Delta DTM Series - DTM Input Filtering and Error Handling

Chapter 3: Input Function Configuration
DTM temperature controller operating manual
3-4
3.1.4 Analog Input (Voltage, Current) Applications
When input channels are chosen as having analog voltage or current input, the selected analog input type
and range should correspond to the input upper and lower limits of the setting range; After the input
measures an analog signal, the system will compare with the setting range before converting the
corresponding displayed input value.
Example: If the input channels is chosen to measure [0~5V analog input ] signal in accordance with the
default range between the SV upper and lower limits is
[-1999~19999]; the next step is to make the upper
SV setting [5000], and the lower SV setting [0]. If the input sensor measures input voltage as [2.5V], the
corresponding PV value will be [2500].
According to the calculation formulas listed above:
PV value = (upper limit of SV value -Lower limit of SV value) * (measured input value - analog input lower
limit) / (upper limit of analog input - analog input lower limit)+ lower limit of SV value.
PV = (5000 - 0) x (2.5 - 0.0) / (5.0 - 0.0) + 0 = 2500
3.2 Temperature Filter and Input Error Setting
3.2.1 Temperature Filter Setting
Because the input signal may be subject to interference from noise, causing the displayed value to be
unstable, this device provides a temperature filter function, which has two parameters that users can set.
One is the temperature filter factor, which has a setting range of 0-50, where 0 is no filter; the default value
is 8. The greater this value, the stronger the filtering effect; and the slower the displayed input value will
appear. The other parameter is the temperature filter range, which has a setting range of 1~100, with units
consisting of 0.1°C; the default value is 10 (1.0°C), which indicates that input signal noise within 1.0°C will
activate the filter. The setting range can be increased when the fluctuations in input noise are large.
Adjustments are explained as follows:
A. Digital filtering factor: Adjustment range: 0~50
The calculation formula is: Displayed value = (previous displayed value * n + current present
value) / (n+1)
B. Digital filtering range: Adjustment range: 1~100, units: 0.1°C (only applicable when the input
sensor type is TC or RTD)
3.2.2 Input Error Setting
Temperature control applications may encounter the problem of temperature difference when the
temperature at the measurement location and at the sensor location are different. This device needs
customers needs by providing users with the ability to set an input error offset value and gain value.
Adjustments are explained as follows:
A. Offset: Setting range:
-999~9999, units: 0.1°C
The calculation formula is: Displayed value = measured value + (input error adjustment value/10)
Example: The measured value is 25.0°C, the input error adjustment value is 12, and the displayed
value is 26.2°C
B. Gain: Setting range: -999~1999, units: 0.001 increments