Greystone Energy Systems, Inc. 150 English Drive, Moncton, NB E1E 4G7 Canada Tel: +1-506-853-3057 Tollfree (North America): +1-800-561-5611 Fax: +1-506-853-6014
Email: [email protected] Web: www.greystoneenergy.com
0x03 --- Read TEMPERATURE_VALUE
Query
Slave address
(0x01 to 0xFF)
0x03
0x00
0x00
0x00
0x01
CRC
LSB
CRC
MSB
Response
Slave address
(0x01 to 0xFF)
0x03
0x02
Register value
MSB
Register value
LSB
CRC
LSB
CRC
MSB
* Register value = 0xFE70 to 0x03E8, corresponding to -40.0 to 100.0 °C (multiplier = 10)
or = 0xFE70 to 0x0848, corresponding to -40.0 to 212.0 °F (multiplier = 10)
The temperature value is either in °C (default) or °F depending on the value of the TEMPERATURE_UNITS register.
This register has a multiplier of 10, the application must divide by 10 to obtain the correct value.
0x03 --- Read RELATIVE_HUMIDITY_VALUE
Query
Slave address
(0x01 to 0xFF)
0x03
0x00
0x01
0x00
0x01
CRC
LSB
CRC
MSB
Response
Slave address
(0x01 to 0xFF)
0x03
0x02
Register value
MSB
Register value
LSB
CRC
LSB
CRC
MSB
* Register value = 0x0000 to 0x03E8, corresponding to 0 to 100 %RH (multiplier = 10)
This register has a multiplier of 10, the application must divide by 10 to obtain the correct value.
0x06 --- Write TEMPERATURE_OFFSET
Query
Slave address
(0x01 to 0xFF)
0x06
0x00
0x02
Register
Value MSB
Register
value LSB
CRC
LSB
CRC
MSB
Response
Slave address
(0x01 to 0xFF)
0x06
0x00
0x02
Register
Value MSB
Register
value LSB
CRC
LSB
CRC
MSB
* This register is used to add or subtract an offset to the temperature value if necessary to conform to a local reference.
Register value = 0xFFF6 to 0x000A for -10 to 10
For °C operation, this corresponds to T_OFFSET / 2 = -5.0 to 5.0 °C. ie: 0x0003 => 3/2 = +1.5 °C offset.
For °F operation, this corresponds to T_OFFSET = -10 to 10 °F. ie: 0x0003 => 3 = +3 °F offset.
The operating temperature units (°C or °F) for the device should be selected first, and then add any offset if necessary.
The RTU function codes supported by the RH/T sensor are shown below.
