Salutron HRM8700 Heart rate module User Manual

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HRM8700

Combo Heart Rate Module

User Guide

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FCC ID:N7P-HRM8700

IC:10274A-HRM8700

FCC ID:N7P-HRM8700FCC ID:N7P-HRM8700FCC ID:N7P-HRM8700FCC ID:N7P-HRM8700

IC:10274A-HRM8700IC:10274A-HRM8700IC:10274A-HRM8700IC:10274A-HRM8700

CONFIDENTIAL

Revision History:

Revision Release

date Description B

y

0.1 07/23/17 Preliminary Draft BC

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Contents

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General Description .............................................................................................................................. 4

Features: ............................................................................................................................................. 4

Physical Dimensions: Inches (mm) ......................................................................................................... 5

Connection Diagram: (Typical) .............................................................................................................. 6

Electrical Characteristics: ...................................................................................................................... 7

ECG Measurement: ............................................................................................................................... 7

5KHZ Wireless Specification: ................................................................................................................. 7

BLE/ANT+ Specification: ....................................................................................................................... 7

1. UART COMMUNICATION PROTOCOL: ................................................................................................. 9

1.2.Block Diagram .......................................................................................................................................... 9

2. OPERATION ..................................................................................................................................... 9

2.1. Description............................................................................................................................................... 9

2.2. UART Specification .................................................................................................................................. 9

2.3. Equipment Assomptions ........................................................................................................................ 10

2.4. HRM8700 default configuration ............................................................................................................. 10

2.5. Equipment and HRM8700 Operations ................................................................................................... 11

2.6. HRM8700 OTA. ...................................................................................................................................... 12

3. UART COMMUNICATION PROTOCOL PACKETS ................................................................................... 13

3.1. Packets .................................................................................................................................................. 13

3.2. Example of Sending Packets Equipment Console .................................................................................. 13

3.3. Example of Sending Packet to HRM8700 .............................................................................................. 14

Appendix A : Grounding and ESD Recommendations .............................................................................. 15

Appendix B: HRM8700 Placement Guideline ........................................................................................... 18

FCC/IC statement ................................................................................................................................ 20

FCC statement .............................................................................................................................................. 20

IC statement ................................................................................................................................................. 20

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CONFIDENTIAL

Model HRM8700

Wireless Heart Rate Monitor Specifications

General Description

 The Model HRM8700 is a wireless receiver and

Handgrip Heart Rate Monitor Combo. It is

designed to manage and support ECG contact

heart rate and the reception of wireless heart

rate data from BLE, ANT+, standard 5kHz

chest straps or wearable heart rate

transmitters or devices.

 Once enabled by the Console, the HRM8700

actively scans for local HR transmitter signals,

and supports a user selection/pairing protocol

processed by the Console.

 Once a HR transmitter is selected/paired, the

HRM8700 streams the user heart rate data

until the end of the workout session, then

‘unpairs’.

 The HRM8700 contact heart rate monitor can

quickly and accurately measure the heart rate

from an ECG signal under noisy environments.

 The HRM8700 simultaneously processes

Handgrip Heart Rate and Wireless Heart Rate

data. Either can be specified as the priority

heart rate.

Features:

 Direct connection to equipment; no phone

device or app ‘middleman’

 Support ECG contact heart rate

 Supports multiple inbound sources for HR:

BLE, ANT+, 5kHz

 Automatic proximity sensing to minimizing

interference from competing wireless HR

signals

 Console controllable proximity commands

allowing ‘customization’ of the scanning

proximity during integration development of

the HRM8700 into the console

 Simplified user pairing routine

 Future-proof: OTA updateable to support

future features (based on console pass-

through, if available)

 Interface: UART, custom command protocol

The HRM8700 series combo heart rate module

delivers high performance ECG contact and

telemetry heart rate monitoring - for both

commercial/club and home cardio equipment

applications.

The HRM8700 communicates and passes the

heart rate data from the heart rate monitor to the

equipment console through proprietary UART

protocol.

The HRM8700 series offers a special proximity

pairing feature that allows the equipment console

to discover only the HR transmitting devices in

close proximity. This feature minimizes unwanted

devices and speeds up the pairing process,

especially useful in health club environments

where there may be multiple BLE or ANT+

devices present. After successful pairing, the

reception distance will automatically increase to

maximum range.

The HRM8700 receiver also supports legacy S-

pulse contact heart rate and 5kHz chest strap

data reception. It utilizes Salutron’s proprietary

Digital Crosstalk Control and Digital Noise Filter

algorithms that can filter out unwanted competing

chest strap signals. This supports better wireless

reception and reduce 5kHz noise from potentially

unfriendly high ‘noise’ environments coming from

power systems and console electronics.

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o ECG handgrip contact heart rate with R-R

interval output (Optional)

o BLE smart and ANT+ data reception

o Standard 5.3kHz chest strap, coded and un-

coded signal reception

o Proximity pairing feature.

o UART communication protocol

o Stationary Bike FE-C support

o 3~6V operation.

o RoHS compliant.

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Physical Dimensions: Inches (mm)

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Figure1:Physicaldimensions

The physical properties of the HRM8700 allow for easy integration in your existing equipment. See above

picture for the physical dimensions of the board. Preferred headers may be specified, with Salutron’s

consultation. Because of its small size and weight, the board can be fastened using adhesive tape, or #2

screws.

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Connection Diagram: (Typical)

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Figure 2: Connection Diagram

TYPE PIN No. DESCRIPTION

HD1 – Ground Strap 1 Earth Ground

HD2 – Right Sensor

1 RA, right primary sensor

2 LL, common sensor

3 Shield

HD3 – Left Sensor

1 LA, left primary sensor

2 LL, common sensor

3 Shield

J1 – Main

1 GND

2 +5V

3 TXD

4 RXD

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Electrical Characteristics:

Symbol Parameter Conditions Min. Typ. Max. Units

VS Supply voltage - 3 5 6 V

IS Supply current Vcc = 5V 5.2 7.5 10.5 mA

To Operating Temperature - -10 - 60 °C

Ts Storage Temperature - -40 - 85 °C

ECG Measurement:

Symbol Parameter Conditions Min. Typ. Max. Units

HR Heart EC Simulator 30 - 240 BPM

CHR sensor ECG sensitivity 0.1 - - mV

Ta Acquisition Time Bike/treadmill 3 5 10* seconds

*Among the contributing factors resulting in long HR acquisition are motion induced physiological artifact, electrical disturbance from

control electronics, transient motor drive loading, and skin contamination via hand cream, cosmetics, and dust,

5KHZ Wireless Specification:

Parameter Conditions Min. Typ. Max. Units

5KHZ Wireless reception range Noise free environment 31

80 35

90 39

100 Inches

cm

5KHZ Wireless reception

frequency T= 25ºC, Vcc =5.0V 4.8 5.3 5.9 KHz

Heart rate detection T= 25ºC, Vcc =5.0V 30 - 240 BPM

Output format UART Protocol

BLE/ANT+ Specification:

Minimum Typical Maximum Unit

HR Measurement

Range 30 - 240 beats per minute

Frequency 2402 - 2480 MHz

Center Frequency - 2440 - MHZ

Channel Bandwidth - - 2 MHZ

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Low speed Crystal Freq - 32.768 - KHZ

High speed Crystal Freq - 32 - MHZ

Channel Spacing - 2 - MHZ

No. of channels used - - 40 Channels

Modulation GFSK

Output power -20 - 4 dBm

Open Air range - - 10 Meter

Power Consumption Vdd=5.0V @ 25°C

Standby mode - 5 - mA

Operation Modes

Device Searching Mode - 10 10.5 mA

Heart rate Data transfer - 5 5.5 mA

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2.4GHZ Transmission

distance (line of sight)*

65

20

-

Feet

Meter

*Note:thenatureofphysicalobstructionsand/or2.4GHzradiointerferenceinthesurroundingarea

couldaffectthereceptionandtransmissionrange.

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CONFIDENTIAL

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1. UART COMMUNICATION PROTOCOL:

The following section describes the communication protocol between the HRM8700 and Equipment console.

The protocol is intended to provide a reliably link between the HRM8700 and Equipment console. The UART

protocol supports the two way link communication between the two devices.

1.2.Block Diagram

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2. OPERATION

2.1. Description

The Equipment console and HRM8700 uses standard UART protocol to transmit and receive custom

packets. The Equipment console controls the HRM8700 operation. The HRM8700 operations are:

 Start and stop 5Khz, BLE and ANT+ scanning

 Connect and disconnect to a heart rate transmitter using 5khz, BLE and ANT+.

 On-demand scanning

 Stationary bike FE-C broadcast is activated with user selected ID at the start of workout

 HRM display profile is broadcasted with user selected ID at the start of workout

 HRM display profile and Stationary bike have the same ID

 At the start of a workout session, the Contact Heart rate is enabled and it will stream heart rate

data if active. Contact heart rate will override the wireless data if “contact override” option is

enabled

2.2. UART Specification

Baudrate: 9600 (default), 4800, 2400, 115200

CONFIDENTIAL

Parity: No parity

Flow Control: Disable

2.3. Equipment Assomptions

Upon power up of the equipment device, the HRM8700 should also be powered up. Since the equipment is

controlling the HRM8700, the HRM8700 will be in the idle state or waiting state awaiting command from

the equipment console.

2.4. HRM8700 default configuration

Upon power up, the default settings of the HRM8700 are as follows. The equipment console if needed

could send a command to change any of the default settings at the start of the workout.

• Contact HRM Setting

Contact HRM Setting

Description Setting

Enable Contact Override OFF

Enable RR – Interval OFF

• FE-C

FE-C Setting

Description Setting

Enabled OFF

Hardware Rev 1

Manufacturing ID 1

Model Number 1

Software Revision 1

Supplementary Soft. Revision 0

Serial Number 0

Device ID 3301

• BLE

BLE Setting

Description Setting

Proximity Option 1

Enable OTA OFF

• 5khz HRM

5Khz Setting

Description Setting

Auto Connect OFF

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2.5. Equipment and HRM8700 Operations

The equipment console will send “workout” command to HRM8700 to wake it up from the idle state to scanning

state. The HRM8700 will start scanning for 5kHz, BLE and ANT+ HR transmitter advertising within its proximity.

The proximity setting is added in the “workout” command send by the console. While in the scanning state, the

Contact heart rate is always active to stream contact HR data to the console.

The HR transmitter ID that are found during scanning state will be sent to the Equipment console. For BLE, the

advertising name and BLE address are sent to the console. A separator key is added in between the advertising

name and the BLE address. See the UART package table for the details of communication protocol. All BLE HR

transmitter IDs send to the console are uniquely identified. This means there are no duplicate for BLE HR

transmitter IDs received by the equipment console.

For ANT+ the advertising ID is sent to the equipment console. There is a possibility of duplication of ANT+ HR

transmitter IDs because of the limitation of ANT+ protocol in providing certain ID information.

For 5kHz, a "5kHz HRM" name is sent. Only one 5kHz HR transmitter is send to equipment console while a

maximum five each of BLE and ANT+ HR transmitter are sent to the equipment console for a maximum of eleven

HR transmitters. Although the console can receive more than eleven devices, the limitation is due to the capacity

of HRM8700 microcontroller. Maximum capacity might change in the future or upon customer request.

After all HR transmitter IDs within the pairing proximity range are sent to the equipment console, the user is

expected to choose what type of HR transmitter to be used during workout. If the user selects the BLE HR

transmitter, the corresponding BLE address is sent back to HRM8700. The BLE address is one of the parameters

for pairing and tracking BLE HR transmitter.

If user selects an ANT+ HR transmitter, the HRM8700 will use the ANT+ advertising name for pairing and

tracking. If there are more than one ANT+ HR transmitter with the same advertising name then there might be a

chance for the user to pair to a wrong HR transmitter. For a 5kHz HR transmitter, the transmitter with the

strongest signal is expected to be paired.

After the HRM8700 successfully pairs with the selected HR transmitter, it starts streaming the heart rate data to

the console. The frequency of heart rate streaming will be dependent upon the kind of connected HR transmitter,

but for 5kHz and Contact HR it would depend upon the heart rate BPM rate.

A special process is implemented if only 5kHz is detected during scanning. By default, the HRM8700 will not wait

for user confirmation, but will directly connect to the 5kHz HR transmitter if it is the only one detected during

scanning. HR data will automatically be sent to the console after connection. However the console has an option

to override it with the “5KHZ disable auto connect” command. In this case the console will wait for user

confirmation.

The Contact mode can be configured as contact override on or off. It also can stream the R-R interval value after

a valid HR is sent to the console. The R-R interval is available in Contact HR mode only if the option is enabled.

The equipment console would need to send a “stop workout” command to disconnect the HRM8700 to the paired

HR transmitter. The HRM8700 will forget that HR transmitter and go to idle state and wait for the next

interaction.

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2.6. HRM8700 OTA.

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For the HRM8700 a new code update can be flashed by using over the air programming. The BLE DFU

feature of the HRM8700 can be triggered using the activation

command

from the console. Once triggered

the HRM8700 function as BLE peripheral and will broadcast “HRM_8700”. Using the Nordic NRF Connect

application installed in the iphone/Android phone and an OAD zip file (released by Salutron), the HRM8700

firmware can be updated. For more information and procedure on how to OTA, please refer to the

HRM8700 OAD procedure document.

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CONFIDENTIAL

3. UART COMMUNICATION PROTOCOL PACKETS

3.1. Packets

The uart protocol packets contain data that will be used as an interface between the HRM8700 and the

equipment console. A maximum of twenty four bytes and a minimum of eight bytes are used during UART

communication.

Fletcher checksum reference: https://en.wikipedia.org/wiki/Fletcher%27s_checksum

For 5kHz analog strap, the name to be transmitted will be “5kHz HRM”.

Below is the UART packet:

A response bit when set means the receiver is obliged to response acknowledgement when package is

received from the transmitting UART port

START

COMMAND PACKET LEN CHECK

SUM RESPONSE

BIT CLASS SUB DATAx

Type Size in bytes Description

START COMMAND 1 Start byte

PACKET LEN 1 Number of bytes in a packet

CHECK SUM 2 Fletcher checksum

RESPONSE BIT 1 Response bit

CLASS 1 Packet Class type

SUB CLASS 1 Packet sub-class type

DATA XX Data

3.2. Example of Sending Packets Equipment Console

Usage:

Sending packet name to equipment console

Format:

[Start Command]

[Packet Size]

[Fletcher check sum low byte]

[Fletcher check sum high byte]

[Response bit]

[Class]

[Sub Class]

[Name 1st byte]

[Name … byte]

[Name xth byte]

Packet:

ex. 5Khz advertising name = “5kHz HRM”

[0x0A]

[0x0F]

CONFIDENTIAL

[0xYY]

[0xZZ]

[0x0C]

[0x00]

[0x01]

[0x35]

[0x6B]

[0x48]

[0x7A]

[0x20]

[0x48]

[0x52]

[0x4D]

3.3. Example of Sending Packet to HRM8700

Usage:

Sending selected packet name to HRM8700

Format:

[Start Command]

[Packet Size]

[Fletcher check sum low byte]

[Fletcher check sum high byte]

[Response bit]

[Class]

[Sub Class]

[Name 1st byte]

[Name … byte]

[Name xth byte]

Packet:

ex. 5Khz advertising name = “5kHz HRM”

[0x0B]

[0x0F]

[0xYY]

[0xZZ]

[0x00]

[0x1C]

[0x01]

[0x35]

[0x6B]

[0x48]

[0x7A]

[0x20]

[0x48]

[0x52]

[0x4D]

CONFIDENTIAL

Appendix A : Grounding and ESD Recommendations

Overview

For accuracy and performance, the HRM8700 wireless receiver and heart rate monitor (HRM) combo must

be properly grounded. Improper grounding introduces unwanted noise that can overwhelm the ECG signals

and compromise the signal-to-noise ratio. Improper grounding can also leave the system vulnerable to

problems from electrostatic discharge (ESD), which can cause the console to reset. In order to provide a

stable ground for the HRM8700 and to protect from ESD, the ground needs to be free of noise and have

very low impedance.

This application note provides grounding and ESD recommendations based on common installations of the

HRM8700. The recommended method provides a dedicated ground for this board.

The above solution requires as a prerequisite a good regulated power supply. This is because when the

ESD current causes transient on the ground wire, the power supply can regulate and absorb the energy to

a certain extent so that it is not propagated to the rest of the system to cause resets.

If flat ribbon cable is used as the inter-connect between HRM and Client console, multiple circuits are

required for +5V and Return to ensure low impedance.

It is also a good practice to use a reliable supervisory integrated circuit for power up and power down

management to avoid undesired resets to the microcomputers when ESD occurs.

For treadmills, the motor drive design is also critical to ensure an electrically quiet system to meet FCC

Class A and Class B compliance. The inductive load creates radiated noise with wide band characteristics

that will compromise heart rate performance in acquisition time. (See footnote of ECG Measurement on

page 7)

CONFIDENTIAL

Wire Return

Figure A1: Wire return grounding recommendation

A wire return is an effective solution for grounding and ESD protection. However, the impedance in the

wire can limit the effectiveness in conducting ESD current. Therefore, it is recommended that a return wire

of 16 gauge is used. The wire should be made as short as possible, not to exceed 12 inches.

In Figure A1, a return wire is attached directly to HRM at HD1 hole. Because of unwanted noise, do not tie

the return wire to the ground (indicated RTN above) from the power supply but to earth ground directly.

The return wire connected to the earth ground can be ordered pre-assembled with the HRM8700. See the

“Order Information“ section for order details.

Console Power

Supply

Plastic Back Panel

HRM

+5V RTN Interconnect

Earth Ground

Attach return wire (attached to HRM at HD1)

directly to earth ground.

Vcc

RTN

Return wire

CONFIDENTIAL

ESD Protection

The independent return wire described earlier also serves as an ESD return path when electrostatic

discharge occurs. The high voltage protection circuit in the HRM will cause the discharging current to pass

through this independent ground path. Therefore, the console is less likely to latch up due to the

incomplete reset caused by unpredictable ESD current.

The return ground does not conduct current unless ESD occurs. However, when ESD occurs, the ground

must have low impedance to discharge the ESD energy. To ensure low impedance, a 16 gauge copper

wire is recommended for ESD protection. The length of the wire should not be made longer than 12

inches. The wire should be bolted to the closest spot in the equipment where a reliable chassis ground is

available.

A dedicated ground plane in the console PCB may help to reduce the chance of latch-up when ESD fires.

A good supervisory IC is highly recommended to reduce possibilities of resetting the console, too.

The HRM8700 Wireless Receiver and HRM product was tested by HAEFELY PESD3010 system that is

certified for IEC 61000-4-2 level 4 for both air and contact ESD tests.

CONFIDENTIAL

Appendix B: HRM8700 Placement Guideline

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The electrical noise generates from the machine could affect the reception range of 5KHZ wireless

receiver. It is better to avoid any noise frequency near 5KHZ or harmonics get near the module.

Although not all electrical noise can be avoided, the following sources could contribute to the

interference. It is recommended to position the HR wireless module as far from these sources as

possible.

 LED display

 Electrical fan

 Audio speaker

 Magnetic field

 Piezo buzzer/beeper

 Magnetic brake (Bike)

 External/ internal CD player

 Excessive ripple noise on power supply

 Switching power supply

 Motor controller

 Sound or noise source in audio band (20HZ~20KHZ)

 Cell phone

An incorrect wireless coil orientation placement will affect the range. The orientation of the receiving

coil on the HRM wireless module should be in horizontal or parallel with the transmitter’s coil to obtain

the optimal performance.

CONFIDENTIAL

The ideal placement location of the HR wireless module would be at the center, toward the front that is

closer to the user, and away from the noise sources.

In case the wireless module has to place off to the left or right side from the center of the console,

then try to keep the offset distance within 12 inches (30cm) or less, otherwiseThe reception distance of

the HRM will be shorten if it is placed too far off from the center.

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CONFIDENTIAL

Order Information

Salutron’s commitment to customer satisfaction is the driving force behind our product

offerings. Contact us to discuss any specific connector options, preloaded features, and

specific application information that you may need.

Life Support Policy

Salutron’s products are not authorized for use as critical components in life support devices or

systems.

Contact Information

SALUTRON, INC.

8371 Central Avenue, Unit A

Newark, CA 94560

Office: 510-795-2876

http://www.salutron.com

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Hardware Revision: PCB8740-4L Rev B

Software Revision: V3302C

Frequency Band(s):

Bluetooth 4.2+BLE:

Frequency Bands:2402-2480 MHz

ANT+:

Frequency Bands:2457 MHz

Transmit Power Range(s):

Bluetooth 4.2+BLE:

Max power:-6.88 dBm

ANT+:

Max power:-3.60 dBm

Modulation Type(s):

Bluetooth 4.2+BLE:

Modulation Mode: GFSK

ANT+:

Modulation Mode: GFSK

Antenna type(s) and Gain(s):

BT&ANT+: Ceramic Antenna, Antenna gain:0 dBi

CE Maintenance

1.EUT Operating temperature range: -10° C to 40° C .

2. Power Rating:

3.The device complies with RF specifications when the device used less

than 20cm from your body.

Declaration of Conformity

Salutron, Inc hereby declares that this Heart rate module is in

compliance with the essential requirements and other relevant provisions

of Directive 2014/53/EU. In accordance with Article 10(2) and Article

10(10),This product is allowed to be used in all EU member states.

FCC Statement

This device complies with part 15 of the FCC Rules. Operation is subject to the following two

conditions:

(1) This device may not cause harmful interference, and

(2) this device must accept

any interference received, including interference that may cause undesired operation.

Any Changes or modifications not expressly approved by the party responsible for compliance

could void the user's authority to operate the equipment.

If the FCC identification number is not visible when the module is installed inside another device,

then the outside of the device into which the module is installed must also display a label

referring to the enclosed module. This exterior label can use wording such as the following:

“Contains Transmitter Module FCC ID: N7P-HRM8700 Or Contains FCC ID: N7P-HRM8700”

When the module is installed inside another device, the user manual of the host must contain

below warning statements;

1. This device complies with Part 15 of the FCC Rules. Operation is subject to the following two

conditions:

(1) This device may not cause harmful interference.

(2) This device must accept any interference received, including interference that may cause

undesired operation.

2. Changes or modifications not expressly approved by the party responsible for compliance

could void the user's authority to operate the equipment.

The devices must be installed and used in strict accordance with the manufacturer's instructions

as described in the user documentation that comes with the product.

Any company of the host device which install this modular with Single modular approval should

perform the test of radiated emission and spurious emission according to FCC part 15C : 15.247

and 15.209 requirement, Only if the test result comply with FCC part 15C : 15.247 and 15.209

requirement，then the host can be sold legally.

The device has been evaluated to meet general RF exposure requirement. The device can be

used in portable exposure condition without restriction.

IC Warning

This device complies with Industry Canada licence-exempt RSS standard(s). Operation is subject

to the following two conditions:

(1) This device may not cause interference, and

(2) This device must accept any interference, including interference that may cause undesired

operation of the device.

Le présent appareil est conforme aux CNR d'Industrie Canada applicables aux appareils radio

exempts de licence. L'exploitation est autorisée aux deux conditions suivantes: (1) l'appareil ne

doit pas produire de brouillage, et (2) l'utilisateur de l'appareil doit accepter tout brouillage

radioélectrique subi, même si le brouillage est susceptible d'en compromettre le fonctionnement

The device has been evaluated to meet general RF exposure requirement. The device can be

used in portable exposure condition without restriction.

Le dispositif a été conçu pour rencontrer le général RF. Le dispositif peut être utilisé dans des

conditions de détention sans effet.

For a host manufacture's using a certified modular, if (1) the module's IC number is not visible

when installed in the host, or (2) if the host is marketed so that end users do not have

straightforward commonly used methods for access to remove the module so that the IC number

of the module is visible; then an additional permanent label referring to the enclosed module:

"Contains Transmitter Module IC: " 10274A-HRM8700 " or "Contains IC: 10274A-HRM8700" must

be used.

Pour un hôte, on utilise un modular, si (1) le numéro de module est non visible

Quand on est installé dans le serveur, or (2) si le propriétaire est commercialisé

Straightforward commonly used for the access to remove travail so that the number IC en vue

Le module est visible;Ensuite, le label permanent a été attribué au module:

"Contient le Module IC:" 10274A-HRM8700" ou "le contenu IC: 10274A-HRM8700" doit être

utilisé.

Salutron HRM8700 Heart rate module User Manual

Salutron Inc. Heart rate module

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