Moire Labs MODBUS Protocol Version 1
Please mind, that not all registers are supported on all device types.
Accessing RAM
READ function 0x03 (words) / 0x46 (bytes)
WRITE function 0x06 (words) / 0x47 (bytes)
Using functions 0x03 and 0x06 reads and writes MODBUS address in word-lengths (2 bytes). This means, that defining MODBUS register to read must always be even. On the other hand, functions 0x46 and 0x47 reads and writes data in byte-lengths (1-byte), which makes it more flexible to access data which would otherwise be padded. The following tables show both register addresses - either accessible through word address or byte address.
Fnc 0x03/0x06 Fnc 0x46/0x47 Description Value type
address [DEC] address [DEC]
0 0 Filtered value of primary ADC (RO) 32bit float
2 4 Filtered value of secondary ADC (RO) 32bit float
4 8 Output DAC (RO) 16bit int
5 10 Raw primary value without correction (RO) 32bit float
7 14 Raw secondary value (RO) 32bit float
9 18 Primary measurement value (RO) 32bit float
11 22 Secondary measurement value (RO) 32bit float
13 26 Output value (RO) 32bit float
17 34 Primary value without autozero correction (RO) 32bit float
55 measurement_interval_hours (RW) uint8_t
28 56 measurement_interval_minutes (RW) uint8_t
57 measurement_interval_seconds (RW) uint8_t
RO denotes read-only register, RW denotes read-write register.
Accessing ROM / EEPROM
READ function 0x41 (words) / 0x44 (bytes)
WRITE function 0x42 (words) / 0x45 (bytes)
Using functions 0x41 and 0x42 reads and writes MODBUS address in word-lengths (2 bytes). This means, that defining MODBUS register to read must always be even. On the other hand, functions 0x44 and 0x45 reads and writes data in byte-lengths (1-byte), which makes it more flexible to access data which would otherwise be padded. The following tables show both register addresses - either accessible through word address or byte address.
Fnc 0x41/0x42 Fnc 0x44/0x45 Description Value type
address [DEC] address [DEC]
0 0 Protocol (0:MODBUS RTU; 1:SDI12) (RW) uint8_t
1 Databits (0:5, 1:6, 2:7, 3:8) (RW) uint8_t
1 2 Parity (0:none, 1:even, 2:odd) (RW) uint8_t
3 Stopbits (0:1, 1:2) (RW) uint8_t
2 4 Baud rate (in baud/s) (RW) uint32_t
4 8 MODBUS address (RW) uint8_t
121 Primary reading minimum (RO) 32bit float
125 Primary reading maximum (RO) 32bit float
14561 Scale factor of primary reading (RO) uint8_t
7281 14562 Unit of primary reading (RO) uint8_t
14563 Scale factor of secondary reading (RO) uint8_t
7282 14564 Unit of secondary unit (RO) uint8_t
7362 14724 Location ID (RW) uint16_t
7363 14726 Sensor ID (RO) uint32_t
7365 14730 Measurements per packet (RW) uint8_t
7368 14736 Primary measurement type (RO) uint8_t
7369 14738 Measurement ID (RW) uint8_t
RO denotes read-only register, RW denotes read-write register.
Units of measurements and scale factors lookup tables
Units
K (temperature) = 0 °C (temperature) = 1 °Re (temperature) = 2 °F (temperature) = 3 °R (temperature) = 4 Pa (pressure) = 5 bar (pressure) = 6 atm (pressure) = 7 torr (pressure) = 8 mmHg (pressure) = 9 psi (pressure) = 10 m (level) = 11 reserved = 12 m3 (volume) = 13 l (volume) = 14 m3/s (flow) = 15 m3/h (flow) = 16 l/s (flow) = 17 l/h (flow) = 18 A (current) = 19 V (voltage) = 20 % (humidity) = 21
Unit scale factors
This is the unit scale factor. For example, if the unit is Pa and the scale factor is KILO, then the reading is in kPa.
no scale factor = 0 a (atto) = 1 f (femto) = 2 p (piko) = 3 n (nano) = 4 u (mikro) = 5 m (mili) = 6 c (centi) = 7 d (deci) = 8 da (deka) = 9 h (hekto) = 10 k (kilo) = 11 M (Mega) = 12 G (Giga) = 13 T (Tera) = 14 P (Peta) = 15 E (exa) = 16