Omega Products HX85 Installation Manual

HX80 SERIES

OPERATORS MANUAL

January 2012

Rev. E

MADE IN

HX80 SERIES

QUICK STARTUP GUIDE – Page 1

STARTUP

WHEN USING PROBE ONLY:

1. Mount the Probe in position to measure the desired gas.

2. Connect Probe wiring by cutting off connector or using a mating
connector, as shown below:

ITEM RIBBON CABLE WIRE #

Power Supply – Pos. 7
Power Supply – Neg. 1 (blue tracer)

Output 1 – Pos. 2
Output 2 – Pos. 6
Output 3 – Pos. 8

Output Common 4
Serial Output – TX 5
Serial Output – RX 3

Notes: Connect only the Outputs desired. See drawing in the HTPB Manual for
further connection details.

Do not apply DC Power until all wiring is completed.

1

HX80 SERIES

QUICK STARTUP GUIDE – Page 2

WHEN USING PROBE WITH ELECTRONICS UNIT:

1. Mount the Probe and Electronics Unit.

2. Connect cable from Probe to Electronics Unit
(if applicable).

3. Connect Power Supply to Electronics Unit.

4. Connect Analog Outputs of Electronics Unit.

5. Connect Digital Output of Electronics Unit.

6. Connect Alarm Relays of Electronics Unit.

7. Connect RS-232 Serial Port of Electronics Unit.

ITEM CONN. TERM.

Power Supply (+) J8 2

Power Supply (-) J8 1
Analog Out 1 (+) J9 1

Analog Out 1 (-) J9 2

Analog Out 2 (+) J9 3

Analog Out 2 (-) J9 4

Analog Out 3 (+) J9 5

Analog Out 3 (-) J9 6

Alarm Relay 1 J2 1
Alarm Relay 1 J2 2
Alarm Relay 2 J2 3
Alarm Relay 2 J2 4

RS-232 TX J6 2
RS-232 RX J6 3

RS-232 RTN J6 5

Notes:
Connect only the Outputs desired. See the HX80 Manual for details.
Do not apply DC Power until all wiring is completed.

2

TABLE OF CONTENTS Page

1.0 Quick Startup 1

List of Illustrations 4

List of Tables 4

2.0 Introduction 5

2.1 General Description 5

2.2 Specifications Summary 6

2.3 Model Descriptions 7

2.4 Available Options 8

3.0 Installation 10

3.1 Mounting the Probe 10

3.2 Mounting the Electronics Unit 11

3.3 Electrical Wiring 11

3.3.1 Probe Only 11

3.3.2 Probe with Electronics 13

4.0 Basic Block Diagram 16

4.1 Probe Assembly 16

4.2 Electronics Module 17

4.3 Complete System 17

5.0 Operation 19

5.1 Initial Bench Testing 19

5.2 Normal Operation 19

5.3 Factory Default Conditions 19

5.4 RS-232 Serial Port 21

5.4.1 Serial Port Setup 21

5.4.2 Changing the Digital Display 21

5.4.3 Changing the Output Ranges 22

5.4.4 Programming the Alarm Relays 23

5.4.5 Calibrating the Analog Outputs 24

6.0 Maintenance 25

6.1 Sensor Circuit Board 25

6.1.1 Replacing the Sensor Board 25

6.1.2 Removing Components 25

6.1.3 Sensor Reassembly 26

7.0 Specifications 27

3

LIST OF ILLUSTRATIONS Page

2-1 Some HX80 Configurations 5

3-1 System with Sample Cell 10

3-2 Installing the Mounting Lugs 11

3-3 Probe Wiring, Ribbon Cable 12

3-3a Probe Wiring 13

3-4 Electronics Unit Wiring 15

4-1 Probe Block Diagram 16

4-2 System Block Diagram 18

6-1 Removing Retaining Ring 25

6-2 Sensor Exploded View 26

LIST OF TABLES Page

2-1 Standard Configurations 7

2-2 Measurement Ranges 8

3-1 Probe Wiring, Ribbon Cable 12

3-1a Probe Wiring 13

3-2 Electronics Wiring 14

3-3 Serial Port Wiring 14

5-1 Standard Output Scaling 20

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2.0 INTRODUCTION

2.1 GENERAL DESCRIPTION

The HX80 Series is a family of humidity probes and electronic modules that offer a
variety of measurement parameters with high accuracy. In addition to Percent Relative
Humidity (%RH), probes are available to also measure Temperature and Pressure.
Electrical analog and digital outputs are provided for not only these measured
parameters, but may be provided for microprocessor- computed parameters as well.
These include parts-per-million by volume (ppmv), parts-per-million by weight (ppmw),
grains of water per pound of dry gas (gr/lb), and others.

The HX80 system is designed for ease of installation and operation. Field-replaceable
sensor modules have standardized outputs for interchangeability without recalibration.
The power requirement is a common unregulated DC power supply. User-available
electrical outputs include linear analog voltage (or optional current), a digital bi­directional serial port, and alarm relays. Mounting options include Wall Mount, Remote
Mount, and Duct Mount configurations. Additional options include high temperature and
high pressure probes. A remote or local Display Unit (Type DIS) is available, with a
two-line LCD display, alarm relays, and three 4 to 20 mA electrical outputs.

Figure 3-1 Some of the Available HX80 Configurations

a. Stand-alone Probe

b. Remote Mount with Display

Option

5

2.2 SPECIFICATIONS SUMMARY

(See Specifications for additional information)

2.2.1 STAND-ALONE PROBE

Analog Outputs: 0 – 10 Vdc (X3)

Digital Output: RS-232C

Power Supply: 18 to 30 Vdc, unregulated, 50 mA max.

RH Accuracy: +/- 1% nominal

Temp. Accuracy: +/- 0.5°C

Mounting: Cable Length: 6 feet

Fitting: ¾ inch stainless steel

NPT thermocouple fitting

Dimensions: Length: 8 inches

Diameter: ¾ inch

Materials: Housing: Stainless Steel

Filter: Sintered Stainless Steel (removable)

2.2.2 PROBE WITH ELECTRONICS UNIT

Analog Outputs: 4 to 20 mA (X3)

Digital Output: RS-232C, bi-directional

Alarm Relays: Form A (SPST, NO) X2

Power Supply: 18 to 30 Vdc unregulated, 50 mA max.

RH Accuracy: +/- 1% nominal

Temp. Accuracy: +/- 0.5°C

Electronics Housing Protection:

IP66 (NEMA 4X) Dust tight and moisture resistant

6

Table 2-1 HX80 Series, Standard Available Configurations

MODEL NO.

HX85 X
HXB85 X
HXP85 X

HX86 X
HXB86 X
HXP86 X
HX86N x
HX85A x

HX85BA x
HX85PA x

HX86A x

HX86BA x
HX86PA x

SENSOR ONLY

SENSOR WITH

ELECTRONICS MODULE

2.3 HX80 SERIES MODEL DESCRIPTIONS

HX85 – A Humidity/Temperature probe providing RH, Dew Point, and Temperature

outputs.

HXB85 – A Humidity/Temperature/Barometric Pressure probe providing RH,

Temperature, and Pressure outputs.

HXP85 – A Humidity/Temperature/High Pressure probe providing RH, Temperature,

and Pressure outputs.

HX86 – A Humidity/ High Temperature probe providing RH, Temperature, and Dew

Point outputs, with remote Electronics Unit including Digital Display.

HXB86 – A Humidity/High Temperature/Barometric Pressure probe providing RH,

Temperature, and Pressure outputs, with remote Electronics Unit including Digital
Display.

HXP86 – A Humidity/High Temperature/High Pressure probe providing RH,

Temperature, and Pressure outputs, with remote Electronics Unit including Digital
Display.

HX86N – Identical to HX86, with Remote Electronics Unit, but with no Digital Display.
HX85A – A Humidity/Temperature probe providing RH, Dew Point, and Temperature

outputs with an operating temperature up to 120C.

7

HX85BA – A Humidity/Temperature/Ba rometric Pressure probe providing RH,

Temperature, and Pressure outputs with an operating temperature up to 120C.

HX85PA – A Humidity/Temperature/High Pressure probe providing RH, Temperature,

and Pressure outputs with an operating temperature up to 120C.

HX86A – A Humidity/ High Temperature probe providing RH, Temperature, and Dew

Point outputs, with remote Electronics Unit including Digital Display with an operating
temperature up to 120C.

HX86BA – A Humidity/High Temperature/Barometric Pressure probe providing RH,

Temperature, and Pressure outputs, with remote Electronics Unit including Digital
Display with an operating temperature up to 120C.

HX86PA – A Humidity/High Temperature/High Pressure probe providing RH,

Temperature, and Pressure outputs, with remote Electronics Unit including Digital
Display with an operating temperature up to 120C

2.4 AVAILABLE OPTIONS

HX80-DIS – Remote electronics module with two-line LCD digital display, three 4 to 20

mA analog outputs, RS-232C, and two programmable alarm relays. This unit can be
added to existing Probes in the field.

HX80-NDIS – Similar to HX80-DIS but without Digital Display
HX80- SENSOR – Field-replaceable sensor module for RH/Temperature.

Interchangeability accurate to published specification.

HXP80-SENSOR – Field-replaceable sensor module for RH/Temperature/Pressure.

Interchangeability accurate to published specification.

HXB80-SENSOR – Field-replaceable sensor module for RH/Temperature/Barometric

Pressure. Interchangeability accurate to published specification.

HX80-CHAMBER – Sample chamber with inlet and outlet fittings.

Table 2-2 HX80 Series Sensor Actual Measurement Ranges.

MODEL NO. OUTPUT 1 OUTPUT 2 OUTPUT 3

HX85

MEASUREMENT RANGE 5 to 95% -20 to +70ºC -60 to +30ºC

HXB85

PERCENT RH AIR TEMP. DEW POINT

PERCENT RH AIR TEMP. BAR. PRESSURE

8

MEASUREMENT RANGE 5 to +95% -20 to +75ºC 10 to 1100 MB

HXP85

MEASUREMENT RANGE 5 to +95% -20 to + 75ºC 0 to 200 psia

HX86

MEASUREMENT RANGE 5 to 95% -20 to +115ºC -40 to +60ºC

HXB86

MEASUREMENT RANGE 5 TO 95% -20 to +115ºC 10 to 1100 MB

HXP86

MEASUREMENT RANGE 5 TO 95% -20 to +115ºC 0 to 200 psia

HX85A

MEASUREMENT RANGE 5 TO 95% -20 to +120ºC -60 to +40ºC

HX85BA

MEASUREMENT RANGE 5 TO 95% -20 to +120ºC 10 to 1100 MB

HX85PA

MEASUREMENT RANGE 5 TO 95% -20 to +120ºC 0 to 200 psia

HX86A

MEASUREMENT RANGE 5 TO 95% -20 to +120ºC -60 to +40ºC

HX86BA

MEASUREMENT RANGE 5 TO 95% -20 to +120ºC 10 to 1100 MB

HX86PA

MEASUREMENT RANGE 5 TO 95% -20 to +120ºC 0 to 200 psia

NOTES: 1. THE STANDARD RANGES ARE FIELD PROGRAMMABLE

VIA THE RS-232 PORT.

2. SEE TABLE 5-1 FOR STANDARD FACTORY SCALING.

PERCENT RH AIR TEMP. ABS. PRESSURE

PERCENT RH AIR TEMP. DEW POINT

PERCENT RH AIR TEMP. BAR. PRESSURE

PERCENT RH AIR TEMP. ABS. PRESSURE

PERCENT RH AIR TEMP. DEW POINT

PERCENT RH AIR TEMP. BAR. PRESSURE

PERCENT RH AIR TEMP. ABS. PRESSURE

PERCENT RH AIR TEMP. DEW POINT

PERCENT RH AIR TEMP. BAR. PRESSURE

PERCENT RH AIR TEMP. ABS. PRESSURE

9

3.0 INSTALLATION

3.1 MOUNTING THE PROBE

The Probe includes a stainless steel mounting sleeve, commonly called a thermocouple
mount. It has a tapered male ¾-inch NPT pipe thread. The female mating fitting, user­supplied, should be mounted in a gas-tight manner to a flat surface of a duct or
chamber wall containing the gas to be measured.

To install the mount and Probe:

1. Separate the two parts of the mounting sleeve.

2. Screw the front portion of the mounting sleeve (the tapered NPT fitting) into the
pre-mounted mating fitting. Teflon™ tape may be used for a good seal. Do not
over-tighten.

3. Insert the Probe into the rear portion, and screw this part of the mount into the
previously mounted front portion, so that the Probe is gripped snugly. Do not
over-tighten. As much of the Probe as possible should protrude inside the area
to be measured, to avoid possible laminar flow errors.

If the optional sample chamber is to be used, simply screw it down to any flat surface,
and connect ¼ inch OD tubing to the inlet and outlet compression fittings.

Figure 3-1, System with Sample Cell, ready for mounting

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3.2 MOUNTING THE REMOTE ELECTRONICS MODULE

MOUNTING CONSIDERATIONS

1. If the Digital Display has been provided, is it easily visible?

2. Is the location convenient for routing electrical wiring?

3. Is the module within 6 feet (1.8 meters) of the Sensor location?

Use a small hammer to tap in the pins that hold the four corner mounting lugs in place.
See Figure 3-2 below. Mount the box to a flat surface with screws or bolts through the 4

mounting holes.

Figure 3-2 a,b,c,d
Installing Mounting Lugs

3.3 ELECTRICAL WIRING

3.3.1 PROBE ONLY

See Wiring Table 3-1 and Figure 3-3 below.

1. Connect Power Supply wiring as shown.

2. Connect the Analog Output wiring as shown. Three 0 to 10Vdc outputs are
available. Connect Outputs 1, 2, and 3 as required.

3. Connect the RS-232 Serial Output if desired. Only 2 wires are required if
the output is needed for transmitting information only. A third wire is
added for bi-directional communications with the serial port.

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4. Table 3-1 Hx80 Series Probe (with Ribbon Cable)
Wiring Table

ITEM RIBBON CABLE WIRE #

Power Supply – Pos. 7
Power Supply – Neg. 1 (blue tracer)

Output 1 – Pos. 2
Output 2 – Pos. 6
Output 3 – Pos. 8

Output Common 4

Serial Output – TX 5

Serial Output – RX 3

1 (WITH BLUE TRACER)

PWR SUPPLY – NEG.

2 OUTPUT 1 – POS.
3 SERIAL OUT -- RX
4 OUTPUT COMMON
5 SERIAL OUT -- TX
6 OUTPUT 2 – POS.
7 PWR SUPPLY – POS.
8 OUTPUT 3 – POS.
9 NOT USED
10 NOT USED

Figure 3-3 HX80 Series Probe (with Ribbon Cable)

Wiring Diagram

12

Table 3-1a HX80 Series Probe (with Discrete Wires)
Wiring Table

ITEM COLOR CODE

Power Supply – Pos. Yellow
Power Supply – Neg. Green
Output 1 – Pos. Brown
Output 2 – Pos. Red
Output 3 – Pos. Orange
Output Common Black
Serial Output – TX Blue
Serial Output – RX White
Serial Common Green

Figure 3-3a HX80 Series Probe (with Discrete Wires) Wiring Diagram

3.3.2 PROBE WITH ELECTRONICS MODULE

See Tables 3-2, 3-3, and Figure 3-4 below.

Notes:

1. Cable bushings are shipped separately. Carefully tap out the desired
knockouts, and mount the bushings.

2. We recommend that you route the Probe Cable through a bushing on the
left. Route all other wiring through the bushing on the right.

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1. Run the cable from the Probe to the connector labeled Probe Input.

2. Wire the Power Supply as shown in Table 3-2.

3. Wire the three 4 to 20 mA Analog Outputs and Alarm Relays as shown in Table
3-2 if desired.

4. Connect to the RS-232C Serial Port at J6 if desired.

Table 3-2 Electronics Unit Wiring Table

ITEM CONN. TERM.

Power Supply (+) J8 2
Power Supply (-) J8 1
Analog Out 1 (+) J9 1
Analog Out 1 (-) J9 2
Analog Out 2 (+) J9 3
Analog Out 2 (-) J9 4
Analog Out 3 (+) J9 5
Analog Out 3 (-) J9 6
Alarm Relay 1 J2 1
Alarm Relay 1 J2 2
Alarm Relay 2 J2 3
Alarm Relay 2 J2 4

Table 3-3 J6 Wiring Table

DB-9 SERIAL CONNECTOR ITEM

Pin 2 TX
Pin 3 RX
Pin 5 RTN

14

A

A

OUTPUT 1

RTN 1

OUTPUT 2

RTN 2

Figure 3-4 Electronics Unit Wiring

PROBE CONN.

RS232

OUTPUT 3

RTN 3

24 VDC

NEG -

POS +

LARM 2

LARM 1

15

4.0 BASIC BLOCK DIAGRAM THEORY OF OPERATION

4.1 PROBE ASSEMBLY

See Figure 4-1, the Probe Assy. Basic Block Diagram.

The Probe Assembly is a stand-alone, completely self-contained measuring system. All
units include the RH and Temperature Sensors, and some optional probes include a
Pressure Sensor as well. The field-replaceable Sensor Circuit Board has standardized
output levels for all three measured parameters. Therefore, boards may be quickly
replaced while in operation without the need for recalibration, maintaining full system
accuracy. The Microprocessor performs the system control, parameter calculation, and
serial digital communications. Digital-to-Analog (D-A) conversion provides three 0 to 10
Vdc linear Analog Outputs corresponding to the measured and/or calculated
parameters.

The serial digital RS-232 interface is bi-directional, allowing the user to not only receive
and record measured information, but to remotely control output scaling, alarm relay
setpoints, and other functions as well.

SENSOR BOARD PLUG-IN ASSY.

RH

SENSOR

TEMP.

SENSOR

PRESSURE

SENSOR

NORMALIZATION - CALIBRATION

STAGE

SENSOR BOARD PLUG-IN CONNECTOR

MICROPROCESSOR

D-A D-A D-A

0 - 10 VDC

RH OUT

0 - 10 VDC

TEMP. OUT

PRESSURE OUT

0 - 10 VDC

RS-232

(TX)

SERIAL PORT

RS-232

(RX)

Figure 4-1 Basic Block Diagram, Probe Assy

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4.2 HX80-DIS ELECTRONICS MODULE

Although the Probe may be used as a stand-alone measuring device (HX85), it also
may be connected to the type DIS remote display unit, for additional capability. This
combination is called the HX86. A complete HX86 system consists of the Probe, the
interconnecting 6 foot (1.8 meter) cable, and the electronics module. Outputs of the unit
include a Serial Port, two Alarm Relays and three 4 to 20 mA Analog Outputs. A two­line LCD Digital Display is also included.

4.3 THE COMPLETE HX86 SYSTEM

Figure 4-2 is a basic block diagram of the complete Humidity, Temperature and
Pressure measuring system. The remote Probe is connected, via the attached cable, to
the electronics module. The system is completely controlled by the microprocessor in
this module.

The three sets of analog voltage outputs from the Probe are routed through the Analog
Scaling and Selection stage. The scaling of these output signals may be programmed
by the user to any desired range by using the RS-232 Serial Port. The bi-directional
RS-232 is brought out to a connector in the electronics module. The user can also
program the two Alarm Relay set points via this digital interface. The built-in LCD
Digital Display, which provides information on all measured parameters, is also
controlled by the microprocessor. In addition, the microprocessor is used to calculate
other parameters than those directly measured by the sensors in the Probe. These may
be shown on the Digital Display, and they are also available on both the analog and
digital (RS-232) outputs. The Alarm Relays may also be set for these calculated values.

17

Figure 4-2 System Basic Block Diagram

RH

SENSOR

HTPB PROBE ASSY.

DIGITAL

DISPLAY

TEMP.

SENSOR

ALARM

RELAY

#1

PRESSURE

SENSOR

(OPTION)

6 FT. SENSOR CABLE

MICROPROCESSOR

ALARM

RELAY

#2

SERIAL

PORT

(TX) (RX)

ANALOG

OUTPUTS

(0 - 10V X3)

ANALOG

SCALING

AND

SELECTION

ELECTRICAL CONNECTORS

ALARM

1

ALARM

2

USER INTERFACE

18

RS-232

(TX) (RX)

ANALO G OUTPUTS

1 2 3

5.0 OPERATION

5.1 INITIAL BENCH TESTING

New units may be tested on the bench before installation, if desired.

For units consisting of the Probe only –

1. Connect a proper Power Supply to the correct wires.

Caution: Observe polarity!

2. Using a DC Voltmeter, measure the 0 to 10 Vdc Output and confirm that it

corresponds to the room condition. (Humidity, Temperature, etc.)

For systems consisting of the Probe and the Electronics Unit –

1. Connect the Probe to the Electronics Module.

2. Connect a proper Power Supply to the correct terminals.

Caution: Observe polarity!

3. Measure the 4 to 20 mA Output as above, or read the Digital Display.

Confirm that the reading corresponds to the room condition. (Humidity,
Temperature, etc.)

5.2 NORMAL OPERATION

Note:

This section assumes that all required electrical wiring and mounting has
been completed. See the Installation section for further information if
necessary.

Use of the HX80 series of probes is extremely simple. There are no controls to operate
during normal use, as these devices are designed for long-term unattended operation.
With the Analog Outputs, Digital Outputs, and/or Alarm Relays connected to a Data
Acquisition System, Recorder, Process Controller, Computer, or Terminal, the user has
only to periodically monitor the system for normal operation.

5.3 FACTORY DEFAULT RANGES

The scaling of the default measurement ranges may be changed in the field via the
Serial Port if required. See Section 5.4 below for range-changing instructions.

The following ranges are set at the Factory. They correspond to the three separate 0 to
10 Vdc analog outputs that are provided. The scaling of these ranges may be changed
in the field via the Serial Port if required.

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HX85/HX85A 0 to 100% -20 to 80OC/120 OC N/A -60 to 40˚C
HXB85/HX85BA 0 to 100% -20 to 80OC/120 OC 750 to 1100 mb
HXP85/HX85PA 0 to 100% -20 to 80OC/120 OC 0 to 200 psia

HX86/HX86A 0 to 100% -20 to 120OC N/A -60 to -40˚C
HXB86/HX86BA 0 to 100% -20 to 120OC 750 to 1100 mb
HXP86/HX86PA 0 to 100% -20 to 120OC 0 to 200 psia

Notes:

Table 5-1 Standard Output Scaling

MODEL R.H. TEMP. PRESSURE DEW POINT

HX86N 0 to 100% -20 to 120 OC N/A -60 to -40˚C

1. Although the Factory default range for the HXB85, HX85BA,
HXB86 and the HX86BA is 750 to 1100 mb, it can be reprogrammed in
the field over a range of 10 to 1100 mb.

2. If you have the Type DIS Humidity Multi-I/O accessory, the Analog
Outputs are 4 to 20 mA.

20

5.4 USING THE RS-232C SERIAL PORT TO PROGRAM YOUR

SETTINGS

5.4.1 SERIAL PORT SETUP

Plug a standard RS-232 cable into the DB-9 connector on the circuit board in the Type
DIS Humidity Multi I/O Electronics Unit. Plug the other end into your terminal or
computer. Use a Terminal Emulation program such as Hyperterminal. Program the
Hyperterminal settings as follows:

• Baud Rate: 19.2K

• Data Bits: 8

• Parity None

• Stop Bit 1

• Flow Control None

You should now see flowing data on your monitor,
displaying the same information as the Multi I/O front
panel Digital Display, with a rapid update rate. If you do
not, check your serial port settings and connections.

NOTE: WHEN PROGRAMMING ALPHABETIC CHARACTERS,
USE UPPER CASE ONLY.

5.4.2 CHANGING THE DIGITAL DISPLAY

You can select any measured or calculated
parameters to appear on the front panel Digital
Display. Proceed as follows:

Press the
“Escape” key
on your
keyboard. You
will see
“D)isplay C)al

Outputs” as
shown here.
Press “D”, selecting to change the Display. (We
will C)alibrate the Outputs later.) You will then be given a choice whether to keep the
present settings or to change them. For this example, we will C)hange them. Press

21

“C”. You can then select the parameter to insert by cycling through the options using
the Space Bar. In this case, we will change VALUE 1, the Dew Point reading, from
DPoC to DPoF. Press Enter to save your change and advance to the next value. Next,
do the same for Air Temperature. When completed, press Enter again to save and

advance. For this example, we will choose not to
change the %RH value. Instead, press “X” for eX)it.

When programming is completed, press “A” to
accept the changes.

5.4.3 CHANGING THE OUTPUT RANGES

The next window to be seen will be the Output
Settings screen. Here, you can modify the 4 to 20
mA Analog Output ranges. To enter this mode,
press “C” for C)hange. You will see the Set Output
screen shown here.

To change Output 1, select “1”. You will see
this screen, which shows the present settings
for Output 1.

22

Example: We would like to change DPoF to a range of -40 to 200 oF. Press Enter.
Enter -40. Press Enter again. Enter 200. Press Enter again. To Save the Changes,
press “Y” for Y)es. To accept the changes, press “A” for A)ccept.

5.4.4 PROGRAMMING THE ALARM RELAYS

The system will then step to the
Alarm Relay mode. The two relays
are Form A, (single-pole, single­throw), normally open. You can
independently program the “ON”
point and the “OFF” point for each
relay. To enter the menu, press
“C” for C)hange.

We would like to change Alarm 2 to
these parameters:

Open > a reading of 10 oC
Close < a reading of 10 oC

NOTE: IN ACTUAL OPERATION YOU SHOULD PROGAM IN A SMALL OVERLAP,
SO THAT THE RELAY DOES NOT CHATTER WHEN THE MEASURED READING IS
EXACTLY AT THE SETPOINT. THIS IS CALLED “HYSTERESIS.”

Press “2” to set Alarm 2. You will note that Alarm 2 is set for Air Temperature, AToC.
Under OPEN, insert 10 and press “Enter.” Under CLOSED, insert 10 and press “Enter.”

23

You will be asked to Save the Changes. Press “Y” for Y)es.

Then, press “A” for A)ccept.

The program will then automatically return to the normal mode, displaying data that is
continuously updated.

5.4.5 CALIBRATING THE ANALOG OUTPUTS

If you have a precise milliammeter, you can easily calibrate the three 4 to 20 mA analog
outputs. In order to utilize this convenient capability, connect the meter in series with
one of the analog outputs and the load.

Press the “Escape” key on your keyboard, which will interrupt the data stream and give
you the choice of D)isplay or C)al Outputs. Select “C”.

In order to calibrate Output 1, press “1”. You will then be able to insert the desired
current value at the ¼ FS (25% of Full Scale) point and at the 3/4FS (75% of Full Scale)
point. For 4 to 20 mA, 1/4FS is 8 mA, and 3/4FS is 16mA.

Insert these values, pressing “Enter”
after each one. You will then see a
range of what the milliammeter should
read in order to attain the desired
accuracy.

Then select “X” for eX)it. The system
will now return to the normal data

reading mode.

24

6.0 MAINTENANCE

6.1 SENSOR CIRCUIT BOARD

Inside the barrel of the Sensor probe, mounted directly at the tip, is the plug-in sensor
circuit board. This board has been calibrated at the Factory for a standard output level.
Since all boards have been calibrated for the same normalized level, they may be
replaced in the field without the requirement for recalibration, while maintaining the full
published system accuracy specification.

6.1.1 REPLACING THE SENSOR CIRCUIT BOARD

See Figure 6-1. For the HX85 and the HX86 series only, at the tip of the Sensor probe

is a snap-ring, or retaining ring (for the HX85A and HX86A series the filter cover is a
scew on cover). It must be removed in order to gain access to the Sensor board.

There is a groove at one end

of the ring. Using a very small
screwdriver or a small knife blade
inserted into the groove in the retaining
ring, lift it out of the machined groove
in the inside of the sensor shield
barrel. The ring can then be removed,
allowing access to the interior of the
sensor assembly.

Figure 6-1 Removing the Retaining Ring

6.1.2 REMOVING THE RETAINING COMPONENTS

Figure 6-2 shows the sequence of parts that must be removed in order to gain access to
the sensor board. All are easily removed once the retaining ring is out. Store them
carefully for re-installation later in the proper sequence.

The final item to be removed in the sequence is the plug-in sensor circuit board, which
can be seen through the slot in the sensor shield. There is a small hole near the tip of
the board to aid in removal. Inserting a small screwdriver in this hole and pulling
upward gently, unplug the board from the socket built into the probe.

Note: The small humidity sensor can be seen mounted near the tip of the board.
This is fragile. Take care not to break it during board removal or installation.

25

6.1.3 SENSOR REASSEMBLY

Carefully plug the new sensor circuit board into the socket, noting that it is installed at
the correct angle and properly aligned. Using a small screwdriver in the hole near the
tip, press it down sufficiently so that it is fully inserted in the socket.

Install the bushing in the
direction shown in Figure 6-2.
Then install the spring, O-ring,
and the sintered filter. Finally,
while pressing on the end of the
sintered filter to compress the
spring, snap the retaining ring
back into the slot on the inside
of the sensor shield. Be sure
that it is inserted completely, so
that it will securely retain the
sensor components in place.

F
i
g
u
r
e

6-2 Sensor Exploded View
For the HX85 and HX86 series only, not for the
HX85A or HX86A series

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Sensor exploded view for the
HX85A or HX86A series

7.0 SPECIFICATIONS

Note: See Table 2-2 for actual measurement ranges.
HX85 and the HX85A (Sensor Only)

Measured Parameters – RH/Temp.
RH Accuracy – +/- 1% RH
Temp. Accuracy – +/- 0.5oC
Output Information – RH, Temp., DP
Electrical Outputs – 0 to 10 Vdc (X3)
RS-232C

HXB85 and the HX85BA (Sensor Only)

Measured Parameters – RH/Temp./Barometric Pressure
RH Accuracy – +/- 1% RH
Temp. Accuracy – +/- 0.5
Pressure Accuracy – +/- 5 mb
Output Information – RH, Temp., Pressure
Electrical Outputs – 0 to 10 Vdc (X3)
RS-232C

HXP85 and the HX85PA(Sensor Only)

Measured Parameters – RH/Temp./Pressure
RH Accuracy – +/- 1% RH
Temp. Accuracy – +/- 0.5
Pressure Accuracy – +/- 0.75 psi
Output Information – RH, Temp., Pressure
Electrical Outputs – 0 to 10 Vdc (X3)
RS-232C

o

C

o

C

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HX86 and the HX86A (Sensor with Electronics Module)

Measured Parameters – RH/Temp.
RH Accuracy – +/- 1% RH
Temp. Accuracy – +/- 0.5oC
Output Information – RH, Temp., DP
Electrical Outputs – 4 to 20 mA (X3)
RS-232C
Alarm Relays (X2)
Digital Display – LCD, 2-line

HXB86 and the HX86BA (Sensor with Electronics Module)

Measured Parameters – RH/Temp./Barometric Pressure
RH Accuracy – +/- 1% RH
Temp. Accuracy – +/- 0.5oC
Pressure Accuracy – +/- 5 mb
Output Information – RH, Temp., Pressure
Electrical Outputs – 4 to 20 mA (X3)
RS-232C
Alarm Relays (X2)
Digital Display – LCD, 2-line

HXP86 and the HX86PA (Sensor with Electronics Module)

Measured Parameters – RH/Temp./ Pressure
RH Accuracy – +/- 1% RH
Temp. Accuracy – +/- 0.5oC
Pressure Accuracy – +/- 0.75 psi
Output Information – RH, Temp., Pressure
Electrical Outputs – 4 to 20 mA (X3)
RS-232C
Alarm Relays (X2)

Digital Display – LCD, 2-line

Electrical Outputs

Systems with Probe only –

0 to 10 Vdc (X 3) @ 10 mA max.
RS-232C (bi-directional)

Systems with Probe and Electronics Unit—

4 to 20 mA (X3) into 500 Ω max.
Alarm Relay (X2) Form A (SPST, NO) rated at 3A/250 Vac
RS-232C (bi-directional)

Serial Output (All Units)

RS-232C to DTE device. 19.2 kilobaud, 8 bits data, 1 stop bit, no parity

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Power Requirements

18 to 30 Vdc unregulated, 50 mA max.

Dimensions

Remote Sensor – Diameter: ¾ in. OD (1.9 cm)
Length: 8 inches (20.3 cm)
Cable Length – 6 feet (1.8 meters)
Consult Factory for longer lengths.

Electronics Module –

Outside Dimensions (HWD)

5.1 X 3.7 X 2.2 inches (13 X 9.4 X 5.6 cm)

Mounting Centers

4.5 2 X 3.11 inches (11.5 X 7.9 cm)

Sensor Pressure Rating
200 psia maximum

Sensor Sintered Filter
Material – Stainless Steel

Porosity – 40 microns

29

Notes

30