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--- en:automation:02-glossary:analog-inputs-hidden [2018/09/03 13:38]
mkudlacek
+++ en:automation:02-glossary:analog-inputs-hidden [2021/06/09 08:48] (current)
avsetula
@@ Line 1: / Line 1: @@
 ====== Analog inputs ======
-Analog inputs (AI) are for reading DC voltage or DC current. The actual range is 0-10V or 0-20mA, which is an industrial standard.
+Analog inputs (AI) are for measuring analog values such as DC voltage, current and resistance. These values are produced by sensors which indicate multiple states such as thermometers, tensometers, distance meters, lux meters etc.
-The inputs are suitable for reading values from analog sensors such as temperature sensors, pressure meters, tensometers etc.
+----
+<html><span class="kbBlueText">More information about analog inputs can be found in specific categories:</span></html>\\
+<tile>
+| en:hw:007-patron:description-of-io:04-description-of-ai     | Patron             | :en:hw:unipi-kb-icon-patron.png     |
+| en:hw:01-axon:description-of-io:04-description-of-ai        | Axon               | :en:hw:unipi-kb-icon-axon.png       |
+| en:hw:02-neuron:description-of-io:04-description-of-ai      | Neuron             | :en:hw:unipi-kb-icon-neuron.png     |
+| en:hw:03-unipi11:description-of-io:04-description-of-ai     | 1.1 & 1.1 Lite     | :en:hw:unipi-kb-icon-1.png          |
+| en:hw:04-extensions:description-of-io:04-description-of-ai  | Extension modules  | :en:hw:unipi-kb-icon-extension.png  |
+</tile>
+/*
+===== Analog inputs on Neuron and Axon =====
+The functionality of AIs on Neuron and Axon is different on Group 1 and Group 2/3 and Neuron extensions.
+On Group 1, the analog input is capable of:
+  * measuring 0-10V DC
+  * measuring 0-20mA DC
 <WRAP center round tip 60%>
-On Neuron and Axon, the analog inputs can also measure resistance, making the AIs suitable for measuring temperature from resistive thermometers such as Pt100, Pt500, Pt1000 and Ni1000.
+The Group 1 is also capable of measuring the resistance, but this is achievable with [[en:automation:02-glossary:analog-outputs-hidden|Analog output]].
 </WRAP>
-===== Analog inputs on Group 1 of Neuron and Axon =====
+On Group 2 and 3 and the Neuron extensions, the analog input is capable of:
-===== Analog inputs on Group 2 and 3 of Neuron and Axon =====
+  * measuring 0-10V DC
+  * measuring 0-2.5V DC with higher precision
+  * measuring of 0-20mA DC
+  * measuring of resistance 0-100kOhm via a 2-wire method
+  * measuring of resistance 0-2kOhm via a more precise 3-wire method
+Changing between modes depends on the [[en:sw:00-start|software]] you are using, please follow the relevant tutorial.
+==== Measuring voltage ====
+==== Measuring current ====
 ===== Analog inputs on Unipi 1.1 =====
-The UniPi 1.1 has two analog inputs and they are only capable of measuring voltage in a range of 0-10V DC.
+The Unipi 1.1 has two analog inputs and they are only capable of measuring voltage in a range of 0-10V DC.
+==== Measuring resistance ====
+To measure resistance from the Unipi 1.1's AI (ie. by using PT1000 thermal probes), it is necessary to add a resistor according to the following scheme.
+{{:en:automation:02-glossary:unipi_ai.png?300|}}
+   R_sens = the sensor itself
+   R_ref = the reference resistor
+There is also a input resistor inside of the AI with the value:
+   R_ai = 12200ohm
+<WRAP center round alert 60%>
+For R_sens >= 200ohm, use R_ref = 1k. For R_sens < 200ohm, use R_ref = 10k
+</WRAP>
+The value at the AI is calculated from the voltage you read from the AI (V_ai)
+             Vcc - V_ai     R_ref * R_ai
+   R_sens = ------------ * --------------
+                V_ai        R_ref + R_ai
+The Vcc is the applied voltage (12V in the picture above).
+*/