Can I Connect a Coil Relay Directly to my [c]FP-DO-4xx?
Can I connect a coil relay directly to my [c]FP-DO-400/401/403/410?
A highly inductive coil relay can cause damage to the module if reverse current overwhelms the protection built into the module. To avoid damage caused by the reverse current that might come from the coil relay, you have to insert a diode bridge for protecting your Vout terminal. This is known as a "Flyback" circuit. This inexpensive method of protecting the circuit should be employed if there is any possibility there could be reverse current. It would not negatively affect the circuit and will protect against damage. If in doubt, apply the Flyback circuit.
Flyback diodes should be used on all of the [c]FP-DO-4xx modules. The diagram below shows an example of how to connect the diodes on the 400/401 modules; more detailed information can be found in each respective module's product manual.
KnowledgeBase: 4IHG8JLE Protecting NI Switch Modules when Switching Inductive Loads
Product Manuals: FP-DO-400 and cFP-DO-400 Operating Instructions (December 2006)
Product Manuals: FP-DO-401 and cFP-DO-401 Operating Instructions (December 2006)
Product Manuals: [c]FP-DO-403 Operating Instructions and Specifications (June 2007)
Product Manuals: FP-DO-410 and cFP-DO-410 Operating Instructions (December 2006)
Report Date: 10/26/1998
Last Updated: 04/26/2016
Document ID: 1EPBH9LK