AH500 Module Manual 5.1.7 Functions 1. Enabling/Disabling a channel A temperature received from a two-wire/four-wire sensor is converted into a digital value at a speed of 150 ms a channel, and a temperature received from a three-wire sensor is converted into a digital value at a speed of 300 ms a channel. If a channel is not used, users can disable it to decrease the total conversion time. 2. Temperature unit Users can select the degree Celsius (°C) or the degree Fahrenheit (°F) as a unit of measurement for temperature. 3. Calibration To make a curve meet actual needs, users can calibrate the curve by changing an offset and a gain.
A calibration range depends on a range of inputs which can be received by hardware. The range of offsets used for calibration is -1.0~1.0, and the range of gains used for calibration is 0.9~1.1. Example 1: The temperatures -100 ℃~ 100℃ correspond to the digital values -100~100. The original signals are used. The gain is 1, and the offset is 0. The temperature received by the channel is 0 ℃ , and the digital value is -1. The temperature received by the channel is 100 ℃ , and the digital value is 99. Users can calibrate the channel by calibrating the gain and the offset. The users can get the gain for the calibration by means of the equations below.
Gain=(Y2-Y1)/(X2-X1)=[99-(-1)]/(100-0)=1 Gain used for calibration=1/Gain=1/1=1 The users can get the offset for the calibration by means of the equations below. Offset=Y1=-1 Offset used for calibration=1-Y1=1 5-6 Item Function Description 1 Enabling/Disabling a channel 1. Users can enable or disable a channel. 2. If a channel is disabled, the total conversion time is decreased. 2 Temperature unit Users can select the degree Celsius (°C) or the degree Fahrenheit (°F) as a unit of measurement for temperature. 3 Calibration Users can calibrate a linear curve. 4 Average Conversion values are averaged and filtered.
5 Disconnection detection When a sensor is disconnected, AH04PT-5A gives an alarm or a warning. 6 Channel detection If an input signal exceeds a range of inputs which can be received by hardware, the module will give an alarm or a warning. a. Warning LED indicator: When a warning occurs, the ERROR LED indicator blinks or does not blink. b. Interrupt: An interrupt service routine is enabled. 7 PID control An object can be maintained at a desired temperature through a PID control action.