5.4.3Modbus Plus Port Status Indicators
The green MODBUS PLUS indicator shows the overall communication status at the BM node. Two red indicators for ERROR CHANNEL A and ERROR CHANNEL B identify errors on the two Modbus Plus cable paths.
If the ERROR CHANNEL A or ERROR CHANNEL B indicator blinks momentarily, it indicates that a message error was detected on the Modbus Plus cable path. A steady ON state indicates a hard fault exists, either in the cable or in a node device connected to it. If communication is lost on one cable path, the other path continues normally.
The MODBUS PLUS indicator flashes repetitive patterns to show the BM node's communication status on the Modbus Plus network. The patterns are:
Six Flashes per Second
This is the BM node's normal operating state. All nodes on the network should be flashing this pattern. If the indicator is OFF continuously, the BM is not transmitting on the network.
One Flash per Second
The BM node is offline after just being powered up, or after hearing a message from another node with the same network address (duplicate addresses are not allowed). In this state, the node monitors the network and builds a table of active nodes. It remains in this state for five seconds, then attempts to go to its normal operating state.
Two Flashes, then OFF for Two Seconds
The BM node is hearing the token being passed among other nodes, but is never receiving the token. Check the network link for an open or short circuit, or defective termination.
Three Flashes, then OFF for 1.7 Seconds
The BM node is not hearing any other nodes. It is claiming the token, but finding no other node to which to pass it. Check the network link for an open or short circuit, or defective termination.
Four Flashes, then OFF for 1.4 Seconds
The BM node has heard a valid message from another node that is using the same address as this node. The BM node remains offline in this state as long as it continues to hear the duplicate address. If the duplicate address is not heard for five seconds, the node then changes to the pattern of one flash every second.
31007492 | Installing the BM85 79 |