Honeywell HIH-6130, HIH-6131 Technical Note

Technical Note

Using Alarms on the Honeywell HumidIcon™ Digital
Humidity/Temperature Sensors: HIH-6130/6131 Series

Alarm functionality

How to combine alarms

Configuration options

How do disable alarms

Digital Humidity/

Temp. Sensor

VDD

VCORE

VSS

NC

SCL

SDA

ALARM_LOW

ALARM_HIGH

VSUPPLY = 2.3 Vdc to 5.5 Vdc

GND

0.1 µF

0.22 µF

8

3

4

5

6

1

2

7

GND

Digital Humidity/

Temp. Sensor

VDD

VCORE

VSS

NC

SCL

SDA

ALARM_LOW

ALARM_HIGH

VSUPPLY = 2.3 Vdc to 5.5 Vdc

GND

0.1 µF

0.22 µF

8

3

4

5

6

1

2

7

GND

12 V

12 V

Alarm_High_On
Alarm_High_Off

Alarm_Low_On
Alarm_Low_Off

Alarm_High_Off

Alarm_High_On

Alarm_Low_On

Alarm_Low_Off

Humidity

Time

High Alarm On

High Alarm Off

Low Alarm On

Low Alarm Off

NOTICE

Alarm registers may only be accessed using Command
Mode. (See Technical Note “Entering and Using Command

Mode on Honeywell Digital/Temperature Sensors”.)

1.0 Introduction

The Honeywell HumidIcon™ Digital Humidity/Temperature
Sensors: HIH-6130/6131 Series support up to two configurable
alarm outputs which can be used to monitor whether the
ambient humidity has risen or fallen below preprogrammed
values. The alarms have configurable thresholds, polarity and
outputs to provide flexible interfacing with other components.

This document describes:

2.0 Alarm Output

The alarm output can be used to indicate whether a predefined
humidity level has been reached. The alarms can be
configured in two ways:

As an open-drain output to drive a load connected to VDD

(see Figure 1).

Figure 1. Alarm Open Drain Output Application Circuit
Example

If available, both alarms can be used at the same time. The
alarm outputs are updated when a measurement cycle is
completed.

3.0. Alarm Functionality

There are four registers associated with the alarm thresholds
(see Appendix A for the EEPROM addresses):

Each register contains a 14-bit value that determines the
humidity at which the alarm turns on or off. The two
Alarm_High registers set the hysteresis of the Alarm_High pin,
while the two Alarm_Low registers set the hysteresis for the
Alarm_Low pin (see Figure 3).

Figure 3. Alarm Hysteresis

As a full push-pull driver for interfacing with a

microcontroller or to drive a high voltage external device,
(see Figure 2).

Figure 2. Alarm Push-Pull Output Application Circuit
Example

Alarm_High_On register determines the humidity

threshold where the high alarm is activated.

Alarm_High_Off register determines the humidity

threshold where the high alarm is deactivated.

Alarm_Low_On register determines the humidity threshold

where the low alarm is activated.

Sensing and Control

Alarm_Low_Off register determines the humidity threshold

where the low alarm is deactivated.

Using Alarms on the Honeywell HumidIcon™ Digital
Humidity/Temperature Sensors: HIH-6130/6131 Series

Humidity (%RH) =

RegisterContents

(214 - 1)

x 100%

Alarm_High_On =

80 %RH

100%

x (214 - 1) = 13107 or 0 x 3333

Alarm_Low_On =

10 %RH

100%

x (214 - 1) = 1638 or 0 x 0666

High Alarm

Alarm = Off

Measurement >

Alarm_High_On?

Alarm = On

Measurement <

Alarm_High_Off?

Yes

Yes

No

No

Low Alarm

Alarm = Off

Measurement <

Alarm_Low_On?

Alarm = On

Measurement >

Alarm_Low_Off?

Yes

Yes

No

No

Bit

Description

7

Alarm_Low Polarity:
0 = Active_ High, 1 = Active_ Low

8

Alarm_Low Output Configuration:
0 = Full_Push-Pull, 1 = Open_Drain

9

Alarm_High Polarity:
0 = Active_High, 1 = Active_Low

10

Alarm_High Output Configuration:
0 = Full_Push-Pull, 1 = Open_Drain

The contents of the alarm registers correspond to humidity as
follows:

Thus, 0 %RH = 0x0000 and 100 %RH = 0x3FFF or 16383.

For example, to enable the Alarm_High output at humidity
above 80 %RH:

Similarly, to enable the Alarm_Low output at humidity below
10 %RH:

Alarm hysteresis is equivalent to the difference between the
registers.

A minimum hysteresis of 3% RH is recommended.

High and Low Alarm flow charts are shown in Figure 4.

Figure 4. High and Low Alarm Flow Charts

4.0 Alarm Configuration

A fifth register, the Customer Configuration Register (see
Appendix B), is associated with the alarm outputs and contains
the configuration bits. Both alarms may be configured
independently using the Alarm_Low_Cfg and Alarm_High_Cfg
bits (see Table 1).

Table 1. Customer Configuration Register Alarm Bits

For applications which interface to other logic circuits, such

as a micro-processor or to drive an external device, Full
Push-Pull is recommended.

For driving loads directly connected to the sensor voltage

supply open drain would be a typical choice (see Figures 1
and 2).

The polarity of the alarm output is configured using the Alarm
Polarity bits. The ability to change the alarm polarity gives the
user flexibility in how the sensor interfaces with an application.

In the example shown in Figure 1, the alarm outputs are used
to control an LED. For the LED to light up when the alarm is on
or active, the alarm output must be low, so the alarm polarity
bit should be set to 1, Active_Low.

5.0 Creating Two High or Two Low Alarms

The Alarm Polarity bits also give the user the option to create
two high alarms or two low alarms.

Consider an application requiring two high alarms.
Conventionally, if the Alarm_Low Polarity is configured as
Active High, then the Alarm_Low output will become active
(goes high) when the humidity falls lower than the humidity
value represented in the Alarm_Low_On register and
becomes inactive (goes low) when the humidity rises above
the humidity value represented in the Alarm_Low_Off register.

Similarly, if the Alarm_High Polarity is configured as Active
High, then the Alarm_High output will become active (goes
high) when the humidity rises above the humidity value
represented in the Alarm_High_On register and becomes
inactive (goes low) when the humidity falls below above the
humidity value represented in the Alarm_High_Off register (see
Figure 5).

2 Honeywell Sensing and Control

Using Alarms on the Honeywell HumidIcon™ Digital
Humidity/Temperature Sensors: HIH-6130/6131 Series

Alarm_High_Off

Alarm_High_On

Alarm_Low_On

Alarm_Low_Off

Humidity

Time

Alarm_High Output = 1

Alarm_High Output = 0

Alarm_Low Output = 1

Alarm_Low Output = 0

Alarm_Low Output = 0
Alarm_High Output = 0

Alarm_High_Off

Alarm_High_On

Alarm_Low_On

Alarm_Low_Off

Humidity

Time

Alarm_High Output = 1

Alarm_High Output = 0

Alarm_Low Output = 0

Alarm_Low Output = 1

Alarm_Low Output = 1
Alarm_High Output = 0

EEPROM

Address

Default

Name

Description

0x00 to 0x15

N/A

reserved

do not change;
must be left at
factory settings;
locked EEPROM
locations

0x16

0x0000

reserved

do not change;
must be left at
factory settings

0x17

0x0000

reserved

do not change;
must be left at
factory settings

0x18

0x3FFF

Alarm_High_On

high alarm on trip
point

0x19

0x3FFF

Alarm_High_Off

high alarm off trip
point

0x1A

0x0000

Alarm_Low_On

low alarm on trip
point

0x1B

0x0000

Alarm_Low_Off

low alarm off trip
point

0x1C

0x0027

Cust_Config

Customer
Configuration
Register (see
Section 4.0)

0x1D

0x0000

reserved

do not change;
must be left at
factory settings

0x1E

0xYYYY

(Y=data)

Cust_ID2

customer ID word;
for use by customer

0x1F

0xYYYY

(Y=data)

Cust_ID3

customer ID word;
for use by customer

Figure 5. Alarm Outputs with Active High Polarity

If the polarity of the Alarm_Low output is changed to Active
Low then the Alarm_Low output will be high when the humidity
is above the humidity value stored in the Alarm_Low_Off
register and low when the humidity is less than humidity value
in the Alarm_Low_On register (see Figure 6).

Figure 6. Alarm Outputs with Active Low Polarity

6.0 Disabling Alarms

If an application does not require the use of alarms, then the
alarms may be disabled by setting registers Alarm_High_On
and Alarm_High_Off to their maximum value (0x3FFF) and
registers Alarm_Low_On and Alarm_Low_Off to their minimum
value (0x0000). In this configuration the alarm outputs must be
left unconnected in the application.

7.0 Appendices

7.1 Appendix A. EEPROM Memory Map

Table 2 shows the EEPROM Memory Map.

Table 2. EEPROM Memory Map

By reversing the polarity of Alarm_Low, its output now behaves
in the same manner as Alarm_High, in other words, as a
second high alarm; however, the effect of the alarm registers
also reverses. The Alarm_Low_On register acts like the
Alarm_High_Off register, while the Alarm_Low_Off register
acts like the Alarm_High_On register.

The same steps can be done to create two low alarms.
Reverse the polarity of Alarm_High and the functions of the
Alarm_High_On and Alarm_High_Off registers will also switch.

7.2 Appendix B. Customer Configuration Register

The Customer Configuration Register (see Table 3) is located
at EEPROM address 0x1C. It can only be accessed using
Command Mode.

Honeywell Sensing and Control 3

Using Alarms on the Honeywell HumidIcon™ Digital
Humidity/Temperature Sensors: HIH-6130/6131 Series

Sensing and Control
Honeywell
1985 Douglas Drive North
Golden Valley, MN 55422

www.honeywell.com/sensing

009060-3-EN
June 2012
Copyright © 2012 Honeywell International Inc. All rights reserved.

Bit

Default

Name

Description

6:0

0101000

device ID

I2C slave address

8:7

00

Alarm_Low_Cfg

configures the Alarm Low
output pin.

Bit

Description

7 alarm polarity:

0 = Active_High, 1 = Active_Low

8 output configuration:

0 = Full_Push-Pull, 1 = Open_Drain

10:9

00

Alarm_High_Cfg

configures the Alarm
High output pin.

Bit

Description

9

alarm polarity:
0 = Active_High, 1 = Active_Low

10

output configuration:
0 = Full_Push-Pull, 1 = Open_Drain

11 0 reserved

do not change; must be left at factory setting

12 0 reserved

do not change; must be left at factory setting

13 0 Fast Startup

sets the Command Window duration:
0 = 10 ms,1 = 3 ms

15:14

00

reserved

do not change; must be left at factory setting

PERSONAL INJURY

DO NOT USE these products as safety or emergency stop
devices or in any other application where failure of the
product could result in personal injury.

Failure to comply with these instructions could result in
death or serious injury.

MISUSE OF DOCUMENTATION

The information presented in this technical note is for

reference only. DO NOT USE this document as a product
installation guide.

Complete installation, operation, and maintenance

information is provided in the instructions supplied with
each product.

Failure to comply with these instructions could result in
death or serious injury.

Table 3. Customer Configuration Register

WARRANTY/REMEDY

Honeywell warrants goods of its manufacture as being free of
defective materials and faulty workmanship. Honeywell’s
standard product warranty applies unless agreed to otherwise
by Honeywell in writing; please refer to your order
acknowledgement or consult your local sales office for specific
warranty details. If warranted goods are returned to Honeywell
during the period of coverage, Honeywell will repair or replace,
at its option, without charge those items it finds defective. The

foregoing is buyer’s sole remedy and is in lieu of all other

warranties, expressed or implied, including those of
merchantability and fitness for a particular purpose. In no
event shall Honeywell be liable for consequential, special,
or indirect damages.

While we provide application assistance personally, through
our literature and the Honeywell web site, it is up to the
customer to determine the suitability of the product in the
application.

Specifications may change without notice. The information we
supply is believed to be accurate and reliable as of this printing.
However, we assume no responsibility for its use.

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of sales offices, representatives and distributors. For
application assistance, current specifications, pricing or name
of the nearest Authorized Distributor, contact your local sales
office or:

E-mail: [email protected]
Internet: www.honeywell.com/sensing

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