HM29 Digital Intelligent Pressure Transmitter

The HM29 uses fully digital RS485/RS232/USB output instead of analog 4-20mA signals. This means the pressure data is transmitted digitally with 20-bit resolution, eliminating analog-to-digital conversion errors. The built-in microprocessor also provides advanced features like zero-point automatic stability tracking (ZSC), temperature self-compensation (TSC), and configurable sampling rates — capabilities that analog transmitters simply cannot offer. Additionally, the RS485 bus supports up to 63 sensors on one loop, dramatically reducing wiring costs.

The HM29 offers four accuracy grades: ±0.25% FS (standard industrial), ±0.1% FS (precision process control), ±0.075% FS (high-precision applications), and ±0.05% FS (laboratory/reference grade). For general industrial monitoring, ±0.25% FS is typically sufficient. Process control in chemical and power plants usually requires ±0.1% FS. Research, calibration, and metrology applications benefit from ±0.05% FS. Consider your measurement uncertainty budget and select one grade better than your minimum requirement.

Yes. The HM29 is available with optional intrinsically safe certification (Ex ia IIC T5) by selecting code ‘E’ in the ordering guide. When installed with an approved safety barrier, it is rated for use in Zone 0, 1, and 2 hazardous areas where flammable gases or vapors may be present. This makes it suitable for oil refineries, chemical plants, and gas processing facilities.

Up to 63 HM29 sensors can be connected on a single RS485 serial bus loop using standard MODBUS RTU protocol. Each sensor is assigned a unique address (1-63) and communicates at configurable baud rates from 1200 to 230400 bps. For optimal performance in multi-sensor installations, we recommend using 9600 or 19200 bps with proper bus termination resistors at both ends of the RS485 line.

The HM29 comes with free companion PC software that connects via USB, RS232, or RS485 interface. The software allows you to configure measurement parameters, set zero and span values, select pressure units, adjust sampling rates, and read real-time pressure and temperature data — all without requiring a HART communicator or hand-held terminal. For custom integration, the HM29 supports standard MODBUS RTU and ASCII communication protocols, compatible with LabVIEW, MATLAB, Python, and virtually any DAQ platform.

Standard configurations typically ship within 2-3 weeks from order confirmation. Custom pressure ranges within the -100 kPa to 100 MPa envelope, special process connections, flush diaphragm versions, and extended cable lengths are available with 3-4 week lead times. Volume orders (50+ units) may qualify for expedited production. Contact our sales engineering team at sales@hammok-tech.com for detailed quotations and lead time confirmation.