Delta Uno Lite Modbus User Guide

DELTA uno Lite Modbus

Revision

Overview

UNOlite is an indoor air quality monitor to measure the space temperature / humidity / CO2 / PM2.5 / PM10 / PM1 / TVOC and expose the measurements directly onto a BACnet MS/TP or Modbus RTU network. Moreover, the measurements are also accessible with UNO apps through BLE or UNO web through Wi-Fi (Wi-Fi model). Please refer to UNOlite official website for more information. This document is primarily concerned how to add UNOlite to Modbus/RTU network.

Hardware Interface

Buttons 

NOTE: /t’s recommended to use a paper clip to press the keys.

Terminal block 

DIP switch 

NOTE The dips should be adjusted to proper position in power off state. Adjust the dips, then power on device.

Modbus Mode
UNOlite follows Modbus over serial line specification and will run on Modbus/RTU mode if the 7th pin is set to OFF state. The definition of the dips in Modbus mode as listed below:

• NOTE: The definitions of dip are different from Modbus mode. Please make sure which mode is chosen.
• NOTE: Pin6 is not defined in Modbus mode

Serial Configuration

UNOlite can directly connect to a controller with RS485 interface, up to 32 UNOlite devices can be joined to a Modbus serial bus.

NOTE: Suggestion to use 22AWG shielded twisted pair cable to connect devices in sequence

Default Serial Configuration: 

• Baud: 9600
• Data-Bit: 8
• Parity: None
• Stop-Bit: 1

Note: perform factory reset to restore default value if the configuration is missing

Modbus Slave Address
The DIP pins 1~5 represent for binary number 0~31, pin 1 is most significant bit (MSB) and pin 5 is least significant bit (LSB). Notice that Modbus slave address starts from 208, therefore, UNOlite can be configured address from 208 to 239:

Modbus Slave Address Table 

Modbus Read Data

UNOlite supports function code both 0x03 and 0x04 to read following registers

• 0x03: read holding registers
• 0x04: read input registers
  

  Request
  Slave Address 1 byte	Function code 1 byte	Register 2 bytes	Length [N] 2 bytes	CRC16 2 bytes
  Response
  Slave Address 1 byte	Function code 1 byte	Count [2*N] 1 byte	Data N * 2 bytes	CRC16 2 bytes

  Sensor Measurement
  Register		Name	Description
  30001	0x0000	IAQ index	Give an index according to current PM2.5, PM10, and CO2 concentration. The index also be referenced by IAQ LED: GREEN: 0~80 YELLOW: 81~100 RED: 101~400 PURPLE: 401~
  30002	0x0001	Concentration of PM2.5	Unit: μg/m3
  30003	0x0002	Concentration of PM10	Unit: μg/m3
  30004	0x0003	Concentration of carbon dioxide (formula CO2)	Unit: ppm
  30005	0x0004	Concentration of total volatile organic compound (TVOC)	Unit: ppb
  30006	0x0005	Concentration of total volatile organic compound (TVOC)	Unit: μg/m3 (factor 1 ppb = 4.5 μg/m3)
  30009	0x0008	Humidity	Unit: 0.01%
  30011	0x000A	Celsius temperature	Real Temp = (Value – 4500) * 0.01 Unit: °C
  30018	0x0011	Fahrenheit temperature	Real Temp = (Value – 4500) * 0.01 Unit: °F

  30020

  0x0013

  Concentration of PM1

  Unit: μg/m3

  Sensor State
  Register		Name	Description
  30033	0x0020	PM2.5 sensor	State of sensor hardware module 0x0000: Power off or does not exist 0x0001: Sensor Ready 0x0002: Warming up 0x0003: Busy 0x00FE: CSERROR 0x00FF: FAIL
  30034	0x0021	PM10 sensor
  30035	0x0022	CO2 sensor
  30036	0x0023	TVOC sensor
  30037	0x0024	Humidity sensor
  30038	0x0025	Temperature sensor
  30042	0x0029	PM1 sensor
  30044	0x002B	IAQ LED state	0x0000: LED off 0x0001: LED on

  Device Information
  Register		Name	Description
  30145	0x0090- 0x009F	Model and Product Serial Number	An ASCII string consists model name and serial number, separated by a comma. For example: “UNO-L,2250L01F9999”
  30209	0x00D0	Main firmware version	Number 1 to 65535 0x0000: device is initializing
  30257	0x0100- 0x0102	BT MAC address	6 groups of two hexadecimal digits, e.g. F2:11:8F:36:F6:93
  30260	0x0103- 0x0105	WIFI MAC address	6 groups of two hexadecimal digits

Modbus Write Command

UNOlite supports function code 0x06 and 0x10 to write request

0x06: write single register

0x10: write multiple registers

Modbus Examples

1. Read all sensor status from device 208 (0xD0)
   

   Request	D0 03 00 20 00 0B 17 86
   Response	D0 03 16 00 01 00 01 00 01 00 01 00 01 00 01 00 FE 00 FE 00 FF 00 00 00 01 60 8F

2. Read firmware version from device 208 (0xD0)
   

   Request	D0 03 00 D0 00 01 97 B2
   Response	D0 03 02 00 04 45 95

3. Set rs485 serial configuration, 115200-8-N-1
   

   Request	D0 10 00 60 00 03 06 00 01 C2 00 84 00 BB 56
   Response	D0 10 00 60 00 03 92 57

Modbus Exception Response

If device receives a request message without a communication error, but cannot handle the query. It will reply with requested function code plus 0x80. Example, function code 0x3 becomes 0x83

Response format 

Code list 

Note: Please refer to “ModbUs Application_Protocol_V1_1b3” from www.modbus.org

References

• The Modbus Organization
• The Modbus Organization