Chapter 2 Analog Input Module AH04AD/AH08AD 2.2.5 Functions HWCONFIG, built-in utility software in ISPSoft, can be used to set a module. Users can set modes and parameters by means of HWCONFIG. 1. Enabling/Disabling a channel An analog signal is converted into a digital signal at a speed of 150 μs a channel. The total conversion time is 150 μsЧ(the number of channels). If a channel is not used, users can disable it to decrease the total conversion time. 2. 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.
A volt is a unit of calibration for offsets if inputs received are voltages. A milliampere is a unit of calibration for offsets if inputs received are currents. 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 inputs received by a channel are voltages in the range of -10.0 V to +10.0 V. The original signals are used. The gain is 1, and the offset is 0. The voltage received by the channel is 0 V, and the digital value is -0.05. The voltage received by the channel is 10.0 V, and the digital value is 9.95. 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)=[9.95-(-0.05)]/(10-0)=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= -0.05 Offset used for calibration=0-Y1=0.05 2-7 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 Calibration Users can calibrate a linear curve. 3 Average Conversion values are averaged and filtered. 4 Scale range An analog range corresponds to a digital range.
5 Disconnection detection Only if the analog rang is 4 mA~20 mA or 1 V~5 V does the disconnection detection function. 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.