Workaround for NMT Slave to avoid blocking IO

Author: sveinse

canopen/network.py

@@ -107,8 +107,6 @@ def connect(self, *args, **kwargs) -> Network:
             for full list of supported interfaces.
         :param int bitrate:
             Bitrate in bit/s.
-        :param loop:
-            Optional, pass the loop parameter if running under asyncio
 
         :raises can.CanError:
             When connection fails.

canopen/nmt.py

@@ -286,8 +286,11 @@ def send_command(self, code: int) -> None:
         # The heartbeat service should start on the transition
         # between INITIALIZING and PRE-OPERATIONAL state
         if old_state == 0 and self._state == 127:
-            # NOTE: Blocking - OK. Protected in SdoClient
-            heartbeat_time_ms = self._local_node.sdo[0x1017].raw
+            if self._heartbeat_time_ms == 0:
+                # NOTE: Blocking - OK. Protected in SdoClient
+                heartbeat_time_ms = self._local_node.sdo[0x1017].raw
+            else:
+                heartbeat_time_ms = self._heartbeat_time_ms
             self.start_heartbeat(heartbeat_time_ms)
         else:
             self.update_heartbeat()