controls-core/src/commonMain/kotlin/space/kscience/controls/spec/DeviceSpec.kt

@@ -236,8 +236,7 @@ public fun <T, D : DeviceBase<D>> DeviceSpec<D>.logicalProperty(
 
             override val converter: MetaConverter<T> = converter
 
-            override suspend fun read(device: D): T? =
+            override suspend fun read(device: D): T? = device.getProperty(propertyName)?.let(converter::metaToObject)
-                device.getProperty(propertyName)?.let(converter::metaToObject)
 
             override suspend fun write(device: D, value: T): Unit =
                 device.writeProperty(propertyName, converter.objectToMeta(value))

demo/mks-pdr900/src/main/kotlin/center/sciprog/devices/mks/MksPdr900Device.kt

@@ -14,8 +14,12 @@ import space.kscience.dataforge.meta.get
 import space.kscience.dataforge.meta.int
 import space.kscience.dataforge.meta.transformations.MetaConverter
 
+
+//TODO this device is not tested
 class MksPdr900Device(context: Context, meta: Meta) : DeviceBySpec<MksPdr900Device>(MksPdr900Device, context, meta) {
 
+    private val address by meta.int(253)
+
     private val portDelegate = lazy {
         val ports = context.request(Ports)
         ports.buildPort(meta["port"] ?: error("Port is not defined in device configuration")).synchronous()
@@ -23,9 +27,6 @@ class MksPdr900Device(context: Context, meta: Meta) : DeviceBySpec<MksPdr900Devi
 
     private val port: SynchronousPort by portDelegate
 
-    private val address by meta.int(253)
-    private val channel by meta.int(5)
-
     private val responsePattern: Regex by lazy {
         ("@${address}ACK(.*);FF").toRegex()
     }
@@ -62,7 +63,7 @@ class MksPdr900Device(context: Context, meta: Meta) : DeviceBySpec<MksPdr900Devi
         }
     }
 
-    public suspend fun readChannelData(): Double? {
+    public suspend fun readChannelData(channel: Int): Double? {
         val answer: String? = talk("PR$channel?")
         error.invalidate()
         return if (answer.isNullOrEmpty()) {
@@ -83,12 +84,18 @@ class MksPdr900Device(context: Context, meta: Meta) : DeviceBySpec<MksPdr900Devi
 
 
     companion object : DeviceSpec<MksPdr900Device>(), Factory<MksPdr900Device> {
-        override fun build(context: Context, meta: Meta): MksPdr900Device = MksPdr900Device(context, meta)
 
+        const val DEFAULT_CHANNEL: Int = 5
+
+        override fun build(context: Context, meta: Meta): MksPdr900Device = MksPdr900Device(context, meta)
 
         val powerOn by booleanProperty(read = MksPdr900Device::readPowerOn, write = MksPdr900Device::writePowerOn)
 
-        val value by doubleProperty(read = MksPdr900Device::readChannelData)
+        val channel by logicalProperty(MetaConverter.int)
+
+        val value by doubleProperty(read = {
+            readChannelData(channel.get() ?: DEFAULT_CHANNEL)
+        })
 
         val error by logicalProperty(MetaConverter.string)
 

demo/motors/src/main/kotlin/ru/mipt/npm/devices/pimotionmaster/PiMotionMasterDevice.kt

@@ -194,9 +194,9 @@ class PiMotionMasterDevice(
         val disconnect by metaAction({
             info = "Disconnect the program from the device if it is connected"
         }) {
-            if (port != null) {
+            port?.let{
                 stop()
-                port?.close()
+                it.close()
             }
             port = null
             updateLogical(connected, false)