A70H-TL-P

The A70H-TL-P is a precision thermistor temperature sensor. The sensor is compact and easy to install, with good linear response, strong load capacity, long transmission distance and resistance to interference.

Output Characteristics

Current
Characteristic Transfer Function
T=(I-4)/(20-4) *Scale range + offset

(where T – temperature (^oC), I = output current (mA)), offset = range start point

Example:             (11.5mA – 4mA)/(20mA – 4mA) * 150°C + (-50°C) = 20.3°C

Voltage
Characteristic Transfer Function
T=U/(full scale voltage-zero point voltage) *Scale range
(where T = temperature (^oC), U = output voltage (V)

RS485
If the transmission distance is over 100m, add one 120Ω terminal matching resistance on the front end and back end of bus interface respectively.

Communication Protocol (MODBUS)
Transmission mode: MODBUS-RTU, Baud rate: 9600bps, Data bits: 8, Stop bit: 1, Check bit: no
Slave address: factory default is01H (set according to need, 00H, FFH)

The 03H Function Code Example: Read the Temperature
Host Scan Order (slave address: 0x01)
01 03 00 00 00 01 840A

Slave Response
01 03 02 00 B4 B833

Temperature:(00B4)H=(180)D,180/10=18(^oC)

The 10H Function Code Example: Modify the slave address
Host Scan Order (Changed to 01H, read and write address must be 00H):
00 10 01 BDC0

Slave Response:
00 10 007C

The 20H Function Code Example: Read the Slave Address (fixed command, ensure that no other devise are on the bus)
Host Scan Order:
00 20 00 68

Slave Response (addr.=01H):
00 20 01  A9C0

*Note: All underlined are fixed bits;
The last two bytes are CRC check command.