HMT-112 – HART Gateway (HART to MODBUS Converter)
Short description: A rugged DIN-rail mounted HART to MODBUS gateway that accepts up to 15 HART slave inputs and converts their process variables into fixed MODBUS registers. Provides isolated HART port, RS485 MODBUS output, and LED diagnostics for SCADA integration.
No serial information available.
Key Features
- Rugged, microcontroller-based DIN rail mount system.
- Accepts HART inputs from up to 15 slave devices.
- Converts HART variables into fixed MODBUS address registers (no configuration required).
- Provides floating-point values of Primary, Secondary, Third, and Fourth variables from each HART slave.
- Engineering units automatically mapped from HART slaves.
- Device information such as ID, manufacturer’s code, hardware and software version available via MODBUS.
- HART slave status available in MODBUS registers.
- User-selectable baud rate via DIP switch (9600, 19200, 38400, 57600).
- Station ID selectable from 1 to 64.
- LED indications for MODBUS Tx/Rx, system OK, and HART Tx/Rx/CD for easy diagnostics.
- Isolated HART port for reliable communication.
- Ideal for SCADA/DCS applications.
Technical Specifications
- Mounting: DIN rail mount; ABS molded box
- Dimensions: 75 × 45 × 110 mm (H × W × D)
- Supply: 24 VDC ±10%
- Connections: Screw-type for supply, RS485, and HART input
- Communication: MODBUS RTU over RS485 (master side); HART on slave side
- Baud Rates: Selectable 9600, 19200, 38400, 57600 via 8-way DIP switch
- Station ID: Configurable 1–64
- No. of Slaves: Up to 15 HART slave units
- Outputs: Floating point values of 4 HART variables per slave (Primary to Fourth)
- Additional Data: Engineering units, device ID, manufacturer code, HW/SW version, and HART slave status in MODBUS registers
- LED Indications: OK (system), Tx/Rx (MODBUS), Tx/Rx/CD (HART)
Support Videos
Installation Guide
Troubleshooting
Downloads
Frequently Asked Questions (FAQs)
What is the HMT112 used for?
The HMT112 is a HART (slave side) to MODBUS RTU (master side) protocol converter. It translates data from up to 15 HART slave devices into MODBUS floating-point registers.
What supply voltage is required?
The unit operates on 24VDC (range 10–28VDC). Ensure it’s isolated from the HART slave device’s 24VDC supply.
How many HART devices can it support?
It supports up to 15 HART slave units in multi-drop configuration with poll addresses 1–15.
What are the LED indications?
SYS shows system health; RTx/RRx indicate MODBUS communication; HTx/HRx/CD indicate HART communication activity.
How are baud rate and station ID set?
Both are configured via DIP switches. DIP 1–2 set baud rate (9600–57600 bps), DIP 3–8 set station ID (1–64).
How does it handle polling of HART devices?
It automatically polls addresses 0–15, stores active devices, and retries 5 times before marking a device as inactive.
What MODBUS data does it provide?
It provides loop current, up to four HART variables, their engineering units, and device details (ID, version, manufacturer code, etc.).
How to add a new HART device?
Connect the new device, assign it a unique poll address, and reset the HMT112 (either via power cycle or writing to MODBUS address 40341).
What precautions should be taken?
Ensure unique poll IDs, proper grounding, use a 270Ω (or manufacturer-recommended) resistor in the loop, and verify each transmitter’s voltage range.
Need More Help?
Call us at +91-20-24479210 or email scan@vsnl.com