TOFFSET Read

TOFFSET x.x Write
HREAD Read Returns the actual chamber humidity.

TREAD Read Returns the actual chamber temperature.
DPREAD Read Returns the calculated chamber dew point temperature.
HSET Read Returns the humidity set point.
TSET Read Returns the temperature set point.
HSET xx.x Write Sets the humidity set point to xx.x (% RH).
TSET xx.x Write Sets the temperature set point to xx.x (in deg C).
STANDBY Read Returns the standby state, either ON or OFF.
STANDBY ON Write Puts the Product into its Standby state.
STANDBY OFF Write Puts the Product into its normal operating state.

WARMUP Read

Returns “Fluke 5128A”, serial number and firmware
revision.

Returns the value of the humidity offset stored within the
Product.

Sets the humidity offset used in the Product as part of the
calibration process (% RH).

Returns the value of the temperature offset stored within
the Product (in °C) .

Sets the temperature offset used in the Product as part of
the calibration process.

Returns status of warmup indication. "On" means that
"Heating" is still on.

26

RHapid-Cal Humidity Generator

Transport the Product

Transport the Product

Ensure that the water level is below the MAX indicator on the front panel when
transporting the Product on a cart or in a vehicle. Excess water may flow into the
Product otherwise. Always transport the product in its horizontal position.

Ship the Product

Fluke Calibration recommends that the Product be drained of water before
shipping. To do so, unfasten the drain screw cap on the rear of the Product, and
drain the water by slightly tilting the Product. When shipping the Product, use the
original carton and packing material or Fluke Calibration case accessory part
number 4791304.

Maintenance

This section explains routine operator maintenance necessary to keep the
Product in optimal condition.

Clean the Exterior

To clean the Product, wipe it with a cloth that is lightly dampened with water or
mild detergent. Do not use aromatic hydrocarbons, chlorinated solvents, or
methanol-based fluids. To clean the display, use a soft cloth lightly dampened
with alcohol.

Caution

Do not use aromatic hydrocarbons or chlorinated solvents for
cleaning. They can damage the plastic materials used in the
Product.

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5128A

Operators Manual

Desiccant Replacement

The Product uses a mixed-flow method to generate relative humidity. A desiccant
cartridge provides a source of low humidity and an internal humidifier generates
high humidity. Check the desiccant cartridge when the Check Desiccant
indicator is lit on the front panel or the display shows . The normally­blue desiccant material is pink when it becomes saturated. When the entire
normally-blue desiccant material is pink, the cartridge should be replaced. See
Display and Control Panel.

To change the desiccant cartridge (see Figure 5):

1. Turn the Product off.

2. Turn the front panel cap ¼ turn counter-clockwise and remove the cap.

3. Loosen the rear seal of the desiccant by gently nudging the front of the
desiccant in various directions (up/down, left/right).

4. Pull the spent cartridge out of the Product and insert a new cartridge.

Additional desiccant cartridges are available from Fluke Calibration.

28

3

2

Figure 5. Change the Desiccant Cartridge

ibw026.eps

RHapid-Cal Humidity Generator

Maintenance

Water Level

Use the Product only when the water level is between Max and Min on the front­panel indicator as viewed with the Product off or in Standby state. Check the
water level when the Check Water indicator is lit on the front panel or the display
shows . There are multiple reasons for Check Water and/or
 to appear. See Troubleshooting for more details. Do not add more
water if the level is between Max and Min, as this overfills the Product. Use only
clean, distilled water to fill the reservoir. Use the drain plug at the rear of the
product to drain excess water from the Product. See Display and Control Panel.

Warning

To prevent possible electrical shock, fire or personal injury, do
not overfill the reservoir.

Fuse Replacement

The Product has mains fuses located in the mains input assembly. The fuse­rating label above the mains input assembly shows the correct replacement fuse
ratings for each operating voltage.

Warning

To prevent possible electrical shock, fire, or personal injury:

• Turn the Product off and remove the mains power cord.

Stop for two minutes to let the power assemblies discharge
before you open the fuse door.

• Use only specified replacement fuses, see Table 9.

Table 9. Replacement Mains Fuses

Line Voltage Fuse Type

 100 V to 120 V,  220 V to 240 V 5 X 20 mm 4 Amp Fast Blow (F4A 250V)

29

5128A

Operators Manual

To replace the mains fuse, refer to Figure 6:

1. Disconnect the mains power cord.

2. With a standard screwdriver, release the fuse holder door .

3. Pull out the fuse holder .

4. If necessary, replace the fuse .

5. Reinsert the fuse holder.

6. Close the fuse holder door.

1

2

Figure 6. Replace the Mains Fuses

3

ibw007.eps

30

RHapid-Cal Humidity Generator

Maintenance

The Product has a fuse for the 12 V dc transducer power output located in the
rear panel. Replace only with a 1 A Fast Blow fuse (F1A 250V 5x20mm). To
change the fuse, see Figure 7.

1

A

MP M

AX

+

12VDC

G

ND

DRAIN PLUG

F

U

S

E

ibw024.eps

Figure 7. Replace the 12 V Fuse

31

5128A

Operators Manual

Calibration

Calibration Principle

This section contains calibration procedures for the Product.

To calibrate the Product, the chamber is measured at a variety of temperatures
and relative humidity levels using a 70 % guardband to account for measurement
uncertainty. Temperature and humidity offsets are stored in the Product if
readings are found to be outside of the allowed tolerances.

The calibration settings order shown in Table 11 is optimized to give the fastest
Product stabilization times, and also to minimize the chance of condensation
during the calibration process.

Required calibration equipment is listed in Table 10.

Table 10. Calibration Equipment

Classification

Chilled mirror
hygrometer

Readout

Thermistor

Thermistor
probe fixture

Calculator

Minimum Use

Specification

0.1 °C dew point
uncertainty

0.006 °C @ 25 °C
thermistor uncertainty

0.01 °C calibration
uncertainty

Positions four of the
thermistor probes in a
square pattern at the rear
of the working area, and
the other four thermistors
in a square pattern in the
front of the working area

Relative humidity
calculator

Environmental Conditions

Laboratory environmental conditions required to complete this procedure:

Recommended Equipment

Michell Instruments S8000 Remote, or RH
Systems 473 with RP2 probe

Fluke 1586A Super-DAQ Precision Temperature
Scanner with DAQ-STAQ multiplexer

Fluke 5611T 8 probes are required

Custom wire jig

Thunder Scientific Humicalc®, Michell
Instruments Humidity Calculator, Vaisala
Humidity Calculator

32

• Temperature range: 23 °C ±3 °C

• Relative humidity: below 60 %

Equipment Setup

Attach the chilled mirror probe and thermistor probes as shown in Figure 9.
Connect the thermistor probe to the thermistor readout and the chilled mirror
probe to the chilled mirror instrument.

RHapid-Cal Humidity Generator

Calibration

Using a Chilled Mirror Probe

There are different ways to use a chilled mirror with the Product. The subsequent
sections outline several of them:

• You can draw a gas sample from the chamber as shown in Figure 8. The
tube to extract the sample is inserted into one of the ports. The chilled mirror
sensor needs its own pump to draw the sample from the chamber.
Experiment with the pump speed to draw enough gas for the chilled mirror to
work, but not so much that the Product performance is adversely affected. A
flow range of 0.1 liters to 0.5 liters per minute is usually adequate. Use PTFE
or stainless tubing for best results.

Caution

When drawing gas out of the chamber in this method, the dew
point of the gas must be lower than ambient temperature,
otherwise a heated tube must be used to prevent the formation
of condensation in the tube.

Figure 8. Chilled Mirror with Pump Connections

ibw013.eps

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5128A

Operators Manual

• If the chilled mirror has a remote sensing head that fits into one of the door
ports, insert the remote head into the door as shown in Figure 9. Ensure that
the remote head sensor is inserted into the working volume of the chamber.
There is sufficient gas flow within the chamber such that an external pump is
normally not needed in this situation.

Figure 9. Chilled Mirror Probe Inserted Directly into the Door.

ibw012.eps

34

RHapid-Cal Humidity Generator

Calibration

• A gas sample from the Sample Out port can be drawn with a chilled mirror
that has a pump, returning the gas into the Sample In port. A flow rate of

0.1 liters to 0.5 liters per minute is usually adequate. Ensure the chosen flow
rate does not cause excessive chamber temperature non-uniformity. Use
PTFE or stainless tubing for best results. See Figure 10.

Caution

When drawing gas out of the chamber in this method, the dew
point of the gas must be lower than ambient temperature,
otherwise heated tubes must be used to prevent the formation
of condensation in the tube.

Figure 10. Connections

ibw021.eps

35

5128A

T

T

Operators Manual

As Found Data Collection

For each step in Table 11:

1. Set the Product to the calibration set point shown in Table 11. Allow
35 minutes for stabilization.

2. Take the dew point measurement with the chilled mirror.

3. Take the temperature measurement with the 5611T probes. Calculate the
average of the 8 temperature measurements for each step and enter that as
each of the Temperature Readings in Table 11.

4. Use a relative humidity calculator to determine the relative humidity for that
test point.

Table 11. Calibration Steps

Step

1 18 °C 7 % 17.86 °C 18.14 °C 6.3 % 7.7 %
2 18 °C 20 % 17.86 °C 18.14 °C 19.3 % 20.7 %
3 23 °C 20 % 22.86 °C 23.14 °C 19.3 % 20.7 %
4 28 °C 20 % 27.86 °C 28.14 °C 19.3 % 20.7 %
5 23 °C 35 % 22.86 °C 23.14 °C 34.3 % 35.7 %
6 18 °C 45 % 17.86 °C 18.14 °C 44.3 % 45.7 %
7 23 °C 45 % 22.86 °C 23.14 °C 44.3 % 45.7 %
8 28 °C 45 % 27.86 °C 28.14 °C 44.3 % 45.7 %
9 18 °C 80 % 17.86 °C 18.14 °C 79.3 % 80.7 %
10 23 °C 80 % 22.86 °C 23.14 °C 79.3 % 80.7 %
11 23 °C 80 % 27.86 °C 28.14 °C 79.3 % 80.7 %
12 23 °C 95 % 22.86 °C 23.14 °C 94.13 % 95.88 %
13 28 °C 70 % 22.86 °C 23.14 °C 69.3 % 70.7 %

Temperature

Set Point

Humidity
Set Point

Dew Point

Reading

Temperature

Reading

Calculated

RH

Low T

Tolerance

High T

Tolerance

Low RH

olerance

High RH

olerance

36

RHapid-Cal Humidity Generator

Calibration

Load Temperature and Humidity Offsets into the Product

If there are any observed errors in the As Found data that are greater than 70 %
of tolerance, temperature and humidity offsets can be entered into the Product. If
the subsequent procedure cannot bring the Product into tolerance, contact Fluke
Calibration.

To load offsets into the Product:

1. Record the As Found temperature and relative humidity offset values that are
entered into the Product.

2. Record the Product displayed Actual temperature at the set point of 23 °C,
35 %. Calculate the difference from reference temperature (actual
temperature at 23 °C) as “A” (A = DUT_Actual_T - Ref_T).

3. Record the Product displayed Actual temperature at the set point of 23 °C,
80 %. Calculate the difference from the reference temperature as “B”.

4. Calculate T_Error with: T_Average_Error = (A + B) / 2.

5. Calculate the new temperature offset with:
T_Offset_New = T_Offset_As_Found - T_Average_Error

6. Record the Product displayed Actual relative humidity at the set point of
23 °C, 35 %. Calculate the difference from the reference as “C” (C =
DUT_Actual_RH - Ref_RH).

7. Record the Product displayed Actual relative humidity at the set point of
23 °C, 80 %. Calculate the difference as “D”.

8. Calculate RH_Error with: RH_Average_Error = (C + D) / 2.

9. Calculate the new relative humidity offset with: RH_Offset_New =
RH_Offset_As_Found - RH_Average_Error.

10. To update the temperature and relative humidity offsets, access the Probe
Calibration Screen. Simultaneously hold NEXT and EXIT down for 4 seconds.
The offset that can be changed in this screen is blinking. Push up and down
to change the value of the blinking characters and store the new offset. Push
NEXT to move to the other offset field. Push up and down to change the
value of the blinking characters and store the new offset for that field.

11. Push and hold EXIT for 4 seconds to return to the main screen.

As Left Data Collection

If it is not necessary to enter new temperature and humidity offsets into the UUT,
the calibration is complete. If temperature and humidity offsets were changed per
the Load Temperature and Humidity Offsets into the Product section, then use
the steps in the As Found Data Collection section to take As Left data.

37

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Operators Manual

Temperature Uniformity Verification

Troubleshooting

The temperature uniformity verification uses the temperature data collected when
measuring each of the set points in Table 11. It compares each of the 8
temperature probes against the average of the 8 probes. Temperature uniformity
at each of the 8 measurement points is defined as absolute maximum of Tx –
T_average, where x refers to one of the 8 probes. Each of the 8 probes must
read within ±0.12 °C of T_average.

See Table 12 for possible causes and solutions to common problems.

Table 12. Troubleshooting

Problem Possible Cause Solution

Check Desiccant

indicator is lit with
a non-saturated
desiccant
cartridge. Display
has the message
LO RH ERR.

Check Water

indicator is lit with
the water at the
proper level.
Display has the
message HI RH
ERR.

Product setting is at a temperature
and/or humidity extreme relative to
the prior setting such that transition
times are longer than normal.

There may be condensation in the
chamber.

There is a leak in the system.

Product setting is at a temperature
and/or humidity extreme relative to
the prior setting such that transition
times are longer than normal.

There may be condensation in the
chamber.

There is a leak in the system.

Monitor the Product to see that the
actual humidity is still dropping. If it is,
the Check Desiccant indictor will
eventually turn off unless the Product
setting is beyond its specifications.

Monitor the Product to see that the
actual humidity is still dropping. If it is
not, there is likely condensation in the
chamber. Turn the Product off and
check for condensation. See Remove
Condensation.

Check that the door is properly seated,
and tightened against the Product front
panel. Check that all ports are sealed
properly.

Monitor the Product to see that the
actual humidity is still moving up. If it is,
the Check Water indictor will
eventually turn off unless the Product
setting is beyond its specifications.

Monitor the Product to see that the
actual humidity is still moving up. If it is
not, there is likely condensation in the
chamber. Turn the Product off and
check for condensation. See Remove
Condensation.

Check that the door is properly seated,
and tightened against the Product front
panel. Check that all ports are sealed
properly.

38

Actual humidity is
much higher than
the set point. For
example, the set
point is 23 °C,
45 % RH and the
Actual is 23 °C
with RH staying
close to 80 %.

Water has condensed inside the
chamber.

Shut off power. Remove the door and
inner chamber (mixing insert) and look
for water inside the outer chamber,
mixing insert, door, and UUT. Wipe dry
with a clean paper towel and reinstall
the inner chamber and door.

RHapid-Cal Humidity Generator

Error Messages

Problem Possible Cause Solution

Desiccant cartridge needs to be
replaced.

Door not properly sealed, causing a

Cannot reach the
very low humidity
levels, for
example 7 %.
Check Desiccant
indicator on front
panel may be on.

“” stays
on longer than
usual at power­up.

leak.

UUTs are not adequately sealed
within its port.

If using a chilled mirror with an
external pump and not returning the
gas sample back to the Product,
you may be drawing too much gas
from the Product.

The internal humidity generator may
be overfilled.

Error Messages

The product has Error Messages that show information during general use of the
Product. Error Messages are not necessarily related to the Error Codes that
follow this section. The latter indicates an internal failure that requires servicing
of the Product. Error messages are shown in Table 13.

Shut off power, open the desiccant
cartridge. Inspect. Replace if the
normally blue cartridge material is pink.

Tighten door.

Check to see that the appropriate
grommet is used, and/or add sealant
material around the UUT probe.
Parafilm, Scotch Removable Adhesive
Putty or like material works well.

Turn down the pump setting.

Shut off power. Drain excess water
using the drain outlet on the back of the
Product until water level is between
Max and Min with the Product in
Standby or turned off.

Table 13. Error Messages

Error Message Description

At high humidity settings, when the actual chamber temperature is within 2 °C of

Caution

HI RH ERR

LO RH ERR

the actual chamber dew point, CAUTION appears to warn of possible
condensation conditions if subsequent settings are lower in temperature.

Usually associated with the Check Water indicator. Causes include a low water
and condensation in the system. See Troubleshooting for more details.

Usually associated with the Check Desiccant indicator. Causes include a saturated
desiccant and condensation within the system. See Troubleshooting for more
details.

39

5128A

Operators Manual

Error Codes

“No Analog Detected” Internal Hardware fault.
“Internal Probe Fail” Internal hardware fault.

“No Peltier Temp” Internal over temperature probe fault, fans will run continuously.

“No HumGen Temp” Internal temperature probe failure.

“Peltier High Limit” Internal cooling sensor is above limit.

If the Product detects an internal failure, the display shows “”. To
determine the specific fault, push and hold down NEXT and EXIT simultaneously
until the error code screen appears. The list of error codes is in Table 14.

Table 14. Error Codes

Error Code Description

“HumGen Low Limit”

“HumGen High Limit”

“EEPROM Cfg Reset” Unit has reset its configuration to factory default, review settings.

“EEPROM Cal Reset”

Ambient temperature of humidity generator is below operating
temperature.

Humidity generator is above allowed limit. Check water supply or
ambient conditions.

Factory calibration has been reset to default. Please contact
Fluke Calibration.

40

RHapid-Cal Humidity Generator

User-Replaceable Parts and Accessories

User-Replaceable Parts and Accessories

Table 15 lists the part numbers of each user-replaceable part or accessory for
the Product. For more information on these items and accessories, refer to
Contact Fluke Calibration.

Table 15. User-Replaceable Parts and Accessories

Description

Mains Power Cord - North American 284174 1
Mains Power Cord - Europe 769422 1
Mains Power Cord - UK 769455 1
Mains Power Cord - Swiss 769448 1
Mains Power Cord - Australia 658641 1
Mains Power Cord - South Africa 782771 1
Mains Power Cord - Thailand 4362094 1
Mains Power Cord - Denmark 2477031 1
Mains Power Cord - Brazil 3841347 1
5128A Safety Information 4758293 1

 FUSE 5 x 20 mm 4 Amp (F4A 250V) Fast Blow 3712591 2
 FUSE 12 V dc output fuse (F1A 250V fuse). 3712540 1

Desiccant cartridge 4791251 1
Grommet kit and fill syringe 4791297 1

Fluke Calibration Part

Number

Total Quantity

Square door with 5 ports 4791272 1

Accessories

Round door with 5 ports 4791260 1
Clear door with internal shelf 4791285 1

41

1.00 inch

4.30 inches

4.88 inches

CHAMBER COVER

MINIMUM

WORKING AREA

MAXIMUM

42

FRONT PANEL FACE

OF FLUKE 5128A

FRONT RIGHT CORNER

OF FLUKE 5128A

Figure 11. Working Volume Template