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--- eeros_architecture:hal:scaling [2017/05/11 12:13] – [Configuring an Encoder Input] graf
+++ eeros_architecture:hal:scaling [2022/05/06 21:09] (current) – jonasfrei
@@ Line 1: / Line 1: @@
 ====== Scale and Range of Analog Signals ======
-Within eeros we work with signals having physically meaningful units. However, when such signals are read from real-world hardware we use analog-to-digital converters or encoder which are basically counters. When outputting such signals we use digital-to-analog converters. These counters or converters all deliver or need an integer value. Its maximum and minimum value depend on the resolution of the underlying hardware. The ''scale'' and ''range'' key allows to convert between the necessary integer value and the physically meaningsful signals.
+Within EEROS we work with signals having physically meaningful units. However, when such signals are read from real-world hardware we use analog-to-digital converters or encoder which are basically counters. When outputting such signals we use digital-to-analog converters. These counters or converters all deliver or need an integer value. Its maximum and minimum value depend on the resolution of the underlying hardware. The ''scale'' and ''range'' key allows to convert between the necessary integer value and the physically meaningful signals. You might have several stages in your hardware, see [[eeros_architecture:hal:scaling_multi|]].
 ===== Configuring an Analog Output =====
@@ Line 9: / Line 9: @@
   - Enter this limits in the configuration file under ''range'' with ''minIn'' and ''maxIn''.
   - Write a small digital value to the analog output directly (not through eeros). That is, if your are using comedi for instance, you use a user interface and write a value of 1000 to one of its analog outputs.
-  - Record this digital value it in the configuration file under ''scale'' as ''minIn''
+  - Record this digital value in the configuration file under ''scale'' as ''minIn''
   - Measure the resulting voltage with a multimeter and record it in the configuration file under ''scale'' as ''minOut''.
   - Repeat this with a large digital value close to the upper limit. For this you have to know the range of your digital-to-analog converter.
-  - Record this digital value it in the configuration file under ''scale'' as ''maxIn''
+  - Record this digital value in the configuration file under ''scale'' as ''maxIn''
   - Measure the resulting voltage with a multimeter and record it in the configuration file under ''scale'' ''maxOut''.
@@ Line 28: / Line 28: @@
   }
 </code>
+If you know the scale and offset of your channel you could give these values directly as:
+<code>
+  "channel0": {
+    "signalId": "dacOut0",
+    "scale": [ { "id" : "dac",
+                 "scale":  0.5,
+                 "offset": 2.5 } ],
+    "range": [ { "id" : "dac",
+                 "minIn":       0, "maxIn":  65536,
+                 "minOut":  -10.0, "maxOut":  10.0 } ],
+    "unit": "V"
+  }
+</code>
 ===== Configuring an Analog Input =====