Infinite L-com SRTH100-2001-6301 User manual

TEMPERATURE AND HUMIDITY SENSOR
User Manual for SRTH100-2001-6301
Thank you for choosing L-com product. To ensure safe, accurate performance and product
longevity, please take a moment to familiarize yourself with this manual before powering the
device. Please keep it handy for future reference. In case of any questions regarding the
installation or use of product, please call us at 800.341.5266.
M_L-com_SRTH100-2001-6301_05/2022_R1.0
Product Description
The temperature and humidity atmospheric pressure sensors are widely used in environmental
detection, integrating temperature and humidity. The devices can be customized with standard
MODBUS-RTU communication protocol, RS485 signal.
Features
 10 – 30 V wide DC voltage supply
 Standard MODBUS-RTU communication protocol
 Wide range of air pressure range, can be applied to various altitudes
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Technical Indicators
Electrical Connection Method
Notes
 After opening the product packaging, please check the appearance of the product is
intact. Verify the relevant content of the product manual is consistent with the product
 Strictly obey the wiring diagram of the product and work under the excitation voltage of
the product, do not supply over voltage to the product.
 Do not hit / knock the product to avoid damage to the appearance and internal structure
of the ring.
 The product has no self-repair parts for customers, please contact the company in case
of any failure on 800.341.5266.
Supply Voltage 10 ~ 30 VDC
Precision Temperature ±0.5ºC (25ºC)
Relative Humidity ±3% RH (5% RH ~ 95% RH, 25ºC)
Measuring Range Temperature - 40 ºC ~ 80 ºC
Relative Humidity 0% RH ~ 100% RH
Display Resolution Temperature 0.1 ºC
Relative Humidity 0.1% RH
Long-Term Stability Temperature 0.1 ºC/y
Relative Humidity 0.1% RH/y
Operating Temperature -20 ~ 60 ºC
Storage Temperature -40 ~ 100 ºC
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Parameter MODBUS Hold Register Address (16-bit)
Temperature
Address: 0000H
The temperature data is uploaded in the form of a complement. The
value of the reading is divided by 10 to obtain the measured value of
the temperature.
For example, the reading value is 0xFF9B and the decimal value is
-101, the measured value of the temperature is -10.1 °C.
Relative Humidity
Address: 0001H
The measured value of the relative humidity can be obtained by
dividing the value by 10. For example, if the reading value is 0x0149
and the decimal value is 329, the measured value of relative humidity is
32.9% RH.
Baud Rate
Address: 0014H
The setting values are 48, 96, 192, 384, 576, and 1152, corresponding
to baud rates of 4800, 9600, 19200, 38400, 57600, and 115200.
For example, the default baud rate is 9600 and the setting value is
0x0060.
Check Digit
Address: 0015H
0x0000 means no parity, 0x0001 stands for odd parity, 0x0002 stands
for even parity
Slave Address Address: 0017H Default: 0x0001
Common Problems and Solutions
Possible reasons when the device is not getting connected to a PLC or computer:
 The computer has multiple COM ports and the selected port is incorrect.
 The device address is incorrect or has duplicate address (all factory defaults are 1).
 Errors like baud rate, check mode, data bit, stop bit error.
 The host polling interval and the waiting response time are too short and need to be set to
more than 200ms.
 The RS485 bus is disconnected or the A and B lines are reversed.
 Number of devices is too many or the wiring is too long. The power supply outlet should be
nearby. Add RS485 booster and increase the 120Ω terminating resistor.
 The USB to RS485 driver is not installed or damaged.
 The equipment is damaged.
Temperature and Humidity Sensor (RS485) MODBUS Communication
Protocol
The basic settings of the communication protocol:
 Transmission mode: MODBUS-RTU mode.
 Communication parameters: Default baud rate is 9600bps (optional 4800bps, 9600bps,
19200bps, 38400bps, 57600bps, 115200bps, can be configured according to user
requirements). 1 start bit, 8 data bits, no parity (optional odd parity), even parity, 1 stop bit.
After changing the communication parameters, power ON the sensor again.
 Slave address: The factory default is 1 and can be configured according to user
requirements.
Keep the register list
MODBUS RTU Instruction
Supported MODBUS function codes: 0x03, 0x06
Example of 03H function code: Read the temperature measurement data of the sensor with
slave address 1.
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Host Query Command
Slave Address 01H Slave Address
Function 03H Function code
Byte Count 02H 2 bytes in length
Data Hi 00H The temperature at this time is: 24.7 ° C
Data Lo F7H The temperature at this time is: 24.7 ° C
CRC Check Lo F9H CRC check code low 8 bits
CRC Check Hi C2H CRC check code high 8 bits
Slave Address 01H Slave Address
Function 03H Function code
Starting Address Hi 00H Start register address is 8 bits high
Starting Address Lo 00H Start register address is 8 bits low
No. of Registers Hi 00H The upper 8 bits of the number of registers
No. of Registers Lo 01H The lower 8 bits of the number of registers
CRC Check Lo 84H CRC check code low 8 bits
CRC Check Hi 0AH CRC check code high 8 bits
Response
Example of 06H function code: Modify the baud rate (this example is modified to 57600bps).
Host Query Command
Slave Address 01H Slave Address
Function 06H Function code
Starting Address Hi 00H The baud rate holding register address is 0014H
Starting Address Lo 14H Baud rate holding register address is 0014H
Data Hi 02H Baud rate is 57600 bps, the value of the register
is 576, which is 0x0240
Data Lo 40H Baud rate is 57600 bps, the value of the register
is 576, which is 0x0240
CRC Check Lo C9H CRC check code low 8 bits
CRC Check Hi 5EH CRC check code high 8 bits
Response
Slave Address 01H Slave Address
Function 06H Function code
Starting Address Hi 00H The baud rate holding register address is 0014H
Starting Address Lo 14H Baud rate holding register address is 0014H
Data Hi 02H Baud rate is 57600 bps, the value of the register
is 576, which is 0x0240.
Data Lo 40H Baud rate is 57600 bps, the value of the register
is 576, which is 0x0240.
CRC Check Lo C9H CRC check code low 8 bits
CRC Check Hi 5EH CRC check code high 8 bits
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