MBMap Registry
  1. Devices
  2. Novus
  3. NP785

Novus NP785 Modbus register map

Also covers NP785-50, NP785-100, NP785-05, NP785-20, NP785-68, NP785-400, NP785-1000

Ultra-low differential pressure transmitter (±50 Pa to ±1000 mbar) with 4-20 mA / 0-10 V output, one alarm output and Modbus RTU over RS485: pressure, min/max, unit, filter, offset and autozero, output, alarm, forcing and diagnostics

  • Official
  • 57 registers
  • Modbus RTU
  • Revision 1 · 2026-10-31
  • Identity: model

Official: Written from the manufacturer's documentation, but not tested on a device yet. Check the map against the manufacturer's documentation before you write to a live device. Tested it? Report a test.

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Communication

Protocol
Modbus RTU
Unit ID
1
Serial
19200 8N1 · 19200 baud, 8 data bits, none parity, 1 stop bit
Byte / word order
CDAB · bytes big-endian, words low first (word swap)
Addresses
0-based

Connection values are defaults: the device may be configured differently.

Map

Registers
57 holding registers
Groups
9
Translation tables
5
Revision
1 · 2026-10-31
Firmware
from 2.1 V2.1x or later
Added
()
File
maps/novus/np785.mbmap.json · 14 KB · history
SHA-256
8b79768db59749fc853db0618141a87fd70267e66469f2026b2ec227c0c9dc3c
Manufacturer
novus.com.br

Device identity

What a tool can read to check that this map fits the connected device (SPEC.md section 4.7). Registers with a role are read like any other register.

Registers
RoleRegisterAddressTypeValues
Model Sensor type holding 100 uint16 0 = NP785-05, 1 = NP785-20, 3 = NP785-68, +5 more

Sources and notes

Source: Novus NP785 instruction manual V2.1x (Portuguese), chapter 7

  • Functions 03, 05, 06 and 16; writes with address 0 are broadcast.
  • Serial defaults: address 1, 19200 bit/s, no parity (registers 137-139). The manual does not give the stop bits; 1 is assumed.
  • 32-bit values take two registers, low word first (HR_PRESS at 0, HR_PRESS_H at 1). The manual says the floats are 'little-endian with byte inversion'; this map reads them with the low word first and big-endian bytes in each word. Both registers of a 32-bit value must be read or written together.
  • The integer pressure registers carry the decimal places of the selected unit (mbar 3, mpsi 2, inH2O 3, mmH2O 2, Pa 1), so they have no fixed scale; the float registers 6-11 give the value directly.
  • Settings that take a pressure are written to an input register pair (103-106, 157-158, 179-185, 142-143); when the value is in range the device copies it to the working pair (108-111, 159-160, 186-194, 144-145). Out-of-range inputs are flagged in register 343.
  • Sensor type 9 (5 mbar) needs firmware V2.1x or later.
  • Written from the manufacturer's manual; not tested on a device.
AreaAddressNameTypeAccessUnitScaleDescription
HR 6 float32 CDAB R In the selected unit (register 115)
HR 8 float32 CDAB R
HR 10 float32 CDAB R
HR 0 int32 CDAB R Integer with the decimal places of the selected unit: mbar 3, mpsi 2, inH2O 3, mmH2O 2, Pa 1
HR 2 int32 CDAB R Integer with the decimal places of the selected unit: mbar 3, mpsi 2, inH2O 3, mmH2O 2, Pa 1
HR 4 int32 CDAB R Integer with the decimal places of the selected unit: mbar 3, mpsi 2, inH2O 3, mmH2O 2, Pa 1
HR 161 uint16 RW Write 1 to reset every minimum and maximum
HR 100 uint16 R
HR 115 uint16 RW Changing it resets the retransmission limits to the operating limits
HR 113 uint16 RW s Time constant of the first-order filter
HR 359 int32 CDAB R The manual does not give the data type of this pair; read here as a 32-bit integer like the pressure in register 0
HR 361 int32 CDAB R The manual does not give the data type of this pair; read here as a 32-bit integer like the pressure in register 0
HR 142 float32 CDAB RW Within ±20 % of the range; the device copies it to register 144 when valid
HR 144 float32 CDAB R
HR 147 uint16 RW
HR 148 uint16 RW Write 1 to zero the reading
HR 149 float32 CDAB R
HR 101 uint16 RW
HR 103 int32 CDAB RW The manual does not give the data type of this pair; read here as a 32-bit integer like the pressure in register 0; the device copies it to register 108 when valid
HR 105 int32 CDAB RW The manual does not give the data type of this pair; read here as a 32-bit integer like the pressure in register 0; the device copies it to register 110 when valid
HR 107 uint16 RW
HR 108 int32 CDAB R The manual does not give the data type of this pair; read here as a 32-bit integer like the pressure in register 0
HR 110 int32 CDAB R The manual does not give the data type of this pair; read here as a 32-bit integer like the pressure in register 0
HR 178 uint16 RW
HR 179 int32 CDAB RW The manual does not give the data type of this pair; read here as a 32-bit integer like the pressure in register 0; the device copies it to register 191 when valid
HR 181 int32 CDAB RW The manual does not give the data type of this pair; read here as a 32-bit integer like the pressure in register 0; the device copies it to register 193 when valid
HR 183 uint16 RW
HR 184 int32 CDAB RW The manual does not give the data type of this pair; read here as a 32-bit integer like the pressure in register 0; up to 20 % of the range
HR 186 int32 CDAB R The manual does not give the data type of this pair; read here as a 32-bit integer like the pressure in register 0
HR 188 uint16 RW s
HR 189 uint16 RW s
HR 190 uint16 RW
HR 191 int32 CDAB R The manual does not give the data type of this pair; read here as a 32-bit integer like the pressure in register 0
HR 193 int32 CDAB R The manual does not give the data type of this pair; read here as a 32-bit integer like the pressure in register 0
HR 152 uint16 RW
HR 153 uint16 RW 0.00-10.00 V or 3.60-21.00 mA; the manual does not give the encoding
HR 154 uint16 RW
HR 155 uint16 RW
HR 156 uint16 RW
HR 157 int32 CDAB RW The manual does not give the data type of this pair; read here as a 32-bit integer like the pressure in register 0; the device copies it to register 159 when valid
HR 159 int32 CDAB R The manual does not give the data type of this pair; read here as a 32-bit integer like the pressure in register 0
HR 341 bool bit 0 R
HR 341 bool bit 1 R
HR 341 bool bit 3 R
HR 341 bool bit 5 R
HR 341 bool bit 10 R
HR 341 bool bit 12 R
HR 342 bool bit 0 R
HR 343 bool bit 1 R
HR 343 bool bit 3 R
HR 343 bool bit 6 R
HR 344 bool bit 1 R
HR 344 bool bit 2 R
HR 137 uint16 RW
HR 138 uint16 RW
HR 139 uint16 RW
HR 166 string[10] RW Up to 20 characters, first character in the low byte

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