PNI TCM 2.6 User Manual

User Guide

User Guide

TCM2.5 & TCM2.6

© Copyright PNI Sensor Corporation 2005
All Rights Reserved. Reproduction, adaptation, or translation without prior written permission is prohibited, except

as allowed under copyright laws.
Revised July 2013. For most recent version visit our website at www.pnicorp.com
PNI Sensor Corporation

2331 Circadian Way
Santa Rosa, CA 95407 USA
Tel: [phone]
Fax: [phone]

Warranty and Limitation of Liability. PNI Sensor Corporation ("PNI") manufactures its TCM products (“Products”)
from parts and components that are new or equivalent to new in performance. PNI warrants that each Product to be
delivered hereunder, if properly used, will, for one year following the date of shipment unless a different warranty

time period for such Product is specified: (i) in PNI’s Price List in effect at time of order acceptance; or (ii) on PNI’s

web site (www.pnicorp.com) at time of order acceptance, be free from defects in material and workmanship and will

operate in accordance with PNI’s published specifications and documentation for the Product in effect at time of

order. PNI will make no changes to the specifications or manufacturing processes that affect form, fit, or function of
the Product without written notice to the OEM, however, PNI may at any time, without such notice, make minor
changes to specifications or manufacturing processes that do not affect the form, fit, or function of the Product. This
warranty will be void if the Products’ serial number, or other identification marks have been defaced, damaged, or
removed. This warranty does not cover wear and tear due to normal use, or damage to the Product as the result of
improper usage, neglect of care, alteration, accident, or unauthorized repair.

THE ABOVE WARRANTY IS IN LIEU OF ANY OTHER WARRANTY, WHETHER EXPRESS, IMPLIED, OR
STATUTORY, INCLUDING, BUT NOT LIMITED TO, ANY WARRANTY OF MERCHANTABILITY,
FITNESS FOR ANY PARTICULAR PURPOSE, OR ANY WARRANTY OTHERWISE ARISING OUT OF ANY
PROPOSAL, SPECIFICATION, OR SAMPLE. PNI NEITHER ASSUMES NOR AUTHORIZES ANY PERSON
TO ASSUME FOR IT ANY OTHER LIABILITY.

If any Product furnished hereunder fails to conform to the above warranty, OEM’s sole and exclusive remedy and
PNI’s sole and exclusive liability will be, at PNI’s option, to repair, replace, or credit OEM’s account with an

amount equal to the price paid for any such Product which fails during the applicable warranty period provided that
(i) OEM promptly notifies PNI in writing that such Product is defective and furnishes an explanation of the

deficiency; (ii) such Product is returned to PNI’s service facility at OEM’s risk and expense; and (iii) PNI is satisfied

that claimed deficiencies exist and were not caused by accident, misuse, neglect, alteration, repair, improper
installation, or improper testing. If a Product is defective, transportation charges for the return of the Product to
OEM within the United States and Canada will be paid by PNI. For all other locations, the warranty excludes all
costs of shipping, customs clearance, and other related charges. PNI will have a reasonable time to make repairs or

to replace the Product or to credit OEM’s account. PNI warrants any such repaired or replacement Product to be

free from defects in material and workmanship on the same terms as the Product originally purchased.
Except for the breach of warranty remedies set forth herein, or for personal injury, PNI shall have no liability for any

indirect or speculative damages (including, but not limited to, consequential, incidental, punitive and special
damages) relating to the use of or inability to use this Product, whether arising out of contract, negligence, tort, or
under any warranty theory, or for infringement of any other party’s intellectual property rights, irrespective of
whether PNI had advance notice of the possibility of any such damages, including, but not limited to, loss of use,
revenue or profit. In no event shall PNI’s total liability for all claims regarding a Product exceed the price paid for
the Product. PNI neither assumes nor authorizes any person to assume for it any other liabilities.

Some states and provinces do not allow limitations on how long an implied warranty lasts or the exclusion or
limitation of incidental or consequential damages, so the above limitations or exclusions may not apply to you. This
warranty gives you specific legal rights and you may have other rights that vary by state or province.

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 2 of 49

About the TCM2.5/2.6

Thank you for purchasing the TCM2.5/2.6. The TCM2.5 has been designed as a drop-in

replacement for PNI Corporation’s TCM2 family of products. The TCM2.5 uses the same board size,

interface connector, and RS-232 protocol as the TCM2 modules to allow for ease of integration with
existing systems. The TCM2.6 has all the features of the TCM2.5, but is about half the size and
weight and has an extended temperature range.

The TCM2.5/2.6 are the choice for existing applications that require compatibility with PNI
Corporation’s TCM2 family of products.

The TCM2.5/2.6 integrates 3-axis magnetic field sensing, 2-axis tilt sensing, and compass heading
into a single module. Advantages include compatibility with existing systems, low power
consumption, large signal noise immunity under all conditions, and a large magnetic field
measurement range.

The TCM2.5/2.6 combines PNI Corporation’s patented Magneto-Inductive (MI) sensors and
measurement circuit technology with a MEMS accelerometer for unparalleled cost effectiveness
and performance. The MI sensor changes inductance by 100% over its field measurement range.
This variable inductance property is used in a cost and space efficient ASIC (PNI 11096) which
incorporates a temperature and noise stabilized oscillator/counter circuit which is inherently free
from offset drift.

The TCM2.5/2.6’s advantages make it suitable for many applications, including:

Remote terrestrial antenna direction indicators

Side-scan sonar

ROV, AUV control

Survey equipment
Robotics systems
Vehicle detection

With its many potential applications, the TCM2.5/2.6 provides a command set designed with flexibil­ity and adaptability in mind. Many parameters are user-programmable, including reporting units, a
wide range of sampling configurations, output damping, and more. We hope the TCM2.5/2.6 will
help you to achieve the greatest performance from your target system. Thank you for selecting the
TCM2.5/2.6.

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 3 of 49

Installation

PIN

Wire Color

TCM2.5 PIN Description

PIN

Wire Color

TCM2.6 PIN Description

1

Orange

Vsupply (5 V regulated)

1

Black

Power Ground

2

Red

Vsupply (6 to 18 V unregulated)

2

Gray

NC

3

Black

Power Ground

3

Green

RS232 Ground

4

Blue

RxD (RS-232) -5 to 5V

4

Orange

NC 5 Yellow

TxD (RS-232) -5 to 5V or -12 to 12V

5

Violet

NC 6 White

RTS, Wake from Sleep

6

Brown

NC

7

Green

Data Ground

7

Yellow

TxD

8

Brown

NC 8

Blue

RxD

9

Purple

NC 9

Red

5 VDC

10

Gray

Data Ground

Parameter

Model

PIN

Minimum

Maximum

Units

Supply Voltage – 5V Regulated

TCM2.5

1

-0.3

+10

VDC

TCM2.6

9

-0.3

+10

VDC

Supply Voltage – 6 to 18 V Unregulated

TCM2.5

2

-30

+30

VDC

This section describes how to configure, program, and control the TCM2.5/2.6 in your host system.
To install the TCM2.5/2.6 into your system, follow these steps:

Make electrical connections to the TCM2.5/2.6
Evaluate the TCM2.5/2.6 using the included TCM Studio Program
Choose a mounting location
Mechanically mount the TCM2.5/2.6
Perform user calibration

Electrical Connections

Included with the TCM2.5/2.6 Interface Kit is a cable to allow for the unit to be connected to your
host system. On one end of the cable is the connector needed to mate with the TCM2.5/2.6. The
cable’s wires are color coded as indicated below.

PNI also has a 6-foot cable with a DB9 connector attached. Contact PNI for purchasing information.

Table 1: TCM2.5/2.6 PIN Descriptions

CAUTION: Stresses beyond those listed above may cause permanent damage to the device. These are

stress ratings only. Operation of the device at these or other conditions beyond those indicated in the
operational sections of the specifications is not implied.

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 4 of 49

Absolute Maximum Ratings

RS-232 Serial Communication Interface

Parameters 8 data bits, 1 start bit, 1 stop bit, no parity, flow control none
Baud Rate 300 to 115200

Communicating with the TCM2.5/2.6

Once the TCM2.5/2.6 is powered up and the RS232 connection is made with one of the PC’s COM
ports, you may begin exchanging ASCII serial data with the TCM2.5/2.6. The most direct means is
to run any modem or terminal emulation software. Specify the COM port that you have the
TCM2.5/2.6 connected to and set the baud rate to the same baud rate of the TCM2.5/2.6. The
default baud rate for the TCM2.5/2.6 is 9600. Remember that the TCM2.5/2.6 does not echo
characters by default, so you may wish to select the echo output option in your terminal emulation
program or press <Ctrl> e on the keyboard.

TCM Studio – Evaluation Program

The TCM2.5/2.6 evaluation software communicates with the TCM2.5/2.6 through the COM port of
your PC. It provides an easy to use interface, so that instead of issuing command codes manually,
you can use buttons, check boxes, and dialog boxes. It reads the Binary responses of the
TCM2.5/2.6 output strings and formats its sensor data into labeled and easy-to-read data fields.
The program also includes the ability to log and save the outputs of the TCM2.5/2.6 to a file. All of
this is so that you may begin to learn the capabilities of the TCM2.5/2.6 while using the TCM Studio
program’s more friendly interface.

To install the TCM Studio program onto a Windows system:

1. Drag the “TCM Studio.exe” to the working directory of your computer.

2. Move the Quesa plug-in (Quesa.dll) into either the Windows System or System32 folder.
Quesa is the OpenGL rendering engine and the 3D Model of the TCMStudio will not run
without it.

For Windows 2000/NT copy to: /WinNT/System32 folder
For Windows XP copy to: /Windows/System32 folder

To Install the TCM Studio program onto a Mac OSX system:

1. Drag the “TCM Studio” to the working directory of your computer.

2. Move the Quesa plug-in (Quesa) to: /Library/CFMSupport

Hardware Setup:

1. Connect the unit to a serial port of the PC via the included cable. (A USB to Serial Adapter
can be used; Keyspan USA-19QW was tested.)

2. Supply power

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 5 of 49

[Connection Tab]

Initial Connection:

1. Select the serial port the unit is plugged into.

2. Select 9600 as the baud rate (default).

3. Click on the <Connect> button.

4. Once a connection is made the “Connected” light will turn green.

Change Baud Rate:

1. Select new baud rate for the module.

2. Select same baud rate for the computer.

3. Click on the <Connect> button.

Change Modules:

Once connection has been made, the TCM Studio will remember the last settings. Any
time a module is switched out, clicking on the <Connect> button once the new module is
attached will reestablish a connection as long as the module baud rate is the same as the
previous unit.

[Configuration Tab]

North Reference:

Magnetic: When the “Magnetic” radio button is selected, heading will be relative to Magnetic

North.

True: When the “True” radio button is selected, heading will be relative to True North. To use
North Heading in “True” mode, the declination needs to be set in the “Declination” window.

Options:

Use to select halting continuous output by sending a single “h” command.

Damping:

Enabled: Use to select if the filter (damping) is to be used
Time Const: Use to select 4, 8, 16, or 32 samples and apply the values to a filter prior to

calculating the heading. These filters allow for a much more stable reading, but can make the
acquisition of the data by the program slower. The default setting is 8.

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 6 of 49

Reading Units:

 Compass: Use to select either Degrees or Mils as the unit of measure.
 Inclinometer: Use to select either Degrees or Mils as the unit of measure.
 Temperature: Use to select either Celsius or Fahrenheit as the unit of measure.

Default:

This button will set the TCM2.5/2.6 module back to the factory default settings for the
parameters shown on the screen.

Note: This is similar, but with less parameters, to the factory command.

[Calibration Tab]

Start (stop)

Toggle button to begin and end calibration

Calibration Procedure:

1. Click on the <Start> button to begin.

2. Begin rotating the TCM2.5/2.6 in a circle while applying pitch and roll to the unit. The unit
will have the appearance of a “wobbling top” as it is moved through the calibration routine.

3. Turn the TCM2.5/2.6 around at least twice changing the pitch and roll as much as possible.

4. Each turn should take longer than 30 seconds. The turn does not need to be a perfect
circle. In the calibration mode, the TCM2.5/2.6 is trying to take as many different data
points as possible to determine the magnetic anomalies. The more pitch and roll points
you give it, the better it is able to determine the vertical magnetic fields. If possible, apply

as close to a ± 90˚ pitch and ± 90˚ roll. Doing so will improve the quality of the calibration.

Do not worry about exceeding the tilt range of the unit.

5. Once two complete rotations have been completed, click on the <Stop> button to finish the
calibration.

Score

The TCM2.5/2.6 provides feedback on calibration through the calibration score, which has

the following format: “...HnVnMn.n....”

The first two numbers in the calibration score, HnVn, respectively describe the quality of the

calibration for the horizontal component and vertical component of the host system’s local

magnetic field. Higher numbers reflect higher quality. The highest possible score is a “9”.
The factors that contribute to a good score for Hn and Vn are as follows:

 a good, magnetically quiet location was chosen for the user calibration

procedure.

 the magnetic environment is stable; there are no large sources of changing

fields.

 the calibration data points included changes in system heading and inclination

to allow for proper measurement of the horizontal and vertical field vectors.

 there are no significant soft-iron distortion effects.

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 7 of 49

The last number in the score, Mn.n, describes the magnitude of local field. Larger numbers
denote strong local fields. Small local fields are preferable, since less correction will be
necessary, and they utilize less of the magnetometers’ dynamic range. A magnitude score
greater than 30 indicates strong magnetic fields at the TCM2.5/2.6 location; you should
consider alternative mounting locations. Any score less than 10 is very good.

Note: The calibration score values mostly provide a qualitative estimation. For
example, a good score would be H9V9Mn.n. A poor score as anything less than
H9V9Mn.n. A poor V score generally indicates that you need to tilt more during the
calibration. A poor H score indicates you did not turn two full circles or that you

6. If the calibration is not sufficient then click on the <Start> button and begin the calibration
again.

Clear:

This button will clear the user calibration in the unit. Once selected, the unit will revert back to
its factory calibration.

turned too quickly.

[Test Tab]

Current Reading:

Once the <GO> button is selected the unit will begin outputting Heading, Pitch and Roll
information. Selecting the <Stop> button or changing tabs will halt the output of the unit.

3D Model:

The helicopter will follow the movement of the attached module and give a clear representation
of the module’s orientation.

[Data Logger Tab]

1. Select the data to log in the “Data” window.

2. Use Shift-Ctrl-Click and Ctrl-Click to select multiple items.

3. Click on the <GO> button to start logging; click the <STOP> button to stop logging.

4. Click on the <Export> button to save the data to a file.

5. Click on the <Clear> button to clear the data from the window.

[System Log Tab]

Export:

Select the <Export> button to save the system log to a file.

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 8 of 49

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 9 of 49

Where to install the TCM2.5/2.6

The TCM2.5/2.6’s magnetometers’ wide dynamic range and its sophisticated calibration algorithms

allow it to operate in many environments. For optimal performance however, you should mount the
TCM2.5/2.6 with the following considerations in mind:

The TCM2.5/2.6’s magnetometers should not saturate

The TCM2.5/2.6 can be calibrated for large static magnetic fields. However, each axis of

the TCM2.5/2.6’s magnetometers has a maximum dynamic range of ±80 µT (this can be

read using the TCM Studio with by going to the datalogger and selecting “Magnetometer

Output); if the total field exceeds this value for any axis, the TCM2.5/2.6 will not give
accurate heading information. When mounting the TCM2.5/2.6, consider the effect of any

sources of magnetic fields in the local environment that when added to the earth’s field may
saturate the TCM2.5/2.6’s sensors. For example, large masses of ferrous metals such as

transformers and vehicle chassis, large electric currents, permanent magnets such as
electric motors, and so on.

Locate the TCM2.5/2.6 away from local sources of changing magnetic fields

It is not possible to calibrate for changing magnetic anomalies. Thus, for greatest accuracy,
keep the TCM2.5/2.6 away from sources of local magnetic anomalies that will change with
time; for instance, electric equipment that will be turned on and off or nearby ferrous bodies
that will be changing positions. Make sure the TCM2.5/2.6 is not mounted close to cargo or
payload areas that may be loaded with large sources of local magnetic fields.

The TCM2.5/2.6 should be mounted in a physically stable location

Choose a location that is isolated from excessive shock, oscillation, and vibration.

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 10 of 49

Mechanically mounting the TCM2.5/2.6

Refer to the TCM2.5/2.6 Dimensional Specification later in this manual for the TCM2.5/2.6 board
dimensions and the orientation of the reference frame.

The TCM2.5/2.6 is factory calibrated with respect to the mounting holes, as shown below, thus it
must be aligned within the host system with respect to these mounting holes, not the board edges.

Figure 1: TCM2.5 Mounting Diagram

Figure 2: TCM2.6 Mounting Diagram

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 11 of 49

Using the TCM2.5/2.6

RS232 Data Output Word

The TCM2.5/2.6 sends an “output word” in ASCII across the RS232 serial link when issued the s?
(Single Output Word) command, or when in go (Continuous Sampling) mode. This data output
word may be configured by the user for the desired format and configuration. You may select either
NMEA 0183, or TCM2 standard output word formats, with the sdo= (Set RS-232 Output Word)
command.

NMEA 0183 Format

The TCM2.5/2.6 can be configured to conform to the NMEA (National Maritime Electronics
Association) 0183 specification, which describes a standard RS232 bus format for exchange of a
variety of navigation information (GPS, radar, compass, and so on). In the NMEA output format,
only compass heading information is available. Inclinometer, magnetometer, thermometer data and
the distortion detection warning are all unavailable.

$HCHDM,<compass>,M*checksum<cr><lf> !for magnetic heading

For example,
$HCHDM,182.3,M*checksum<cr><lf> !for magnetic heading = 182.3 °

The checksum value is the result of XOR’ing the ASCII bytes between the ‘$’ and ‘*’ characters.
This one byte value is reported in the output word by two ASCII characters representing two hex
digits, with the most significant nibble first. For example, “...*A3<cr><lf>” indicates that the
output word has a decimal checksum value of 163.

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 12 of 49

TCM2.5/2.6 Standard Output

The TCM2.5/2.6 standard output format may be configured to provide all of the sensor data
parameters available, or only those parameters required.

$C<compass>P<pitch>R<roll>X<Bx>Y<By>Z<Bz>T<temp>E<error
code>*checksum<cr><lf>

View the sections covering the commands: c? (Compass Update), m? (Magnetometer Update), i?
(Inclinometer Update), t? (Temperature Update) for detailed information regarding the character
formatting and resolution of the values for each of the data parameters in the output word.

Example

The TCM2.5/2.6 will return the following:

$C328.3P28.4R-12.4X55.11Y12.33Z-18.43T22.3E001*checksum<cr><lf>

under the following conditions:

compass heading = 328.3 ° (true or magnetic, depending on configuration)
pitch = 28.4 °
roll = -12.4 °
Bx = 55.11µT (x-component of magnetic field)
By = 12.33 µT (y-component of magnetic field)
Bz = -18.43 µT (z-component of magnetic field)
Temperature = 22.3 ° (F/C depending on configuration)
E001 = Distortion flag is raised–magnetic anomaly nearby

Any parameters not enabled are not included in the output word.
For example:

$C328.3T22.3*checksum<cr><lf> !for compass and thermometer information only.

The checksum value is computed and reported identically to that for the NMEA output format.

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 13 of 49

Command Syntax

Input Command

TCM2.5/2.6 Response

Valid parameter-setting commands

:<cr><lf>

Valid action command

varies according to command

Valid Parameter query commands

:<parameter>=<value><cr><lf>

Invalid, or unrecognized command

:E<code><cr><lf>

Valid sensor query command

varies according to command

The ‘:’ character signifies a successfully identified and executed command.

There are three types of commands you may issue to the TCM2.5/2.6:

User Configuration Parameter commands which set user-definable parameters.
Request for Data commands which query the TCM2.5/2.6 for data or for the stored value of

user-definable parameters.

Action commands which prompt the TCM2.5/2.6 to perform a specific action.

All commands must be followed with a <cr>, or <cr><lf>. The <lf> characters are ignored by the
TCM2.5/2.6, but are supported to allow compatibility with a variety of terminals.

Commands are case sensitive.

Programming Conventions

Set TCM2.5/2.6 user parameters: <parameter>=<value><cr>
Query TCM2.5/2.6 data (parameter or sensor values): <parameter>?<cr>
Action command: <command><cr>
Detailed descriptions of all commands are in the “Command List” and a command summary is

shown in “Command List Quick Reference”

Data Transmission

The TCM2.5/2.6 will transmit data across the RS-232 interface in response to input commands, and
will also transmit data output words automatically when placed in continuous output mode. The
response to the various commands is as follows:

Table 2: Input Command Responses

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 14 of 49

Error Codes

1st ASCII Character

Bit 3 (MSB)

EEPROM1 error

Bit 2

EEPROM2 error

Bit 1

Reserved for future use (always 0)

Bit 0 (LSB)

Reserved for future use (always 0)

2nd ASCII Character

Bit 3 (MSB)

Reserved for future use (always 0)

Bit 2

Command parameter invalid

Bit 1

Reserved for future use (always 0)

Bit 0 (LSB)

Command invalid or not supported on
current TCM

3rd ASCII Character

Bit 3 (MSB)

Reserved for future use (always 0)

Bit 2

Magnetometer out of range

Bit 1

Inclinometer out of range

Bit 0 (LSB)

Reserved for future use (always 0)

Error Code

Description

E002

Inclinometer out of range

E004

Magnetometer out of range

E006

Magnetometer out of range + Inclinometer out of range

E010

Command invalid or not available

E040

Command parameter invalid

E050

Command invalid or not available + Command parameter invalid

E400

EEPROM2 error

a

E800

EEPROM1 error

a

EC00

EEPROM2 error + EEPROM1 error

a

a. Indicates that the TCM2.5/2.6 EEPROM has been corrupted. Contact PNI for assistance.

Error codes are given in the output word immediately before the checksum output indicated by the
letter “E” followed by three ASCII characters representing hexadecimal digits (for example, ASCII F
equals hexadecimal value F, or decimal value 15). Each error condition corresponds to one bit
within one of the hexadecimal digits. When the error condition exists, that bit will be set equal to 1 in
the error code transmitted by the TCM2.5/2.6. The error conditions and their corresponding bit
locations are listed below. Refer to Table 4: Common Error Codes for a list of the most common
error codes.

Table 3: Bit Locations of Error Conditions

Table 4: Common Error Codes

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 15 of 49

Description of Error Conditions

Command Parameter Invalid – contains an invalid or out of range value.
Command invalid or not available on current model of TCM2 – is not recognized by the

TCM2.5/2.6. The syntax is incorrect, or you have entered a command which is not supported by
the TCM model you are using.

Inclinometer out of range – the inclinometer sensor is detecting an attitude that is outside of its
operational range of maximum pitch and roll. When this error flag is raised, compass and
inclinometer output data should be disregarded.

Magnetometer out of range – the magnetometer sensors are detecting an ambient magnetic
field that exceeds the maximum field measurement range of the magnetometer in any of the
three axes.

Compass Operating Modes

Standby Mode

The TCM2.5/2.6 is in Standby mode when you issue an h (Halt) command or ax (Warm Reboot).
You may configure and verify the TCM2.5/2.6’s user parameters in the Standby mode (set sampling
rate, filter parameters, and so on.) You may also query the TCM2.5/2.6 for single updates of
compass heading, pitch and roll, magnetic field strength, and temperature.

Sampling in Standby Mode

You can receive data from the TCM2.5/2.6 sensors from the h (Halt Continuous Sampling, Enter
Standby) mode. You may wish to do this if you are manually operating the TCM2.5/2.6 for
evaluation purposes, or if the TCM2.5/2.6 only needs to be polled periodically. With the TCM2.5/2.6
in the Standby mode, you can query sensor data by either issuing single parameter updates with
commands like c? (Compass Update), m? (Magnetometer Update) or you can receive output word
updates by issuing the s? (Single Update of Output Word) command. The output word may be
configured as previously described in “TCM2.5/2.6 Standard Output” to provide either NMEA
formatted compass data, or the TCM2.5/2.6 Standard output word, which presents any combination
of TCM2.5/2.6 sensor data that you wish to receive. The single parameter updates allow you to
immediately query any sensor data.

Continuous Sampling Mode

After configuring the TCM2.5/2.6 in the Standby mode, issue the go command to place the
TCM2.5/2.6 into Continuous Sampling mode. In this mode, the TCM2.5/2.6 samples its sensors,
processes, and outputs this sensor data at a rate determined by the SP parameter, default is 8 Hz.

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 16 of 49

User Calibration

All compasses can perform well in a controlled environment, where the ambient magnetic field
consists solely of the earth’s field. In most practical applications, however, an electronic compass
module will be mounted in a host system such as a vehicle that can contain large sources of local
magnetic fields: ferrous metal chassis, transformer cores, electrical currents, and permanent
magnets in electric motors.

By performing the user calibration procedure, you allow the TCM2.5/2.6 to identify the major
sources of these local magnetic anomalies and subsequently cancel out their effects when

measuring the earth’s magnetic field for computing compass headings. When you perform the user

calibration procedure, the TCM2.5/2.6 takes a series of magnetic field measurements. It analyzes
these total field measurements in order to identify the components that are created by the earth’s
field, which is the desired signal, from those components that are generated by the local
environment, which we wish to subtract out.

The end goal of the procedure for the TCM2.5/2.6 is to have an accurate measurement of the static
three-dimensional magnetic field vector generated by its host system at its mounting location. This
vector is subsequently subtracted out of run-time field measurement to yield the resultant earth’s
field vector.

One major benefit from the TCM2.5/2.6’s triaxial magnetometer/triaxial inclinometer system
configuration is its ability to compensate for distortion effects in all orientations throughout its usable
tilt range. As we have mentioned, a compass must measure the local field vector generated by the
host system at its current position within the system in order to accurately calibrate. Because the
TCM2.5/2.6’s magnetometer is strapped-down, or fixed with respect to its host system, this local
field vector does not change as the host system’s attitude changes, allowing the TCM2.5/2.6 to
accurately compensate in all pitch and roll orientations. Gimbaled fluxgates, for instance, are
unable to provide accurate calibration in non-level orientations because its magnetometers, being
gimbaled, change position with respect to the host system as attitude changes. This presents a
different local distortion field than that measured during calibration.

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 17 of 49

Multipoint Calibration (mpcal)

Key Points

Tilt as much as possible during the calibration. This allows the compass to take full

advantage of the 3-axis magnetometer.

Move slowly, take as much as 30 seconds to complete a circle. You are trying to get an

even sampling of the magnetic field over as many headings and tilts as possible.

Pay attention to the calibration score. Performance will be compromised if you accept a

low score.

If you get a poor calibration, clear it before making a new calibration.

Procedure

1. Clear any previous calibration by sending cc.

2. Enable multipoint calibration by sending mpcal=e.

3. Put the TCM2.5/2.6 into continuous mode by sending go.

4. Begin rotating the TCM2.5/2.6 in a circle while applying pitch and roll to the unit. The unit will
have the appearance of a “wobbling top” as it is moved through the calibration routine.

Turn the TCM2.5/2.6 around at least twice changing the pitch and roll as much as possible.

Each turn should take longer than 30 seconds. The turn does not need to be a perfect
circle.

In the calibration mode, the TCM2.5/2.6 is trying to take as many different data points as

possible to determine the magnetic anomalies.

The more pitch and roll points you give it, the better it is able to determine the vertical

magnetic fields.

Apply as close to a ± 90˚ pitch and ± 90˚ roll as possible. Doing so will improve the quality

of the calibration. Do not worry about exceeding the tilt range of the unit.

5. Halt the TCM2.5/2.6 by sending h if halt=e; or h <return> if halt=d.

6. Finish the calibration by sending mpcal=d.

7. Check the calibration score by sending lc?.

If the calibration score is not satisfactory, repeat the calibration process

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 18 of 49

Interpreting the Calibration Score

The TCM2.5/2.6 provides feedback on calibration through the calibration score, which has

the following format: “...HnVnMn.n....”

The first two numbers in the calibration score, HnVn, respectively describe the quality of the

calibration for the horizontal component and vertical component of the host system’s local

magnetic field. Higher numbers reflect higher quality. The highest possible score is a “9”.
The factors that contribute to a good score for Hn and Vn are as follows:

a good, magnetically quiet location was chosen for the user calibration procedure.
the magnetic environment is stable; there are no large sources of changing fields.
the calibration data points included changes in system heading and inclination to

allow for proper measurement of the horizontal and vertical field vectors.

there are no significant soft-iron distortion effects.

The last number in the score, Mn.n, describes the magnitude of local field. Larger numbers
denote strong local fields. Small local fields are preferable, since less correction will be
necessary, and they utilize less of the magnetometers’ dynamic range. A magnitude score
greater than 30 indicates strong magnetic fields at the TCM2.5/2.6 location; you should
consider alternative mounting locations. Any score less than 10 is very good.

Note: The calibration score values mostly provide a qualitative estimation. For example, a
good score would be H9V9Mn.n. A poor score as anything less than H9V9Mn.n. A poor V
score generally indicates that you need to tilt more during the calibration. A poor H score
indicates you did not turn two full circles or that you turned too quickly.

Soft Iron Effects

The TCM2.5/2.6 can calibrate for hard iron effects, or local fields that can be modeled as
static fields such as those created by permanent magnets. Hard iron distortions are
significant in most systems. There is another class of iron effects, soft iron, that are an
amplification of magnetic fields created by highly permeable materials, such as ferrous
metals. The TCM2.5/2.6 does not compensate for soft iron effects. Soft iron effects,
however, are generally far weaker than hard iron effects in most systems, and can be more
readily defeated by choosing a suitable location to mount your compass module.

In some systems, however, it may be difficult to avoid large masses of ferrous metal that
may create non-trivial soft iron effects, such as an armor plate in a tracked vehicle. In these
instances, try to locate the module as far away from the ferrous metals as possible. Soft
iron effects decrease with distance by an inverse square relation so even modest
separation can be effective.

Other Limitations

As discussed, the TCM2.5/2.6 models local disturbances as a static magnetic vector

contribution to the earth’s field. Any local fields, which are not static, will create errors. You

cannot calibrate for anomalies that are not fixed with respect to the compass. For example,
you may know that the TCM2.5/2.6 will be used in close proximity to other vehicles. You
cannot calibrate for the effects of these other vehicles, as they will be moving with respect
to the TCM2.5/2.6. This is a limitation universal to all compasses. Consider, therefore, the
TCM2.5/2.6’s position relative to any potential sources of field that will not be static:
magnetic cargo or payloads that may be placed in close proximity, fans or other electrical
equipment that may be turned on and off, and so on.

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 19 of 49

The TCM2.5/2.6 can calibrate for any environment that creates a magnetic field that
does not exceed the dynamic range of its magnetometers.

Declination Value

Declination, also called magnetic variation, is the difference between true and magnetic north,
relative to a point on the earth. It is measured in degrees east or west of true north. Correcting for
declination is accomplished by storing the correct declination angle, and then changing the heading
reference from magnetic north to true north. Declination angles vary throughout the world, and
change very slowly over time. For the greatest possible accuracy, go to the National Geophysical
Data Center web page below to get the declination angle based on your latitude and longitude:

http://www.ngdc.noaa.gov/cgi-bin/seg/gmag/fldsnth1.pl

Pitch and Roll

The TCM2.5/2.6 uses accelerometers to measure the orientation of the compass with respect to
gravity. Since the compass also measures the complete magnetic field, the TCM2.5/2.6 can
correct for the tilt of the compass to provide an accurate heading.

The TCM2.5/2.6 utilizes Euler angles as the method for determining accurate orientation. This
method is the same used in aircraft orientation where the outputs are Heading (Yaw), Pitch and Roll.
When using Euler angles pitch and roll are defined as the angle rotated around an axis through the
center of the fuselage; pitch is rotation around an axis through the center of the wings. These two
rotations are independent of each other since the rotation axes rotate with the plane body.

For the TCM2.5/2.6 a positive pitch is when the front edge of the board is rotated upward and a
positive roll is when the right edge of the board is rotated downward.

Figure 3: TCM2.5 Pitch & Roll Axes

Figure 4: TCM2.6 Pitch & Roll Axes

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 20 of 49

Command

Description

Request for Data Commands

c?

Compass Update

i?

Inclinometer Update

lc?

Query Last Calibration Score

m?

Magnetometer Update

s?

Single Update Output Word

t?

Temperature Update

Action Commands

cc

Clear Calibration Data

factory

Factory Settings

go

Enter Continuous Mode

h

Halt Continuous Sampling, Enter Standby

halt=

Enable Single Character Halt

mpcal=

Multipoint Calibration

sleep

Sleep Mode (improved sleep mode over TCM2)

wake

Wake Mode (requires separate program and connection of RTS pin)

ax

Warm Reboot

User Configuration Parameter Commands

b=

Set Baud Rate

damping=

Enable Filter for damping of output

ec=

Enable Compass Data for Output Word

em=

Enable Magnetometer Data for Output Word

ep=

Enable Pitch Data for Output Word

er=

Enable Roll Data for Output Word

et=

Enable Temperature Data for Output Word

ma=

Select Magnetometer Output Option

mag_dec=

Set Declination Angle

sdo=

Set RS232 Output Word Format

sn=

Select Magnetic or True North

timeconst=

Set the value for filtering (damping) of outputs.

uc=

Set Compass Units

ui=

Set Inclinometer Units

ut=

Set Temperature Units

Programming Commands

Table 5: Command List Quick Reference

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 21 of 49

Command differences between the TCM2.5/2.6 and previous TCM2 units

Command

Description

Commands not used for the TCM2.5/2.6

autocal

Autocalibration

%skip=

Skip measurements

cclip=

Set Clip Value

clock=

Set Clock rate

ed=

Enable Magnetic Distortion Alarm

fast=

Enable Fast Sampling

sao=

Select Analog Output Option

save

Unit automatically saves any changed settings

seriallp=

Lower Power Serial Consumption (specific to older chip)

To keep the software compatible with existing systems, when any of the commands below are sent

the unit will respond with the “:” as if it had accepted the command. Querying the command will

result in an error code, since the command is obsolete and not being used.

Table 6: TCM2 vs TCM2.5/2.6 Commands

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 22 of 49

Request for Data Commands

Query Commands

c? (Compass Update)

Description Samples the magnetometer and inclinometer sensors, then calculates and returns

the compass heading. When in Standby mode (h) use this command to query the
compass reading regardless of whether compass data has been selected for

inclusion in the output word.

Syntax c?<cr>

Output when compass units are set to degrees:

$Cnnn.n[Ennn]*checksum<cr><lf>:<cr><lf>

when compass units are set to mils:

$Cnnn.n[Ennn]<cr><lf>:<cr><lf>

Resolution 0.1˚ or 2 mils

Valid Values 0 to 359.9˚ or, 0 to 6399 mils

Example If TCM2 is configured for degrees:

c?<cr>

$C255.5[Ennn]*checksum<cr><lf>:<cr><lf>

If TCM2 is configured for mils:

c?<cr>

$C4480[Ennn]*checksum<cr><lf>:<cr><lf>

Related Commands uc= (Set Compass Units)
ec= (Compass Data Enable)

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 23 of 49

i? (Inclinometer Update)

Description Samples and returns the pitch and roll inclinometer data. When in Standby mode (h)

use this command to query the inclinometer readings regardless of whether

inclinometer data has been selected for inclusion in the output word.

Syntax i?<cr>

Output When the inclinometer units are set to degrees:

$P(-)nn.nR(-)nn.n[Ennn]*checksum<cr><lf>:<cr><lf>

When inclinometer units set to mils:

$P(-)nnnR(-)nnn[Ennn]*checksum<cr><lf>:<cr><lf>

Resolution 0.1° or 2 mils

Valid Values 0 to +80 ° or, 0 to +1421.6 mils

Example i?<cr>

$P-30.0R-20.1[Ennn]*checksum<cr><lf>:<cr><lf>

Related Commands ep= (Enable Pitch)
er= (Enable Roll)

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 24 of 49

lc? (Query Last Calibration Score)

Description Reports the score generated by the last calibration procedure executed, as stored in

EEPROM. Use this command to recall the quality of the last calibration procedure.

Syntax lc?<cr>

Output HnVnMn.nn<cr><lf>

Valid Values 0-9 for H and V

Example lc?<cr>

H7V8M8.00<cr><lf> !An example of a poor score

Related Commands mpcal (Multipoint Calibration)

m? (Magnetometer Update)

Description Samples and returns the X, Y, and Z axes of magnetometer data. When in Standby

mode (h) use this command to query the magnetometer readings regardless of

whether magnetometer data has been selected for inclusion in the output word.

Syntax m?<cr>

Output $X(-)nn.nnY(-)nn.nnZ(-)nn.nn[Ennn]<cr><lf>:<cr><lf>

Resolution 0.01 µT

Valid Values 0 to ±79.9 µT

Example m?<cr>

$X25.00Y10.50Z-03.00[Ennn]*checksum<cr><lf>:<cr><lf>

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 25 of 49

Related Commands em= (Enable Magnetometer)

s? (Single Update of Output Word)

Description Transmits the output word you specified. This command can only be used in the

Standby (h) mode. The Select RS232 Output Word Format (sdo=) command allows
you to select between NMEA or TCM2.5/2.6 Standard formats for the output word. If
TCM2.5/2.6 Standard output is selected, only those data parameters that are
enabled (with ec, ep, er, em, et) will be output.

Syntax s?<cr>

Output Refer to “RS232 Data Output Word” for a full description of the output word formats.
Example s?<cr>

$C328.3P28.4R-12.4X55.1Y12.3Z-18.4T22.3[Ennn]*check-

sum<cr><lf>:<cr><lf>

Related Commands sdo= (Select RS232 Output Word Format)
ec= (Enable Compass Data for Output Word)
ep= (Enable Pitch Data for Output Word)
er= (Enable Roll Data for Output Word)
em= (Enable Magnetometer for Output Word)
et= (Enable Temperature Data for Output Word)

t? (Temperature Update)

Description Sample and return the ambient temperature. When in the Standby mode (h) use

this command to query the temperature readings regardless of whether temperature

data has been selected for inclusion in the output word.

Syntax t?<cr>
Output When the units are set to Celsius:

$T(-)nnn.n[Ennn]*checksum<cr><lf>:<cr><lf>

When units set to Fahrenheit:

$T(-)nnn[Ennn]*checksum<cr><lf>:<cr><lf>

Resolution 0.5 °C or 1 °F

Valid Values -40.0 to 85.0 °C or -40 to 185 °F

Example t?<cr>

$T25.5[Ennn]*checksum<cr><lf>:<cr><lf>

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 26 of 49

Related Commands et= (Enable Temperature)

ut= (Set Temperature Units)

Action Commands

? (Help Command)

Description All TCM2.5/2.6 commands are displayed using the “?” command.

cc (Clear Calibration Data)

Description Erases all calibration data. Any further magnetometer or compass output is not

corrected for any local fields. This command is only valid during Standby Mode (h).
Use this command before recalibrating the TCM2.5/2.6 for a new or changed local

magnetic environment.

Syntax cc<cr>
Output HnVnMn.nn<cr><lf>
Example cc<cr>

H0V0M0.00<cr><lf>

Query Response lc? (Last Calibration Score)

Related Commands mpcal= (Multipoint Calibration)
c? (Compass Update)

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 27 of 49

factory (Factory Settings)

Description Resets the TCM2.5/2.6 to the factory settings. The internal modes are set to the

following factory defaults

b=5 er=e mpcal=d ut=c
cc et=d sdo=t
damping=d timeconst=8 sn=m
ec=e halt=d sp=8
em=d ma=u uc=d
ep=e mag_dec=0.0 ui=d

Syntax factory<cr>

Output H0V0m0.00<cr><lf>

Example factory<cr>

go (Enter Continuous Sampling Mode)

Description Enters the Continuous Sampling Mode (go). The TCM2.5/2.6 immediately begins

outputting sensors data at rate specified by the SP parameter, default is 8 Hz. Data is
automatically transmitted according to the Output Word Format (sdo=) currently
specified. To exit the TCM2.5/2.6 and return to Standby mode, issue the Halt

Continuous Sampling (h) command.

Syntax go<cr>
Output Selected data output word.
Example go<cr>
Related Commands s? (Single Update of Output Word)

h (Halt Continuous Sampling)

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 28 of 49

h (Halt Continuous Sampling, Enter Standby)

Input

Description

e

Enable, h command for halting the ouput

d

h <cr> command for halting the output (default setting)

Description Exits Continuous Sampling Mode (go) and enters Standby mode (h). If this

command is received while the TCM2.5/2.6 is transmitting an output word, the

remainder of the output word will be sent before the TCM2.5/2.6 changes modes.

Syntax h<cr>
Output :[Ennn]<cr><lf>
Related Commands go (Enter Continuous Sampling Mode)

halt= (Enable Single Character Halt)

halt= (Enable Single Character Halt)

Description The halt command during go mode has optionally been made a single character
command using the halt=e command.

Syntax halt=d<cr>
Output :[Ennn]<cr><lf>
Valid Values

Table 7: Valid halt= Values

Query Response halt? :halt=

Related Commands go (Enter Continuous Sampling Mode)

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 29 of 49

mpcal= (Multipoint Calibration)

Input

Description

e

e, enable multipoint calibration

d

d, disable multipoint calibration (default setting)

Description Initiates a multipoint calibration. This command is only valid when used in

conjunction with Enter Continuous Sampling Mode (go). The TCM2.5/2.6 samples its

sensors and adds the data point to the current set of calibration data.

Syntax mpcal=e<cr>

:<cr><lf>

go<cr>

.......

...... take data in continuous mode

h<cr> (or h)

:<cr><lf>

mpcal=d<cr>

Valid Values

Table 8: Valid mpcal= Values

Output HnVnMn.nn<cr><lf>

The TCM2.5/2.6 only reports a calibration score after it has been put in Standby mode (h), and
multipoint calibration has been disabled (mpcal=d)

Example mpcal=e<cr>

:<cr><lf>

go<cr>

........

....... take data in continuos mode

h<cr>

:<cr><lf>

mpcal=d<cr>
H4V3M5.00:<cr><lf> (This is an example of a poor score)

Query Response mpcal? :mpcal=

Related Commands lc? (Query Last Calibration Score)

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 30 of 49

sleep (Sleep Mode)

Description Enters the sleep mode of operation. This command turns off the internal clocks and

the RS-232 chip.

Syntax sleep<cr>
Output

Example

Related Commands wake (Wake Mode)

wake (Wake Mode)

Note: Only used with the TCM2.5

Description Enters the wake mode of operation. To wake the TCM2.5, a falling edge on the int2

(interrupt 2) pin of the processor is required. This is achieved by connecting pin 6
of the TCM2.5 connector to the RTS pin (pin 4 on a DB25 and pin 7 on a DB9) of

the COM port.

A sample wake.c program example is provided at the end of this document. To
wake the TCM2.6, toggle RxD line

Syntax wake<cr>

Output

Example

Related Commands sleep (Sleep Mode)

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 31 of 49

User Configuration Parameter Commands

Input

Baud Rate

1

300

2

1200

3

2400

4

4800

5

9600 (default setting)

6

19200

7

38400

8

115200

The following commands allow you to set and query the values of the TCM2.5/2.6’s user configura­tion parameters. These parameters specify how the TCM2.5/2.6 will operate, such as damping,
baud rate, and so on. The TCM2.5/2.6 stores all parameter values in EEPROM when specified, so
that after a reboot or power cycling, it will return to the last configuration set. Note that any parame­ter that specifies a numeric value must be specified with the appropriate units of the current setting.

b= (Set Baud Rate)

Description Sets the baud rate for the RS232 interface. Note: This is now an immediate

command and a reset is no longer required.

Syntax b=n<cr>

Output :<cr><lf>

Valid Values

Example b=5<cr> !set baud rate to 9600 baud

:<cr><lf>

Query Response b? :b=

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 32 of 49

Table 9: Valid b= Values

damping= (Set Digital Damping)

Input

Description

e

enable damping

d

disable damping (default setting)

Description Enables or disables filtering of the output.
Syntax damping=n<cr>
Output :[Ennn]<cr><lf>
Valid Values

Table 10: Valid damping= values

Example damping=e<cr> !enable damping

:<cr><lf>

Query Response damping? :damping=

Related Commands timeconst= (set time constant for digital damping)

ec= (Enable Compass Data for Output Word)

Description Enables or disables compass data for inclusion in the TCM2.5/2.6 Standard Output
Word.

Syntax ec=n<cr>

Output :[Ennn]<cr><lf>

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 33 of 49

Valid Values

Input

Description

e

Compass data enabled. It will be included in the output word. (Default setting)

d

Compass data disabled. It will be excluded in the output word

Input

Description

e

Magnetometer data enabled. It will be included from the output word.

d

Magnetometer data disabled. It will be excluded in the output word. (Default setting)

Table 11: Valid ec= Values

Example ec=e<cr> !include compass data in output word

:<cr><lf>

Query Response ec? :ec=

em= (Enable Magnetometer Data for Output Word)

Description Enables or disables magnetometer data for inclusion in the TCM2.5/2.6 Standard

Output Word

Syntax em=n<cr>

Output :[Ennn]<cr><lf>
Valid Values

Table 12: Valid em= Values

Example em=e<cr> !enable magnetometer data

:<cr><lf>

Query Response em? :em=

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 34 of 49

ep= (Enable Pitch Data for Output Word)

Input

Description

e

Pitch data enabled. It will be included from the output word. (Default setting)

d

Pitch data disabled. It will be excluded in the output word

Description Enables or disables pitch data for inclusion in the TCM2.5/2.6 Standard Output Word.

Syntax ep=n<cr>

Output :[Ennn]<cr><lf>
Valid Values

Table 13: Valid ep= Values

Example ep=e<cr> !include pitch data in output word

:<cr><lf>

Query Response ep? :ep=

er= (Enable Roll Data for Output Word)

Description Enables or disables roll data for inclusion in the TCM2.5/2.6 Standard Output Word.

Syntax er=n<cr>

Output :[Ennn]<cr><lf>

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 35 of 49

Valid Values

Input

Description

e

Roll data enabled. It will be included from the output word. (Default setting)

d

Roll data disabled. It will be excluded in the output word

Input

Description

e

Temperature data enabled. It will be included from the output word.

d

Temperature data disabled. It will be excluded in the output word. (Default setting)

Table 14: Valid er= Values

Example er=e<cr> !include roll data in output word

:<cr><lf>

Query Response er? :er=

et= (Enable Temperature Data for Output Word)

Description Enables or disables temperature data for inclusion in the TCM2.5/2.6 Standard

Output Word.

Syntax et=n<cr>

Output :[Ennn]<cr><lf>
Valid Values

Table 15: Valid et= Values

Example et=e<cr> !include temperature data in output word

:<cr><lf>

Query Response et? :et=

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 36 of 49

ma= (Select Magnetometer Output Option)

Input

Description

c

Choose corrected magnetometer readings.

u

Choose non corrected magnetometer readings.
(Default setting)

Description Outputs either corrected or non corrected magnetometer readings. If corrected

readings are selected, the magnetometer readings output by the TCM2.5/2.6 reflect
corrections to ambient field as a result of user calibration. If not corrected, the
magnetometer readings output reflect total ambient field, including local fields. Note
that compass readings always are based upon corrected magnetometer readings.

Syntax ma=n<cr>

Output :[Ennn]<cr><lf>

Valid Values

Table 16: Valid ma= Values

Example ma=c<cr> !corrected magnetometer readings

:<cr><lf>

Query Response ma? :ma=

mag_dec= (Set Declination Angle)

Description Sets the magnetic declination angle in degrees. Sets the declination offset for a

reading of True North. Based on the setting of the Compass Units (uc) command.
Positive declination is easterly declination and negative is westerly declination. This

is not applied until True North is set to true.

Syntax mag_dec=nn.n<cr>

Output :[Ennn]<cr><lf>

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 37 of 49

Valid Values

Input

Description

nn.n

Declination angle in degrees (default is set to 0.0)

Input

Description

t

Standard TCM output string (default)

n

NMEA 0183 output string

Table 17: Valid mag_dec= Values

Example mag_dec=17.2 !sets the declination angle to 17.2 degrees

:<cr><lf>

Query Response mag_dec? :mag_dec=

sdo= (Set RS232 Output Word Format)

Description Sets the output word format to be used in response to the Single Update Output

Word (sdo?) command and in Continuous Output Mode (go).

Syntax sdo=n<cr>

Output :[Ennn]<cr><lf>

Valid Values

Table 18: Valid sdo= Values

Example sdo=t<cr> !output word format to TCM standard

:<cr><lf>

Query Response sdo? :sdo=

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 38 of 49

sn= (Select Magnetic or True North)

Input

Description

t

True North

m

Magnetic North (default setting)

Description Selects either magnetic or true north. True North sets the heading reference to True

North or Magnetic North. If the value is set to true, then declination is applied to get
the True North heading.

Syntax sn=n<cr>

Output :[Ennn]<cr><lf>

Valid Values

Table 19: Valid sn= Values

Example sn=t<cr> !the declination angle set with mag_dec is added to the

!computed heading

:<cr><lf>

Query Response sn? :sn=
Related Commands mag_dec= (Set Declination Angle)

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 39 of 49

sp= (Set Sampling Period)

Input

Description

1

1 Hz output rate

2

2 Hz output rate

3

3 Hz output rate

4

4 Hz output rate

5

5 Hz output rate

6

6 Hz output rate

7

7 Hz output rate

8

8 Hz output rate (default)

Description This command is used to set the sampling rate at which the data will be output in Hz.

NOTE: The function of this command has changed from the TCM2 in which the sp
was the clock divisor to derive the output rate.

Syntax sp=n<cr>
Output : [Ennn] <cr><1f>

Valid Values

Table 20: Valid sp= Values

Example sp=4<cr> !output rate 4 Hz

:<cr><lf>

Query Response sp? :sp=

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 40 of 49

timeconst= (Set Time Constant for Digital Damping)

Input

Description

Integer value between 1 – 4

Set the measured time constant = 4

Integer value between 5 – 8

Set the measured time constant = 8 (default setting)

Integer value between 9 – 16

Set the measured time constant = 16

Integer value between 16 – 32

Set the measured time constant = 32

Description This command is used with the digital damping command. It sets the time constant to

nn samples for the digital damping.

Syntax timeconst=n<cr>

Output :[Ennn]<cr><lf>

Valid Values

Table 21: Valid timeconst= Values

Example timeconst=16<cr> !Filter over 16 measurements

:<cr><lf>

Query Response timeconst? :timeconst=
Related Commands damping= (Set Digital Damping)

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 41 of 49

uc= (Set Compass Units)

Input

Description

d

degrees, 360 × in a full circle (Default setting)

m

mils, 6400 mils in a full circle

Input

Description

d

degrees, 360 × in a full circle (Default setting)

m

mils, 6400 mils in a full circle

Description Sets the units to be used for the input and output of the heading data.

Syntax uc=n<cr>

Output :[Ennn]<cr><lf>

Valid Values

Table 22: Valid uc= Values

Example uc=d<cr> !set units to degrees

:<cr><lf>

Query Response uc? :uc=

ui= (Set Inclinometer Units)

Description Sets the units to be used for the input and output of the tilt (pitch & roll) data.

Syntax ui=n<cr>

Output :[Ennn]<cr><lf>

Valid Values

Table 23: Valid ui= Values

Example ui=d<cr> !set units to degrees

:<cr><lf>

Query Response ui? :ui=

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 42 of 49

ut= (Set Temperature Units)

Input

Description

f

Fahrenheit

c

Celsius (Default setting)

Description Sets the units to be used for the input and output of the temperature data.

Syntax ut=n<cr>

Output :[Ennn]<cr><lf>

Valid Values

Table 24: Valid ut= Values

Example ut=f<cr> !set units to Fahrenheit

:<cr><lf>

Query Response ut? :ut=

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 43 of 49

TCM2.5/2.6 Code Example

Wake C program

/* wake.c - Sample program to wake the TCM2.5/2.6 after is has been put
in sleep mode */
/* Wake toggles the RTS line to give the TCM2.5/2.6 a (falling) edge */
/* P Milford 1/10/96 */

/* Usage: wake 1 - wakes a tcm2.5/2.6 on com port 1 (default) */
/* wake 2 - wakes a tcm2.5/2.6 on com port 2, etc. */

#include <stdio.h>
#include <stdlib.h> /* for atoi */
#include <conio.h> /* For inp/out */

/* Addresses in IO space of the serial port base addresses */

#define PORT1 0x3F8
#define PORT2 0x2F8
#define PORT3 0x3E8
#define PORT4 0x2E8

#define MCR 4 /* Offset to the Modem control register */
#define RTS 2 /* RTS is bit 2 of the MCR*/

int main(int argc, char *argv[])

{

int tmp, port=PORT1; /* Defaul to serial port 1 */

/* If there are args, look at the first one only */

if(argc == 2) { /* Figure out which serial port to use */
switch(atoi(argv[1])) {
case 1: port = PORT1; break;
case 2: port = PORT2; break;
case 3: port = PORT3; break;
case 4: port = PORT4; break;
others: port = PORT1;
};
};
tmp = inp(port+MCR); /* Read current line status */
outp(port+MCR, tmp ^ RTS); /* Toggle the RTS line */
outp(port+MCR, tmp); /* Restore the RTS line */

return 0;

};

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 44 of 49

Performance Specifications

Parameter

Typical

Units

Heading Specifications

Accuracy over tilt range

0.8°

Deg RMS

Resolution

0.1°

Repeatability [1]

0.1°

Max Dip Angle

85°

Deg

Magnetometer Specifications

Calibrated Field Measurement
Range

± 80

µT

Magnetic Resolution

± 0.05

Magnetic Repeatability

± .1

Tilt Specifications

Pitch Accuracy

0.2°

Deg RMS

Roll Accuracy

0.2°

Tilt Range

± 50°

Deg

Tilt Resolution

0.1°

Tilt Repeatability [1]

0.1°

Deg RMS

Calibration

Hard Iron Calibration

Yes

Soft Iron Calibration

No

Mechanical Specifications

TCM2.5

TCM2.6

Dimensions (L x W x H)

6.4 x 5.1 x 1.4

3.4 x 4.3 x 1.3

cm

Weight

14

7

grams

Mounting Options

Screw Mounts/Standoffs horizontal

Connector for RS-232

10-pin

9-pin

I/O Specifications

Time to Good Initial Data from
Power-On

210

msec

Time to Good Initial Data from
Sleep Mode

80

msec

Maximum Sample Rate

8

samples/sec

RS-232 Communication Rate

300 to 115200

baud

Output Formats

TCM2 ASCII Protocol

Power Specifications

TCM2.5

TCM2.6

Supply Voltage

5 V (regulated)

6 to 18 (unregulated)

3.8 to 5.0 V

(unregulated)

VDC

Current Draw at
maximum sample rate

20 typical

20 typical

mA

Sleep Mode

0.6 typical

0.6 typical

Environmental Specifications

Operating Temperature

– 20 to 70

°C

Storage Temperature

– 40 to 85

[1] Repeatability is based on statistical data at ±3 sigma limt about the mean

Table 25: TCM2.5/2.6 Specifications

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 45 of 49

Mechanicals

TCM2.5 Board and Cable

The default orientation for the TCM2.5/2.6 is for the silk-screened arrow to point in the “forward”
direction. That puts the edge opposite of the Molex connector as the front edge of the board.

Figure 5: TCM2.5 Board Drawing

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 46 of 49

3 ft. Cable Assembly

PIN

Wire Color

Description

1

Orange

Vsupply (5 V regulated)

2

Red

Vsupply (6 to 18 V unregulated)

3

Black

Power Ground

4

Blue

RxD (RS-232) -5 to 5V

5

Yellow

TxD (RS-232) -5 to 5V or -12 to 12V

6

White

RTS, Wake from Sleep

7

Green

Data Ground

8

Brown

NC 9 Purple

NC

10

Gray

Data Ground

Figure 6: 3’ Cable Drawing

Table 26: Molex Connector TCM2.5 Pin Descriptions

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 47 of 49

TCM2.6 Board and Cable

The default orientation for the TCM2.6 is for the silk-screened arrow to point in the “forward”
direction. That puts the edge opposite of the Molex connector as the front edge of the board.

Figure 7: TCM2.6 Board Drawing

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 48 of 49

18 in. Cable Assembly

PIN

Wire Color

Description

1

Black

Power Ground

2

Gray

NC 3 Green

RS232 Ground

4

Orange

NC 5 Violet

NC 6 Brown

NC 7 Yellow

TxD

8

Blue

RxD

9

Red

5 VDC

Figure 8: 18" Cable Drawing

Table 27: Molex Connector TCM2.6 Pin Description

PNI Sensor Corporation DOC#1009269 r11
TCM2.5 & TCM2.6 User Manual Page 49 of 49