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TECHNICAL REFERENCE
I2C Protocol Implementation
HMM105 Humidity Module
M211638EN-A
Page 2
PUBLISHED BY
Vaisala Oyj
Street address: Vanha Nurmijärventie 21, FI-01670 Vantaa, Finland
Mailing address: P.O. Box 26, FI-00421 Helsinki, Finland
Phone: +358 9 8949 1
Fax: +358 9 8949 2227
Visit our Internet pages at www.vaisala.com.
© Vaisala 2014
No part of this manual may be reproduced, published or publicly displayed in any form
or by any means, electronic or mechanical (including photocopying), nor may its
contents be modified, translated, adapted, sold or disclosed to a third party without prior
written permission of the copyright holder. Translated manuals and translated portions
of multilingual documents are based on the original English versions. In ambiguous
cases, the English versions are applicable, not the translations.
The contents of this manual are subject to change without prior notice.
This manual does not create any legally binding obligations for Vaisala towards
customers or end users. All legally binding obligations and agreements are included
exclusively in the applicable supply contract or the General Conditions of Sale and
General Conditions of Service of Vaisala.
Page 3
_________________________________________________________________________________
Table of Contents
CHAPTER 1
GENERAL INFORMATION ............................................................................ 2
About This Manual ................................................................... 2
Version Information ................................................................. 2
Related Manuals ....................................................................... 2
CHAPTER 2
I2C INTERFACE ............................................................................................. 3
Overview ................................................................................... 3
Physical Interface .................................................................. 3
Communication Parameters .................................................. 4
Addressing ............................................................................ 4
Communication Flow ............................................................... 5
HMM105 State Machine ........................................................ 6
Examples of Communication Flow ........................................ 7
Timing .................................................................................... 9
Status Byte ............................................................................ 9
Checksum ............................................................................. 9
Status Word......................................................................... 10
Commands .............................................................................. 11
Get_Interface_Version ........................................................ 11
Get_Parameter .................................................................... 12
Example: Read RH Measurement Result ...................... 13
Set_Parameter .................................................................... 14
Example: Set Compensation Pressure .......................... 15
Get_Parameter_Info ............................................................ 16
Adjust .................................................................................. 17
Adjusting Measurement......................................................... 18
One Point Adjustment ......................................................... 18
Two Point Adjustment ......................................................... 18
Data Registers ........................................................................ 19
Data Formats .......................................................................... 19
Register Table ..................................................................... 20
VAISALA _____________________________________________________________________ 1
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Technical Reference _________________________________________________________________
Manual Code
Description
M211638EN-A
May 2014. First version.
Manual Code
Manual Name
M211637EN
HMM105 Quick Guide
CHAPTER 1
GENERAL INFORMATION
About This Manual
This manual describes the I2C interface implementation of the
Vaisala HUMICAP® Humidity Module HMM105.
Version Information
Table 1 Manual Revisions
Related Manuals
Table 2 Related Manuals
2 _________________________________________________________________ M211638EN-A
Page 5
Chapter 2 _______________________________________________________________ I2C Interface
3.3 V
5.0 V
SD
A
SCL
GND
2 x 10 kΩ
2 x 10 kΩ
uP
Bu
ffer and
level shi
ft
CHAPTER 2
I2C INTERFACE
Overview
HMM105 has an inter-integrated circuit (I2C) interface for interfacing
with the incubator’s control computer. HMM105 implements I2C slave
functionality, with the incubator’s computer acting as the master. The
interface can be used to read measurement values and status information,
set operation parameters, and make adjustments.
Physical Interface
The physical interface is a non-isolated 3-wire interface. Wires are SDA,
SCL and ground. SDA and SCL lines are buffered. Ground is shared
with power supply. There are small pull-up resistors for SCL and SDA.
Maximum cable length should not exceed 5 m and maximum capacitance
between communication lines and ground should not exceed 500 pF.
1405-072
Figure 1 Hardware Schematic
The physical connector is a Molex 87832-1007, 2 mm pitch shrouded
pin header with a locking window. It is marked X6 on the component
board. See Table 3 on page 4.
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Connector Pinout
Pin #
Function
6, 8
Supply voltage input
10 ... 35 VDC or 24 VAC
5, 7
Ground
1, 3
5 V I2C bus SDA
2, 4
5 V I2C bus SCL
0 1 0 1 1 1 1
R/W
Device type
Sub-address
Read/write bit
(LSB)
0 0 1 0 1 1 1 1 MSB
Device type
Sub-address
24
6810
1
3579
Table 3 HMM105 Signal and Power Connector X6
9, 10 Not connected
Communication Parameters
HMM105 supports a maximum clock speed of 50 kHz. Protocol bits are
sent most significant bit (MSB) first. Parameter bytes are sent using little
endian order.
Addressing
HMM105 uses 7-bit addressing. The address consists of:
- 4-bit device type identifier part (default “0101” for HMM105)
- 3-bit sub address (default “111”)
The full 7-bit default address is “0101111” (2Fh). In I2C communication,
the address should be provided by the master in the standard way after
the I2C start condition, with the read/write bit as the least significant bit
(LSB).
Table 4 HMM105 I2C Address
The I2C implementation of the HMM105 also includes the address inside
the message frame. The purpose of this is to make the I2C
implementation easier, since the I2C address can be lost by the I2C
hardware. This address is provided without the read/write bit, with zero
as the most significant bit (MSB).
Table 5 HMM105 Device Address
NOTE
4 _________________________________________________________________ M211638EN-A
Make sure there are no addressing conflicts if other I2C devices are put
on the same bus. The HMM105 address can be changed, see Table 32 on
page 20.
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Chapter 2 _______________________________________________________________ I2C Interface
This ACK/NACK refers to message level acknowlegde. I
includes separate byte level acknowledge.
Message Segment
Length
Content
Start
I2C start condition.
I2C address
1 byte
See Table 4 on page 4.
Command
1 byte
Identifier of command.
Device address
1 byte
See Table 5 on page 4.
Frame length
1 byte
Length of invoke message in bytes
Minimum invoke frame length is 5 bytes.
Data
Variable length
Content and length depending on the
contains no data in the invoke message.
Checksum
2 bytes
See section Checksum on page 9.
Stop
I2C stop condition
Message Segment
Length
Content
Start
I2C start condition.
I2C address
1 byte
See Table 4 on page 4.
Status
1 byte
See section Status Byte on page 9.
Command
1 byte
Identifier of the command that was used
valid invoke), command code is FFh.
Device address
1 byte
See Table 5 on page 4.
Frame length
1 byte
Length of the response message in
length is 6 bytes.
Data
Variable length
Content and length depending on the
command.
Checksum
2 bytes
See section Checksum on page 9.
Stop
I2C stop condition
Communication Flow
Basic communication flow always includes I2C write and read
commands. First the master writes a command to the slave device, and
then the master reads the results of that command from the slave.
When the master reads data from the slave, there is an ACK/NACK-bit in
the status byte that informs the master whether or not communication
was success. ACK is defined as zero and NACK is defined as one in the
logical level.
2
NOTE
Command messages sent by the master are called invokes. Replies sent
by the slave are called responses. Note that also responses include the
device address.
Table 6 Invoke Message in HMM105 I2C Interface
C protocol
(excluding I2C address, including CRC).
command. May be left out if command
Table 7 Response Message in HMM105 I2C Interface
in the invoke that the slave is
responding to. If slave is in idle state (no
bytes (excluding I2C address, including
CRC). The minimum response frame
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Wait
Response
Idle
Valid Invoke
Valid Invoke
Response
NACK
Response
ACK + data
Bad Invoke
Bad Invoke
Response
NACK
HMM105 State Machine
The main and initial state of the HMM105 is Idle, and it will change to
WaitResponse state only when a valid invoke is received. In
WaitResponse state HMM105 expects to see an I2C read operation. After
seeing a read operation the HMM105 outputs its response with
ACK/NACK and status signals.
If HMM105 is in WaitResponse state and the master sends a new invoke,
the old response belonging to the old invoke will be lost. When the
master sends the next I2C read command, the HMM105 sends it the
response to the latest invoke.
If HMM105 is in Idle state and I2C read is sent, HMM105 responds with
a NACK-signal. This tells the master that the data which the master may
have received in same I2C read is not valid.
If the HMM105 receives an invalid invoke, it goes to the Idle state. An
invoke message can be invalid because of an unknown command,
erroneous CRC, or invalid message length.
.
Figure 2 HMM105 State Machine
1405-073
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Chapter 2 _______________________________________________________________ I2C Interface
Master
Slave
Get_Parameter,RH_ID
I2C write
Get_Parameter,RH_ID,54.32, ACK
I2C read
Master
Slave
Set_Parameter,Pressure_ID,1013.25
I2C Write
Set_Parameter,Pressure_ID,ACK
I2C Read
Examples of Communication Flow
The basic data transfer communication flows are presented in the
following figures. Each arrow represents an I2C read or write operation
The examples are simplified presentations. For actual message content,
see section Commandson page 11.
For example, Figure 3 below shows the following message sequence:
1. The master invokes the Get_Parameter command to read the RH
parameter using an I2C write operation. This command prepares the
slave to wait for a read operation from the master.
2. The master begins an I2C read operation to read the results of the
Get_Parameter RH command. The slave sends the requested RH
result and an ACK signal to the master.
1401-020
Figure 3 Get_Parameter with ACK
1401-032
Figure 4 Set_Parameter with ACK
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Master
Slave
Get_Parameter,RH_ID
I2C Write
Get_Parameter,RH_ID,nan,NACK
I2C Read
Master
Slave
Get_Parameter,RH_
ID
I2C Write
Get_
Parameter
, RH_ID,66
.55,
Alarm bit = 1, ACK
I2C Read
Get_Parameter,Status_ID
I2C Write
Get
_Parameter,Status_ID,statusword,ACK
I2C Read
1401-022
Figure 5 Get_Parameter with NACK
1401-021
Figure 6 Get_Parameter with Alarm
NOTE
8 _________________________________________________________________ M211638EN-A
Alarm can be any of the state bits in status byte.
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Chapter 2 _______________________________________________________________ I2C Interface
Operation
Minimum delay
Normal delay between invoke and response
10 ms
Delay when write to non-volatile memory
300 ms
Bit#
Description
0
ACK/NACK
1
Critical error
2
Error
3
Warning
4
Status
5 6 7
Timing
The minimum time delay that the master must wait between the invoke
and response messages depends on the operation. If the operation
includes a write to the non-volatile memory, it takes more time than other
operations.
Table 8 Timing
Status Byte
The status byte gives the master device information about the slave
device’s state, and information about the communication status with the
ACK/NACK bit.
The status byte has bits for signaling Status, Warning, Error and Critical
error statuses. These bits are cleared when the status word is read. Bits
are set when the corresponding status or error state changes in the slave
device.
Table 9 Status Byte
Checksum
HMM105 uses a CRC16-CCITT checksum in its protocol frame. CCITT
(x.25) polynomial is X16+X12+X5+1 = 11021h. Initial value is 0000h and
the final value is XORed with FFFFh. The checksum uses a bit reversed
algorithm.
When the invoke message is received, the checksum is calculated using
bytes from the command byte to the last byte of the data field. The
checksum needs to be valid before data can be accepted. If the checksum
is not valid, the message is rejected and the internal state of the GMP231
is set to Idle.
When the response message is transmitted, the checksum is calculated
using bytes from the status byte to the last byte of the data field.
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Bit#
Type
Purpose
0
Critical Error
1 Critical Error
Parameter memory corrupted
2
Critical Error
Parameter read failed
3
Critical Error
Parameter write failed
4
Error
5 Error
RH measurement error
6
Error
T measurement error
7
Error
8 Error
9 Error
10
Error
11
Error
12
Error
13
Error
14
Warning
15
Warning
16
Warning
17
Warning
18
Warning
19
Status
20
Status
21
Status
22
Status
23
Status
24
Status
25
Status
26
Status
27
Status
28
Status
29
Status
30
Status
31
Status
Status Word
Status word is used to monitor the status of the HMM105 device. It can
be read in the same way as any other slave parameter. Status word is used
as 32-bit long bit field. Each bit represents a state of some error or other
essential status.
Changes in status word bits can be monitored by reading the status byte.
See section Status Byte on page 9.
Table 10 Status Word Content
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Chapter 2 _______________________________________________________________ I2C Interface
Message Segment
Length
Content
I2C address
1 byte
I2C address (write)
Command ID
1 byte
Always 80h
Device address
1 byte
See Table 5 on page 4
Frame length
1 byte
Always 05h
Checksum
2 bytes
See section Checksum on page 9
Message Segment
Length
Content
I2C address
1 byte
I2C address (read)
Status
1 byte
See section Status Byte on page 9
Command ID
1 byte
Always 80h
Device address
1 byte
See Table 5 on page 4
Frame length
1 byte
Always 0Ah
Data
1 byte
Device version
1 byte
Protocol frame version
1 byte
Command set version
1 byte
Parameter set version
Checksum
2 bytes
See section Checksum on page 9
Commands
Get_Interface_Version
The Get_Interface_Version command (ID 80h) reads the interface
version information. Recommended for verifying version compatibility
before reading or writing parameters.
Table 11 Get_Interface_Version Invoke Message
Table 12 Get_Interface_Version Response Message
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Message Segment
Length
Content
I2C address
1 byte
I2C address (write)
Command ID
1 byte
Always 81h
Device address
1 byte
See Table 5 on page 4
Frame length
1 byte
Always 06h
Data
1 byte
ID of parameter to be read
Checksum
2 bytes
See section Checksum on page 9
Message Segment
Length
Content
I2C address
1 byte
I2C address (read)
Status
1 byte
See section Status Byte on page 9. If
NACK bit is set in the status byte.
Command ID
1 byte
Always 81h
Device address
1 byte
See Table 5 on page 4
Frame length
1 byte
Varies according to data length,
07h ... 39h.
Data
1 byte
ID of parameter
1 ... 50 bytes
Value of parameter. If requested
bytes are left out of the response.
Checksum
2 bytes
See section Checksum on page 9
Get_Parameter
The Get_Parameter command (ID 81h) reads parameter values. You can
use it to read both measurement results and operational parameters. If the
number of bytes the master tries to read exceeds the message size, the
slave sends FFh bytes.
Table 13 Get_Parameter Invoke Message
Table 14 Get_Parameter Response Message
requested parameter ID was unknown,
parameter ID is unknown, these data
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Chapter 2 _______________________________________________________________ I2C Interface
Message Bytes (hex)
Content
2F
I2C address
81
Get_Parameter command
2F
Device address
06
Frame length
4F
RH Parameter ID
6A
CRC high
D4
CRC lo
Message Bytes (hex)
Content
2F
I2C address
00
Status byte (no errors, ACK)
81
Get_Parameter command
09
Device address
0B
Frame length
4F
RH Parameter ID
D4
RH value 14.43086624 %RH
E4
66
41
85
CRC high
6A
CRC lo
Example: Read RH Measurement Result
Table 15 Get_Parameter Invoke Message Example
Table 16 Get_Parameter Response Message Example
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Message Segment
Length
Content
I2C address
1 byte
I2C address (write)
Command ID
1 byte
Always 82h
Device address
1 byte
See Table 5 on page 4
Frame length
1 byte
Varies according to data length,
07h ... 38h.
Data
1 byte
Parameter ID
1 ... 50 bytes
Parameter value
Checksum
2 bytes
See section Checksum on page 9
Message Segment
Length
Content
I2C address
1 byte
I2C address (read)
Status
1 byte
See section Status Byte on page 9.
Command ID
1 byte
Always 82h
Device address
1 byte
See Table 5 on page 4
Frame length
1 byte
Always 08h.
Data
1 byte
Parameter ID
1 byte
Return code. See Table 19 below.
Checksum
2 bytes
See section Checksum on page 9
Code
Meaning
0
Ok 1 Unknown parameter ID
2
Not writeable parameter
3
Value field too long
4
Value field too short
5
Data value not accepted
Set_Parameter
The Set_Parameter command (ID 82h) writes parameter values to nonvolatile memory. You can use it to set the operational parameters of the
HMM105. Depending on the change, the functionality of the HMM105
may not change immediately.
The length of the invoke message varies depending on the data length.
The master must write as many bytes as indicated in the frame length of
the invoke message. If the master tries to write a longer or shorter
message, HMM105 rejects the message.
Table 17 Set_Parameter Invoke Message
Table 18 Set_Parameter Response Message
Table 19 Set_Parameter Return Codes
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Chapter 2 _______________________________________________________________ I2C Interface
Message Bytes (hex)
Content
2F
I2C address
82
Set_Parameter command
2F
Device address
0A
Frame length
40
Parameter ID of compensation pressure
00
Pressure 1000 hpa
00
7A
44
D8
CRC high
31
CRC lo
Message Bytes (hex)
Content
2F
I2C address
04
Status byte (error active, ACK)
82
Set_parameter command
2F
Device address
08
Frame length
40
Parameter ID of compensation pressure
00
Return code: Ok
D6
CRC high
5C
CRC lo
Example: Set Compensation Pressure
Table 20 Example Set_Parameter Invoke Message
Table 21 Example Set_Parameter Response Message
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Message Segment
Length
Content
I2C address
1 byte
I2C address (write)
Command ID
1 byte
Always 83h
Device address
1 byte
See Table 5 on page 4
Frame length
1 byte
Always 06h.
Data
1 byte
Parameter ID
Checksum
2 bytes
See section Checksum on page 9
Message Segment
Length
Content
I2C address
1 byte
I2C address (read)
Status
1 byte
See section Status Byte on page 9.
Command ID
1 byte
Always 83h
Device address
1 byte
See Table 5 on page 4
Frame length
1 byte
Always 12h.
Data
1 byte
Parameter ID
1 byte
Parameter datatype. See Table 24
below.
1 byte
Parameter length in bytes.
1 byte
Parameter persistence. Describes if the
Table 25 below.
8 bytes
Parameter name. If the name is shorter
00h.
Checksum
2 bytes
See section Checksum on page 9
Code
Meaning
0
Unknown parameter ID
1
Byte
2
Integer (16-bit)
3
Unsigned Integer (16–bit)
4
Float (32-bit)
5
String
Code
Meaning
0
Void
1
Volatile
2
Non volatile
Get_Parameter_Info
The Get_Parameter_Info command (ID 83h) reads the properties of a
single parameter from the HMM105. The command is useful for adapting
to parameters that have been added in a new software version. If the
requested parameter ID is not valid, data type Unknown Parameter ID
is returned.
Table 22 Get_Parameter_Info Invoke Message
Table 23 Get_Parameter_Info Response Message
parameter value is volatile (lost at reset)
or non-volatile (survives reset). See
than 8 bytes, extra bytes are filled with
Table 24 Parameter Data Types
Table 25 Parameter Persistence
16 ________________________________________________________________ M211638EN-A
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Chapter 2 _______________________________________________________________ I2C Interface
Message Segment
Length
Content
I2C address
1 byte
I2C address (write)
Command ID
1 byte
Always 84h
Device address
1 byte
See Table 5 on page 4
Frame length
1 byte
Varies according to data length,
07h ... 0Bh.
Data
1 byte
Adjustment subcommand.
See Table 28 below.
1 byte
Parameter to be adjusted.
See Table 29 below.
4 bytes
Value of parameter. Used only with
subcommands 2 and 3.
Checksum
2 bytes
See section Checksum on page 9
Message Segment
Length
Content
I2C address
1 byte
I2C address (read)
Status
1 byte
See section Status Byte on page 9.
Command ID
1 byte
Always 84h
Device address
1 byte
See Table 5 on page 4
Frame length
1 byte
Always 07h.
Data
1 byte
Return code. See Table 30 on page 18.
Checksum
2 bytes
See section Checksum on page 9
Code
Adjustment operation
0
Start 1 point adjustment
1
Start 2 point adjustment
2
Record measured point 1, reference value is given in parameter
3
Record measured point 2, reference value is given in parameter
4
Cancel adjustment (previous adjustment is reverted)
5
End (adjustment is saved and new values are taken in use)
6
Revert to factory calibration (clear user adjustment)
Code
Purpose
0
All parameters (valid with revert to factory calibration)
1
Not used
2 T 3
Not used
4
RH
Adjust
The Adjust command (ID 84h) controls the user adjustment sequence of
the HMM105.
Table 26 Adjust Invoke Message
Table 27 Adjust Response Message
Table 28 Adjustment Subcommands
Table 29 Adjustment Parameters
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Code
Meaning
0
Ok 1 Function not supported
2
Sequence error
3
Recorded-Reference difference too large
4
2-point adjustment: Points too close
Table 30 Adjustment Return Codes
Adjusting Measurement
HMM105 can be adjusted while it remains installed in an incubator.
Create the reference environment inside the chamber, and use the Adjust
command to perform the adjustment sequence.
Adjustment can fail for a number of reasons. Refer to the list of return
codes for the Adjust command in Table 30 above.
One Point Adjustment
To perform a one point adjustment of relative humidity (RH) or
temperature (T), you must perform the following sequence:
1. Using the Adjust command, start 1 point adjustment for the
chosen parameter.
2. Place the sensor in the reference environment and wait until the
measurement has stabilized.
3. Using the Adjust command, record the measured point and give
the reference value.
4. Use the Adjust command to end the adjustment.
Two Point Adjustment
To perform a two point adjustment of relative humidity (RH) or
temperature (T), you must perform the following sequence:
1. Using the Adjust command, start 2 point adjustment.
2. Place the sensor in the low end reference and wait until the
measurement has stabilized.
3. Using the Adjust command, record the first measured point and
give the first reference value.
4. Place the sensor in the high end reference and wait until the
5. Using the Adjust command, record the second measured point and
6. Use the Adjust command to end the adjustment.
18 ________________________________________________________________ M211638EN-A
measurement has stabilized.
give the second reference value.
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Chapter 2 _______________________________________________________________ I2C Interface
Data type name
Size (Bytes)
Other
Byte
1
Value range 0...255
Integer
2
Value range -32768...32767
Unsigned integer
2
Value range 0…65535
Long integer
4
Value range
−2,147,483,648…2,147,483,647
Unsigned long integer
4
Value range 0…4,294,967,295
Float
4
According to IEEE-754. NaN
is available
String
Max. 50
All characters accepted
(00h…FFh)
Maximum string size refers to
Actual reserved storage space for each parameter can be seen
on page 20
Integers and floating point numbers are sent LSB first.
Data Registers
The register table describes all available parameters and their properties.
The properties are: parameter meaning, ID, name, data type, length and
persistence. Persistence defines if the parameter is saved in EEPROM
(non-volatile memory) or in RAM. Make sure not to write excessively to
the EEPROM, as it has a maximum lifetime of approximately 30000
cycles.
Data Formats
Table 31 Data Formats
NOTE
NOTE
(7FC00000) is returned if no value
maximum communication buffer size.
in Table 32
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Meaning
Name
ID
Size
(bytes)
Type
Read/
Write
Persistent
Other
Factory information
Device Address
ADDR
0 1 Byte
R
Yes
Normally 0x2F.
1 ... 7.
Device serial number
SNUM
1
12
Str R Yes
Example: A1234567
Sensor number
SSNUM
2
12
Str R Yes
Example: B1234567
Component board
number
CBNUM
3
12
Str R Yes
Example: C1234567
Software version number
VERS
4
12
Str R Yes
Example: 1.2.3.4567
Factory calibration date
DDMMYYYY
CDATE
6 4 Uint R Yes
Example: 19052014
Factory calibration info
CTEXT
7
19
Str R Yes
Example: "CAL INFO"
General parameters and variables
Device status word
STATUS
8 4 Str R No
See section Status
Word on page 10.
Unit representation
selection
UNITS
10 2 Byte
R/W
Yes
0 = Metric units
1 = Nonmetric units
RH result
RH
79 4 Float
R
No
%RH
Temperature result
T
65 4 Float
R
No
degrees of
(see UNITS)
Dew/Frost point Tdf
TDF
88 4 Float
R
No
degrees of
(see UNITS)
Ambient pressure in hPa
P_AMB
64 4 Float
R/W
Yes
Ambient pressure in
result.
RH Gain
RH_G
96 4 Float
R/W
Yes
RH gain
RH Offset
RH_O
97 4 Float
R/W
Yes
RH offset
Temperature Gain
T_G
94 4 Float
R/W
Yes
Temperature gain
adjustment
Temperature Offset
T_O
95 4 Float
R/W
Yes
Temperature offset
adjustment
Temperature reference
T_RP1
90 4 Float
R/W
Yes
Temperature
calibration command.
Temperature reference
T_RP2
91 4 Float
R/W
Yes
Temperature
calibration command.
RH reference point 1
RH_RP1
92 4 Float
R/W
Yes
RH adjustment
command.
RH reference point 2
RH_RP2
93 4 Float
R/W
Yes
RH adjustment
command.
Register Table
Table 32 HMM105 Register Table
Only 3 LSBs are
changeable. Address
range is therefore
point 1
point 2
celsius/fahrenheit
celsius/fahrenheit
hPa. Used for RH
adjustment reference
point 1. Write ref 1
here when using the
adjustment reference
point 2. Write ref 2
here when using the
reference point 1.
Write ref 1 here when
using the calibration
20 ________________________________________________________________ M211638EN-A
reference point 2.
Write ref 2 here when
using the calibration
Page 23
*M211638EN*
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