Honeywell HIH-6130 Series Instruction Manual

Technical Note
Using Alarms on the Honeywell HumidIcon™ Digital
Humidity/Temperature Sensors: HIH-6130/6131 Series
Sensing and Control
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:
Alarm functionality
How to combine alarms
Configuration options
How do disable alarms
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
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
83
4
5
6
1
2
7
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
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
83
4
5
6
1
2
7
GND
12 V 12 V
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):
Alarm_High_On
Alarm_High_Off
Alarm_Low_On
Alarm_Low_Off
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
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”.)
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.
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
2Honeywell Sensing and Control
The contents of the alarm registers correspond to humidity as
follows:
Humidity (%RH) = RegisterContents
(214 - 1) x 100%
Thus, 0 %RH = 0x0000 and 100 %RH = 0x3FFF or 16383.
For example, to enable the Alarm_High output at humidity
above 80 %RH:
Alarm_High_On =
80 %RH
100% x (214 - 1) = 13107 or 0 x 3333
Similarly, to enable the Alarm_Low output at humidity below
10 %RH:
Alarm_Low_On =10 %RH
100% x (214 - 1) = 1638 or 0 x 0666
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
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
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
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
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).

Using Alarms on the Honeywell HumidIcon™ Digital
Humidity/Temperature Sensors: HIH-6130/6131 Series
Honeywell Sensing and Control 3
Figure 5. Alarm Outputs with Active High Polarity
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
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
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
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.
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
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
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.

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.
Table 3. Customer Configuration Register
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
WARNING
PERSONAL INJURY
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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.
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