The M1100S WirelessHART Module is a wireless communication module for developing WirelessHART field devices. It is compliant with the HART 7.4 protocol and serves as the core part of a WirelessHART field device.
The M1100S communicates with a customized instrument board through a TTL serial interface and control lines. Together, the module and instrument board form a complete WirelessHART field device. The module supports the mandatory HART commands required for field devices and supports Burst mode.
WirelessHART Communication Module for Field Devices
The M1100S is designed to provide WirelessHART communication functions within a field device.
A typical system consists of the M1100S module and a customized instrument board. The instrument board communicates with the M1100S through a standard TTL serial interface and two control lines. The instrument board also provides the maintenance interface used for module configuration, process monitoring, and related functions.
The M1100S is therefore positioned as a WirelessHART communication module for device manufacturers developing WirelessHART-enabled field instruments.
WirelessHART Module with TTL UART Interface
The M1100S communicates with the instrument board through a standard TTL serial port (UART) and two control lines.
The default serial communication parameters are:
| Parameter | Value |
|---|---|
| Interface | TTL UART |
| Baud rate | 9600 |
| Start bit | 1 |
| Data bits | 8 |
| Parity | Even parity |
| Stop bit | 1 |
The TXD pin is used to send serial data to the instrument board, while RXD receives serial data from the instrument board. RTS indicates a request from the instrument board to send data, and CD indicates that the M1100S is preparing to send data.
M1100S WirelessHART Network Architecture
WirelessHART is a wireless mesh communication protocol developed for process automation applications.
A WirelessHART network includes:
- WirelessHART field devices
- WirelessHART gateway
- WirelessHART network manager
WirelessHART also supports WirelessHART adapters and handheld devices. The network uses the 2.4 GHz ISM band and mesh networking technology.
The M1100S operates as part of the WirelessHART field device and communicates with the instrument board through its local serial interface.
WirelessHART RF Specifications
The M1100S uses the 2.4 GHz band for WirelessHART communication.
| RF Parameter | Specification |
|---|---|
| Frequency band | 2.4 GHz–2.48 GHz |
| Number of channels | 15 |
| Channel separation | 5 MHz |
| Occupied bandwidth | 2.7 MHz |
| Transmission rate | 250 kbps |
| Receiver sensitivity | −102 dBm |
| Output power | 10 dBm |
| Output impedance | 50 Ω |
| Frequency accuracy | −40 ppm to +40 ppm |
These values are specified in the M1100S user manual.
WirelessHART Module Electrical Specifications
The M1100S operates with a supply voltage of 2.7 V to 3.3 V and an operating temperature range of −40°C to +85°C.
The manual specifies relative humidity below 90% and provides current consumption values for transmitting, receiving, and sleep modes.
| Electrical Parameter | Specification |
|---|---|
| Supply voltage | 2.7 V–3.3 V |
| Operating temperature | −40°C to +85°C |
| Relative humidity | <90% |
| Transmitting current | 53 mA (10 dBm) |
| Receiving current | 33 mA |
| Sleep current | 10 μA |
M1100S Communication Between the Module and Instrument Board
The M1100S uses a half-duplex communication mechanism for information exchange with the instrument board.
The interface uses TXD, RXD, RTS, and CD signals.
TXD is the serial data output from the M1100S to the instrument board.
RXD is the serial data input used by the instrument board to send information to the M1100S.
RTS indicates that the instrument board is requesting to send data.
CD indicates that the M1100S is requesting to send data to the instrument board.
When the instrument board sends data to the M1100S, RTS must be pulled low before transmission. The manual specifies a pre-transmission time of 4 ms.
When the M1100S sends data to the instrument board, it pulls CD low before transmission and starts sending preambles. The default number of preambles is 6.
M1100S Data Frame Format
Communication between the M1100S and the instrument board uses a defined UART data frame.
The frame contains:
- Delimiter
- Address
- Command
- Payload length
- Payload
- Checksum
The payload can contain up to 90 bytes. The checksum is 8 bits and is calculated by XORing all data before the checksum field.
The address format can use either a short address or a long address. The short address uses 1 byte, while the long address uses 5 bytes.
WirelessHART Initialization and Normal Operation
After startup, the M1100S enters an initialization phase.
Once internal initialization is complete, the module periodically sends HART Command #0 requests to the instrument board using polling address 0 until it receives a valid response.
The response provides the information required to form the long address of the field device. After receiving the response, the M1100S completes initialization and enters normal operation. The module then uses the long address for subsequent requests.
During normal operation, communication between the M1100S and instrument board can be triggered by:
- HART command requests from the WirelessHART gateway or network manager
- The maintenance interface
- Intra-system communication for synchronizing device information and status
WirelessHART HART Command Support
The M1100S supports HART commands directly within the WirelessHART module.
The manual lists command groups including:
- Burst mode configuration and control
- Event notification
- Mandatory WirelessHART commands
- Standard HART field-device commands
Examples of commands handled directly by the M1100S include:
| HART Command | Description |
|---|---|
| 103 | Write burst period |
| 104 | Write burst trigger |
| 105 | Read burst mode configuration |
| 107 | Write burst device variables |
| 108 | Write burst mode command number |
| 109 | Burst mode control |
| 115 | Read event notification |
| 116 | Write event notification bit mask |
| 117 | Write event notification timing |
| 118 | Event notification control |
| 119 | Event acknowledge |
| 768–976 | Mandatory WirelessHART commands |
The manual states that the M1100S supports WirelessHART commands and Burst mode commands, while commands not supported directly by the module are forwarded to the instrument board.
HART Mandatory Commands
The instrument board is responsible for implementing mandatory HART commands that are not already handled by the M1100S.
The manual lists commands including:
- Command 0 — Read Unique Identifier
- Command 1 — Read Primary Variable
- Command 2 — Read Loop Current and Percent of Range
- Command 3 — Read Dynamic Variables and Loop Current
- Command 6 — Write Polling Address
- Command 7 — Read Loop Configuration
- Command 8 — Read Dynamic Variable Classification
- Command 9 — Read Device Variables with Status
- Command 11 — Read Unique Identifier Associated with Tag
- Command 12 — Read Message
- Command 13 — Read Tag, Descriptor, Date
- Command 14 — Read Primary Variable Transducer Information
- Command 15 — Read Device Information
- Command 16 — Read Final Assembly Number
- Command 17 — Write Message
- Command 18 — Write Tag, Descriptor, Date
- Command 19 — Write Final Assembly Number
- Command 20 — Read Long Tag
- Command 21 — Read Unique Identifier Associated with Long Tag
- Command 22 — Write Long Tag
- Command 38 — Reset Configuration Changed Flag
- Command 41 — Perform Self Test
- Command 42 — Perform Device Reset
- Command 48 — Reset Additional Device Status
- Command 54 — Read Device Variable Information
- Command 59 — Write Number of Response Preambles
- Command 78 — Read Aggregated Commands
- Command 79 — Write Device Variable
- Command 90 — Read Real-Time Clock
- Command 106 — Flush Delayed Response Buffers
WirelessHART Burst Mode
The M1100S supports Burst mode for WirelessHART communication.
Burst messages and event notifications are handled by the M1100S on the WirelessHART network. The manual states that Burst mode is supported on the WirelessHART network and that the M1100S does not have a wired HART interface.
Supported burst messages can include commands #1, #2, #3, #9, #33, #48, as well as specific commands published periodically to the WirelessHART gateway.
The M1100S updates HART command responses automatically based on the configured burst message update period.
WirelessHART Maintenance Interface
The M1100S itself does not provide a dedicated maintenance interface.
According to the manual, the instrument board is responsible for providing the maintenance interface. The interface is used for configuration, including Burst mode configuration and the network configuration required to connect to the WirelessHART network.
The instrument board forwards relevant commands to the M1100S through the maintenance interface.
M1100S Device Status Synchronization
The M1100S supports status synchronization between the WirelessHART module and the instrument board.
The status synchronization mechanism uses HART Commands #64518 and #64520. The M1100S uses Command #64518 to issue a status change indication, while the instrument board uses Command #64520 to send a status update to the M1100S.
The status information includes:
- Device status
- Extended device status
- Standardized status 3
- Configuration changed counter
The module and instrument board maintain corresponding status information and combine local and remote status values as specified in the manual.
WirelessHART Connection Status
The M1100S also provides WirelessHART connection status information to the instrument board.
Whenever the WirelessHART stack changes its operating status, the M1100S sends a HART Command #64519 connection indication to the instrument board. The command contains the current wireless operation mode.
This information can be used by the instrument board to display the WirelessHART operating status or change its own operating mode.
M1100S Diagnostic Information
The M1100S provides a device-specific diagnostic command for reading the received signal level.
HART Command #64600 is used to read diagnostic information. The current implementation supports reading the receive signal level.
The response provides the average received signal level in dBm.
M1100S WirelessHART Power Settings
The M1100S implements HART Command #64525 for reading and writing WirelessHART power settings.
The command includes information such as:
- Power source
- Duration at peak packet load before power drain
- Recovery time from power drain
- Remaining battery life in days
These parameters are exchanged through the command format described in the user manual.
M1100S Write Protection
The module also provides device-specific commands for write protection.
HART Command #64530 can set or clear the M1100S write-protect flag, while HART Command #64531 reads the current write-protect state.
M1100S Pin Configuration
The M1100S provides power, reset, serial communication, and control interfaces.
| Pin | Signal | Description |
|---|---|---|
| 1 | GND | Power ground |
| 2 | VCC | Power supply |
| 6 | RST | Module reset |
| 13 | TXD | Serial data output |
| 14 | RXD | Serial data input |
| 15 | CD | Module data transmission indication |
| 17 | RTS | Instrument board transmission request |
The remaining reserved pins are specified as Do Not Connect in the user manual.
M1100S WirelessHART Module Specifications
| Parameter | Specification |
|---|---|
| Product | M1100S WirelessHART Module |
| Protocol | WirelessHART |
| HART protocol reference | HART 7.4 |
| Supply voltage | 2.7–3.3 V |
| Operating temperature | −40°C to +85°C |
| Relative humidity | <90% |
| Transmitting current | 53 mA at 10 dBm |
| Receiving current | 33 mA |
| Sleep current | 10 μA |
| Frequency band | 2.4–2.48 GHz |
| Number of channels | 15 |
| Channel separation | 5 MHz |
| Occupied bandwidth | 2.7 MHz |
| Transmission rate | 250 kbps |
| Receiver sensitivity | −102 dBm |
| Output power | 10 dBm |
| Output impedance | 50 Ω |
| Frequency accuracy | −40 ppm to +40 ppm |
| Local interface | TTL UART |
| UART baud rate | 9600 |
| Data format | 8 data bits, even parity, 1 stop bit |
M1100S WirelessHART Module FAQ
What is the M1100S?
The M1100S is a WirelessHART communication module designed as the core part of a WirelessHART field device. It communicates with a customized instrument board through a TTL serial interface.
What protocol does the M1100S support?
The manual states that the M1100S is compliant with the HART 7.4 protocol and supports the mandatory field-device commands specified in HART 7.5 as well as Burst mode.
What is the operating frequency of the M1100S?
The specified frequency band is 2.4 GHz to 2.48 GHz, with 15 channels and 5 MHz channel separation.
What is the transmission rate of the M1100S?
The RF transmission rate is 250 kbps.
What is the receiver sensitivity of the M1100S?
The specified receiver sensitivity is −102 dBm.
Does the M1100S support Burst mode?
Yes. Burst mode is supported by the M1100S for WirelessHART network communication.
Does the M1100S have a wired HART interface?
No. The manual states that the M1100S itself does not have a wired HART interface. The instrument board provides the maintenance interface and handles commands not directly processed by the M1100S.
What interface does the M1100S use to connect to an instrument board?
The M1100S uses a TTL UART serial interface together with RTS and CD control signals.
M1100S WirelessHART Module User Manual
For detailed information about the WirelessHART communication architecture, pin assignment, electrical specifications, UART communication, data frame format, HART commands, Burst mode, status synchronization, and application interfaces, refer to the M1100S WirelessHART Module User Manual.
M1100S WirelessHART Communication Module
The M1100S provides the WirelessHART communication functions required for the development of WirelessHART field devices. It combines the WirelessHART network interface with a TTL UART connection to a customized instrument board and supports HART command processing, Burst mode, device status synchronization, and WirelessHART connection status reporting.
For technical information about the M1100S WirelessHART Module, please contact Microcyber.
