Skip to end of metadata
Go to start of metadata

At times, a device may display as Disconnected, as in the following example.

Why is the Device Disconnected?

Certain conditions cause a PLC to be disconnected in LoopEdge.

ConditionReasons PLC Appears as DisconnectedSteps to Connect the Device

Free Tag: Explicit register name required

  • Certain device drivers, such as Allen-Bradley CompactLogix, will not have a list of register names in the DeviceHub Add Tag form.
  • When a list of registers is not provided, the case-sensitive register name must be entered exactly as it is defined in the PLC.
  • In these cases, the device will not display a Connected status until a tag with a correct register name is created.
  1. See DeviceHub Add a Tag and DeviceHub Manage Tags to add a tag with a case-sensitive register name.
HID Device in Wait State
  • Some HID (Human Interface Devices), such as barcode scanners, are always disconnected and only show a connected status when they send data to LoopEdge.
  1. This is a temporary state and no intervention is required. The device will connect when there is data to receive.
Incorrect PLC Configuration
  • If configuration changes have been made to a PLC, the best way to ensure accurate LoopEdge status is to delete and recreate the DeviceHub Device.
  1. Delete the DeviceHub Device. See DeviceHub Add, Monitor, or Delete Device.
  2. Create a new DeviceHub Device with the correct PLC configuration.
Incorrect Tag Information
  • To prevent the PLC from going into fail safe mode or from crashing the process when a tag has incorrect information, LoopEdge disconnects communication with the PLC.
  • For example, a tag may contain an incorrect address.
  1. Monitor all the tags in Flows to identify the bad tag.
  2. Find the tag with a success flag set to false.
  3. Delete the tag from DeviceHub. See DeviceHub Manage Tags.
  4. If there is no data on the flows, restart the PLC. If a node in a flow indicates "waiting for messages" and nothing is displayed in the debug console, this means that LoopEdge has stopped communicating with the PLC, so there is no data.
  • No labels