diff --git a/src/php/AdminApps/DerivedSignals.php b/src/php/AdminApps/DerivedSignals.php
index 7d3fe5b..664395a 100644
--- a/src/php/AdminApps/DerivedSignals.php
+++ b/src/php/AdminApps/DerivedSignals.php
@@ -21,8 +21,43 @@ class DerivedSignals implements \SourcePot\Datapool\Interfaces\App{
         'Y-m-d'=>'Y-m-d 12:30:00',
         'Y-m'=>'Y-m-15 12:30:00',
         'Y'=>'Y-06-15 12:30:00',
-    ];    
+    ];
+
+    private const TIMESPAN_OPTIONS=[
+        'Y-m-d H:i'=>'Minute',
+        'Y-m-d H'=>'Hour',
+        'Y-m-d'=>'Day',
+        'Y-m'=>'Month',
+        'Y'=>'Year',
+    ];
     
+    private const PROCESSING_OPTIONS=[
+        'avg'=>'Average',
+        'min'=>'Min',
+        'minExZero'=>'Min exclude zero',
+        'max'=>'Max',
+        'range'=>'Range',
+        'sum'=>'Sum',
+        'count'=>'Count',
+    ];
+
+    private const CONTENTSTRUCTURE_PARAMS=[
+        'Timespan'=>['method'=>'select','excontainer'=>TRUE,'value'=>'','options'=>self::TIMESPAN_OPTIONS,'keep-element-content'=>TRUE,'excontainer'=>TRUE],
+        'Timezone'=>['method'=>'select','excontainer'=>TRUE,'value'=>'','options'=>\SourcePot\Datapool\Root::TIMEZONES,'value'=>\SourcePot\Datapool\Root::DB_TIMEZONE,'keep-element-content'=>TRUE,'excontainer'=>TRUE],
+        'yMin'=>['method'=>'element','tag'=>'input','type'=>'text','excontainer'=>TRUE],
+        'yMax'=>['method'=>'element','tag'=>'input','type'=>'text','excontainer'=>TRUE],
+        'Data type'=>['method'=>'select','excontainer'=>TRUE,'value'=>'float','options'=>\SourcePot\Datapool\Foundation\Computations::DATA_TYPES,'keep-element-content'=>TRUE],
+        'description'=>['method'=>'element','tag'=>'input','type'=>'text','excontainer'=>TRUE],
+    ];
+		
+    private const CONTENTSTRUCTURE_RULES=[
+        'Operation'=>['method'=>'select','excontainer'=>TRUE,'value'=>'+','options'=>['+'=>'+','-'=>'-','*'=>'*'],'keep-element-content'=>TRUE,'excontainer'=>TRUE],
+        'Signal'=>['method'=>'select','excontainer'=>TRUE,'value'=>'','options'=>[],'keep-element-content'=>TRUE,'excontainer'=>TRUE],
+        'Processing'=>['method'=>'select','excontainer'=>TRUE,'value'=>'','options'=>self::PROCESSING_OPTIONS,'keep-element-content'=>TRUE,'excontainer'=>TRUE],
+        'Offset'=>['method'=>'element','tag'=>'input','type'=>'text','value'=>0,'excontainer'=>TRUE],
+        'Scaler'=>['method'=>'element','tag'=>'input','type'=>'text','value'=>1,'excontainer'=>TRUE],
+    ];	
+
     private $entryTable='';
     private $entryTemplate=[
         'Expires'=>['type'=>'DATETIME','value'=>\SourcePot\Datapool\Root::NULL_DATE,'Description'=>'If the current date is later than the Expires-date the entry will be deleted. On insert-entry the init-value is used only if the Owner is not anonymous, set to 10mins otherwise.'],
@@ -94,23 +129,7 @@ private function signalsDerived(array $selector):string
 
     public function derivedSignalParams($arr):array
     {
-    // rules
-        $timespanOptions=[
-            'Y-m-d H:i'=>'Minute',
-            'Y-m-d H'=>'Hour',
-            'Y-m-d'=>'Day',
-            'Y-m'=>'Month',
-            'Y'=>'Year',
-        ];
-        $contentStructure=[
-            'Timespan'=>['method'=>'select','excontainer'=>TRUE,'value'=>'','options'=>$timespanOptions,'keep-element-content'=>TRUE,'excontainer'=>TRUE],
-            'Timezone'=>['method'=>'select','excontainer'=>TRUE,'value'=>'','options'=>\SourcePot\Datapool\Root::TIMEZONES,'value'=>\SourcePot\Datapool\Root::DB_TIMEZONE,'keep-element-content'=>TRUE,'excontainer'=>TRUE],
-            'min'=>['method'=>'element','tag'=>'input','type'=>'text','excontainer'=>TRUE],
-            'max'=>['method'=>'element','tag'=>'input','type'=>'text','excontainer'=>TRUE],
-            'description'=>['method'=>'element','tag'=>'input','type'=>'text','excontainer'=>TRUE],
-        ];
-		// rules list
-        $arr['contentStructure']=$contentStructure;
+        $arr['contentStructure']=self::CONTENTSTRUCTURE_PARAMS;
 		$caption='Params for '.$arr['selector']['Group'].' → '.$arr['selector']['Folder'];
         $row=$this->oc['SourcePot\Datapool\Tools\HTMLbuilder']->entry2row($arr);
         $arr['html']=$this->oc['SourcePot\Datapool\Tools\HTMLbuilder']->table(['matrix'=>['Parameter'=>$row],'style'=>'clear:left;','hideHeader'=>FALSE,'hideKeys'=>TRUE,'keep-element-content'=>TRUE,'caption'=>$caption]);
@@ -119,33 +138,14 @@ public function derivedSignalParams($arr):array
     
     public function derivedSignalRules($arr):array
     {
-		// rules
-        $signalOptions=$this->oc['SourcePot\Datapool\Foundation\Signals']->getOptions(['Group'=>'signal']);
-        $processingOptions=[
-            'avg'=>'Average',
-            'min'=>'Min',
-            'minExZero'=>'Min exclude zero',
-            'max'=>'Max',
-            'range'=>'Range',
-            'sum'=>'Sum',
-            'count'=>'Count',
-        ];
-        $contentStructure=[
-            'Operation'=>['method'=>'select','excontainer'=>TRUE,'value'=>'+','options'=>['+'=>'+','-'=>'-','*'=>'*'],'keep-element-content'=>TRUE,'excontainer'=>TRUE],
-            'Signal'=>['method'=>'select','excontainer'=>TRUE,'value'=>'','options'=>$signalOptions,'keep-element-content'=>TRUE,'excontainer'=>TRUE],
-            'Processing'=>['method'=>'select','excontainer'=>TRUE,'value'=>'','options'=>$processingOptions,'keep-element-content'=>TRUE,'excontainer'=>TRUE],
-            'Offset'=>['method'=>'element','tag'=>'input','type'=>'text','value'=>0,'excontainer'=>TRUE],
-            'Scaler'=>['method'=>'element','tag'=>'input','type'=>'text','value'=>1,'excontainer'=>TRUE],
-        ];
-		// rules list
+		$contentStructure=self::CONTENTSTRUCTURE_RULES;
+        $contentStructure['Signal']['options']=$this->oc['SourcePot\Datapool\Foundation\Signals']->getOptions(['Group'=>'signal']);
         $arr['contentStructure']=$contentStructure;
 		$arr['caption']='Rules for '.$arr['selector']['Group'].' → '.$arr['selector']['Folder'];
 		$arr['html']=$this->oc['SourcePot\Datapool\Tools\HTMLbuilder']->entryListEditor($arr);
 		return $arr;
 	}
 
-
-
     public function signal2derivedSignal(array $signal):void
     {
         // get relevant derived signals
@@ -187,16 +187,15 @@ public function signal2derivedSignal(array $signal):void
                 }
             }
             // signal params
-            $signalParams=['description'=>$params['description']];
-            $signalParams['yMin']=$params['min']??NULL;
-            $signalParams['yMax']=$params['max']??NULL;
+            $params['yMin']=(empty(strval($params['yMin'])))?NULL:$params['yMin'];
+            $params['yMax']=(empty(strval($params['yMax'])))?NULL:$params['yMax'];
             $targetTimeZone=new \DateTimeZone($params['Timezone']);
             $nowDateTime=new \DateTime('@'.time());
             $nowDateTime->setTimezone($targetTimeZone);
             $dateTimeStr=$nowDateTime->format(self::BASE_DATETIME[$params['Timespan']]);
             $signalDateTime=new \DateTime($dateTimeStr,new \DateTimeZone($params['Timezone']));
             $signalTimeStamp=$signalDateTime->getTimestamp();
-            $this->oc['SourcePot\Datapool\Foundation\Signals']->updateSignal(__CLASS__,$params['Group'],$params['Folder'],$result,'float',$signalParams,$signalTimeStamp);
+            $this->oc['SourcePot\Datapool\Foundation\Signals']->updateSignal(__CLASS__,$params['Group'],$params['Folder'],$result,$params['Data type']??'float',$params,$signalTimeStamp);
         }
     }
 
diff --git a/src/php/Foundation/Access.php b/src/php/Foundation/Access.php
index 7d446b2..73c909d 100644
--- a/src/php/Foundation/Access.php
+++ b/src/php/Foundation/Access.php
@@ -154,15 +154,19 @@ public function emailId($email){
         return $emailId;
     }
 
-    public function loginId($email,$password){
+    public function loginId($email,$password):string
+    {
         $emailId=$this->emailId($email);
         $userPass=$password.$emailId;
         $loginId=password_hash($userPass,PASSWORD_DEFAULT);
         return $loginId;
     }
     
-    public function verfiyPassword($email,$password,$loginId){
-        if (empty($email) || empty($password) || empty($loginId)){return FALSE;}
+    public function verfiyPassword($email,$password,$loginId):bool
+    {
+        if (empty($email) || empty($password) || empty($loginId)){
+            return FALSE;
+        }
         $emailId=$this->emailId($email);
         $userPass=$password.$emailId;
         if (password_verify($userPass,$loginId)===TRUE){
@@ -173,7 +177,8 @@ public function verfiyPassword($email,$password,$loginId){
         }
     }
     
-    private function rehashPswIfNeeded($user,$userPass,$loginId){
+    private function rehashPswIfNeeded($user,$userPass,$loginId):bool
+    {
         if (password_needs_rehash($loginId,PASSWORD_DEFAULT)){
             $user['LoginId']=password_hash($userPass,PASSWORD_DEFAULT);
             $this->oc['SourcePot\Datapool\Foundation\Database']->updateEntry($user,TRUE);
@@ -184,31 +189,38 @@ private function rehashPswIfNeeded($user,$userPass,$loginId){
         }
     }
 
-    public function isAdmin($user=FALSE){
+    public function isAdmin($user=FALSE):bool
+    {
         return $this->hasRights($user,'ADMIN_R');
     }
     
-    public function isContentAdmin($user=FALSE){
+    public function isContentAdmin($user=FALSE):bool
+    {
         return $this->hasRights($user,'ALL_CONTENTADMIN_R');
     }
     
-    public function isMember($user=FALSE){
+    public function isMember($user=FALSE):bool
+    {
         return $this->hasRights($user,'ALL_MEMBER_R');
     }
     
-    public function isPublic($user=FALSE){
+    public function isPublic($user=FALSE):bool
+    {
         return $this->hasRights($user,'PUBLIC_R');
     }
     
-    public function isRegistered($user=FALSE){
+    public function isRegistered($user=FALSE):bool
+    {
         return $this->hasRights($user,'REGISTERED_R');
     }
     
-    public function hasRights($user=FALSE,string $right='ADMIN_R')
+    public function hasRights($user=FALSE,string $right='ADMIN_R'):bool
     {
         if (empty($user)){
             $user=$this->oc['SourcePot\Datapool\Root']->getCurrentUser();
-            if (empty($user)){return FALSE;}
+            if (empty($user)){
+                return FALSE;
+            }
         }
         if (($user['Privileges'] & $this->access[$right])>0){
             return TRUE;
@@ -217,11 +229,13 @@ public function hasRights($user=FALSE,string $right='ADMIN_R')
         }    
     }
 
-    public function hasAccess($user=FALSE,int $right=32768)
+    public function hasAccess($user=FALSE,int $right=32768):bool
     {
         if (empty($user)){
             $user=$this->oc['SourcePot\Datapool\Root']->getCurrentUser();
-            if (empty($user)){return FALSE;}
+            if (empty($user)){
+                return FALSE;
+            }
         }
         if (($user['Privileges'] & $right)>0){
             return TRUE;
diff --git a/src/php/Foundation/Filespace.php b/src/php/Foundation/Filespace.php
index a141c73..22e13e0 100644
--- a/src/php/Foundation/Filespace.php
+++ b/src/php/Foundation/Filespace.php
@@ -714,13 +714,18 @@ public function addFile2entry(array $entry,string $file):array
                 $this->oc['logger']->log('notice','Function "{class} → {function}()" failed to scan for pdf-attachments: {msg}',$context);
             }    
         } else if (stripos(strval($entry['Params']['File']['Extension']),'csv')!==FALSE){
-                $entry['Params']['File']['Spreadsheet']=$this->oc['SourcePot\Datapool\Tools\CSVtools']->csvIterator($file,$entry['Params']['File']['Extension'])->current();
-                $entry['Params']['File']['SpreadsheetIteratorClass']='SourcePot\Datapool\Tools\CSVtools';
-                $entry['Params']['File']['SpreadsheetIteratorMethod']='csvIterator';
+            $entry['Params']['File']['Spreadsheet']=$this->oc['SourcePot\Datapool\Tools\CSVtools']->csvIterator($file,$entry['Params']['File']['Extension'])->current();
+            $entry['Params']['File']['SpreadsheetIteratorClass']='SourcePot\Datapool\Tools\CSVtools';
+            $entry['Params']['File']['SpreadsheetIteratorMethod']='csvIterator';
         } else if (stripos(strval($entry['Params']['File']['Extension']),'xls')!==FALSE){
-                $entry['Params']['File']['Spreadsheet']=$this->oc['SourcePot\Datapool\Tools\XLStools']->iterator($file,$entry['Params']['File']['Extension'])->current();
-                $entry['Params']['File']['SpreadsheetIteratorClass']='SourcePot\Datapool\Tools\XLStools';
-                $entry['Params']['File']['SpreadsheetIteratorMethod']='iterator';
+            $entry['Params']['File']['Spreadsheet']=$this->oc['SourcePot\Datapool\Tools\XLStools']->iterator($file,$entry['Params']['File']['Extension'])->current();
+            $entry['Params']['File']['SpreadsheetIteratorClass']='SourcePot\Datapool\Tools\XLStools';
+            $entry['Params']['File']['SpreadsheetIteratorMethod']='iterator';
+        } else if (stripos(strval($entry['Params']['File']['Extension']),'txt')!==FALSE){
+            $entry['Content']['File content']=file_get_contents($file);
+        } else if (stripos(strval($entry['Params']['File']['Extension']),'json')!==FALSE){
+            $fileContent=file_get_contents($file)?:'{}';
+            $entry['Content']=$this->oc['SourcePot\Datapool\Tools\MiscTools']->json2arr($fileContent);
         }
         // add file to entry
         if (empty($entry['EntryId'])){
diff --git a/src/php/Root.php b/src/php/Root.php
index 5e81827..7ab3cb4 100644
--- a/src/php/Root.php
+++ b/src/php/Root.php
@@ -397,7 +397,7 @@ public function run():array
             // job Processing
             $loadAvg=$this->getLoadAvg();
             $loadAvgThreshold=self::JOB_AVERAGE_LOAD_THRESHOLD_MULTIPLIER*$loadAvg['avg'];
-            if ($loadAvg['Load [%]']<$loadAvgThreshold){
+            if ($loadAvg['Load [%]']<$loadAvgThreshold || $loadAvg['Load [%]']===0){
                 $arr=$this->oc['SourcePot\Datapool\Foundation\Job']->trigger($arr);
             } else {
                 $arr['page html']='Job skipped due to high server load (threshold='.round($loadAvgThreshold).')...';
@@ -827,13 +827,15 @@ public function getLoadAvg():array
     {
         $loadAvg=['OS'=>PHP_OS,'Load'=>0];
         if (stripos(PHP_OS,'linux')!==FALSE){
+            // Linux OS
             if (function_exists('sys_getloadavg')){
                 $loadAvg['Load']=sys_getloadavg()[0];
             } else {
                 $data=file_get_contents('/proc/loadavg');
-                $loadAvg['Load']=explode(' ', $data)[0];
+                $loadAvg['Load']=explode(' ',$data?:0)[0];
             }
         } else if (stripos(PHP_OS,'win')!==FALSE){
+            // Windows OS
             exec("wmic cpu get loadpercentage /all",$execReturn);
             foreach($execReturn as $line) {
                 if (is_numeric(trim($line))){
@@ -841,6 +843,14 @@ public function getLoadAvg():array
                     break;
                 }
             }
+        } else {
+            // other OS (e.g. MacOS)
+            if (function_exists('sys_getloadavg')){
+                $loadAvg['Load']=sys_getloadavg()[0];
+            } else {
+                $data=file_get_contents('/proc/loadavg');
+                $loadAvg['Load']=explode(' ',$data?:0)[0];
+            }
         }
         $loadAvg['Load [%]']=round($loadAvg['Load']*100);
         // add measurements to signal