Using DHCP

DHCP makes it easy to configure and test the FieldPoint system in different applications. Static IP assignment requires more user involvement in initial configuration but is more reliable.

If a FieldPoint network module is configured to use DHCP and cannot connect to the DHCP server on startup, the network module pauses for up to a few minutes while it tries to connect to the DHCP server. If the FieldPoint system can become disconnected from the network, assign a static IP address to the network module.

Depending on whether Halt if TCP/IP Fails is checked, expect the following behavior from LabVIEW RT 7.0 or later and a LabVIEW RT controller on DHCP failure or on any other TCP/IP failure:

Halt if TCP/IP Fails is checked: If TCP/IP fails for any reason on system startup, LabVIEW RT restarts the controller and attempts to connect again. After three failed attempts, LabVIEW RT resets the controller to IP address 0.0.0.0.

Halt if TCP/IP Fails is unchecked: LabVIEW RT starts and runs applications on the controller at system startup, even if TCP/IP fails. When the connection becomes available, you must manually restart the controller in order to connect it to the network.

Depending on whether Halt if TCP/IP Fails is checked, expect the following behavior from a cFP-180x on DHCP failure or on any other TCP/IP failure:

Halt if TCP/IP Fails is checked: If TCP/IP fails for any reason on system startup, the network module restarts and attempts to connect again. After three failed attempts, the network module resets its IP address to 0.0.0.0 and boots into safe mode.

Halt if TCP/IP Fails is unchecked: The network module starts the OptoMUX server on the RS-232 port even if TCP/IP fails. When the connection becomes available, you must manually restart the controller in order to connect it to the Ethernet network.