diff --git a/code/components/jomjol_flowcontroll/ClassFlowDefineTypes.h b/code/components/jomjol_flowcontroll/ClassFlowDefineTypes.h
index 059a55b8f..a9750bc3f 100644
--- a/code/components/jomjol_flowcontroll/ClassFlowDefineTypes.h
+++ b/code/components/jomjol_flowcontroll/ClassFlowDefineTypes.h
@@ -5,6 +5,10 @@
 
 #include "ClassFlowImage.h"
 
+/**
+ * Properties of one ROI
+ * FIXME: naming of members could use some refactoring to comply with common C++ coding style guidelines
+ */
 struct roi {
     int posx, posy, deltax, deltay;
     float result_float;
@@ -14,56 +18,64 @@ struct roi {
     CImageBasis *image, *image_org;
 };
 
+/**
+ * FIXME: Why is this additional layer needed?
+ */
 struct general {
     string name;
     std::vector<roi*> ROI;
 };
 
 enum t_RateType {
-    AbsoluteChange,
-    RateChange
+    AbsoluteChange, // ignores the time difference; only the value difference is used comparison with NumberPost.maxRate
+    RateChange      // time difference is considered and a normalized rate is used for comparison with NumberPost.maxRate
  };
 
 
+/**
+ * Holds all properties and settings of a sequence. A sequence is a set of digital and/or analog ROIs that are combined to 
+ * provide one meter reading (value).
+ * FIXME: can be renamed to `Sequence`
+ */
 struct NumberPost {
-    float MaxRateValue;
-    bool useMaxRateValue;
-    t_RateType RateType;
-    bool ErrorMessage;
-    bool PreValueOkay;
-    bool AllowNegativeRates;
-    bool checkDigitIncreaseConsistency;
-    time_t lastvalue;
-    time_t timeStampTimeUTC;
-    string timeStamp;
-    double FlowRateAct; // m3 / min
-    double PreValue; // last value that was read out well
-    double Value; // last value read out, incl. corrections
-    string ReturnRateValue; // return value rate
-    string ReturnChangeAbsolute; // return value rate
-    string ReturnRawValue; // Raw value (with N & leading 0)    
-    string ReturnValue; // corrected return value, if necessary with error message
-    string ReturnPreValue; // corrected return value without error message
-    string ErrorMessageText; // Error message for consistency check
-    int AnzahlAnalog;
-    int AnzahlDigital;
-    int DecimalShift;
-    int DecimalShiftInitial;
-    float AnalogDigitalTransitionStart; // When is the digit > x.1, i.e. when does it start to tilt?
-    int Nachkomma;
+    float MaxRateValue;         // maxRate; upper bound for the difference between two consecutive readings; affected by maxRateType;
+    bool useMaxRateValue;       // consistencyChecksEnabled; enables consistency checks; uses maxRate and maxRateType
+    t_RateType RateType;        // maxRateType; affects how the value of maxRate is used for comparing the current and previous value
+    bool ErrorMessage;          // FIXME: not used; can be removed
+    bool PreValueOkay;          // previousValueValid; indicates that the reading of the previous round has no errors
+    bool AllowNegativeRates;    // allowNegativeRate; defines if the consistency checks allow negative rates between consecutive meter readings.
+    bool checkDigitIncreaseConsistency; // extendedConsistencyCheck; performs an additional consistency check to avoid wrong readings
+    time_t lastvalue;           // previousValueTimestamp; FIXME: usage in the code is ambigious, as sometimes it's `time_t` and sometimes `struct tm`
+    time_t timeStampTimeUTC;    // FIXME: not used; can be removed.
+    string timeStamp;           // localTimeStr; timestamp of last valid reading formatted as local time
+    double FlowRateAct;         // currentRate; ΔValue/min; since usage is not limited to water meters, the physical unit is not known.
+    double PreValue;            // lastValidValue; most recent value that could be read w/o any errors
+    double Value;               // value; most recent readout; may include corrections
+    string ReturnRateValue;     // currentRateStr; current normalized rate; ΔValue/min
+    string ReturnChangeAbsolute; // currentChangeStr; absolute difference between current and previous measurement
+    string ReturnRawValue;      // rawValueStr; Raw value (with N & leading 0)    
+    string ReturnValue;         // valueStr; corrected return value, if necessary with error message
+    string ReturnPreValue;      // lastValidValueStr; corrected return value without error message
+    string ErrorMessageText;    // errorMessage; Error message for consistency checks
+    int AnzahlAnalog;           // numAnalogRoi; number of analog ROIs used in this sequence
+    int AnzahlDigital;          // numDigitalRoi; number of digital ROIs used in this sequence
+    int DecimalShift;           // decimalShift; each increment shifts the decimal separator by one digit; value=value*10^decimalShift; pos. value shifts to the right
+    int DecimalShiftInitial;    // decimalShiftInitial; same as decimalShift but is a const to reset decimalShift after calculations
+    float AnalogDigitalTransitionStart; // analogDigitalTransitionStartValue; FIXME: need a better description; When is the digit > x.1, i.e. when does it start to tilt?
+    int Nachkomma;              // decimalPlaces; usually defined by the number of analog ROIs; affected by DecimalShift
 
-    string FieldV1; // Fieldname in InfluxDBv1  
-    string MeasurementV1;   // Measurement in InfluxDBv1
+    string FieldV1;             // influxdbFieldName_v1; Name of the Field in InfluxDBv1
+    string MeasurementV1;       // influxdbMeasurementName_v1; Name of the Measurement in InfluxDBv1
 
-    string FieldV2;         // Fieldname in InfluxDBv2  
-    string MeasurementV2;   // Measurement in InfluxDBv2
+    string FieldV2;             // influxdbFieldName_v2; Name of the Field in InfluxDBv2
+    string MeasurementV2;       // influxdbMeasurementName_v2; Name of the Measurement in InfluxDBv2
 
-    bool isExtendedResolution;
+    bool isExtendedResolution;  // extendResolution; Adds the decimal place of the least significant analog ROI to the value
 
-    general *digit_roi;
-    general *analog_roi;
+    general *digit_roi;         // digitalRoi; set of digital ROIs for the sequence
+    general *analog_roi;        // analogRoi; set of analog ROIs for the sequence
 
-    string name;
+    string name;                // name; Designation for the sequence 
 };
 
 #endif