I'm designing a controller with an op amp output (at a nominal 0 to 10v DC) that will be connected off the circuit board to a dimmer. This will be installed in a mains voltage DIN rail cabinet (230V AC environment).

Do I need to add a TVS diode to the output to protect against transients ? Something a bit like PESDxL1BA ?

I think I'm kind of answering my own questions even as I type, but some confirmation would be handy.

 

If the dimmer is the type designed to be controlled by a zero to ten volt signal, and if the connection will be of a permanent nature, not subject to random disconnection, then there is no need for a separate TVS protection device.
Otherwise, a simple pair of clamp diodes to prevent the opamp output from receiving a voltage above the opamp V+ or below it's V-, along with a 100 ohm series resistor, is all that you need.

 

If the dimmer is the type designed to be controlled by a zero to ten volt signal, and if the connection will be of a permanent nature, not subject to random disconnection, then there is no need for a separate TVS protection device.
Otherwise, a simple pair of clamp diodes to prevent the opamp output from receiving a voltage above the opamp V+ or below it's V-, along with a 100 ohm series resistor, is all that you need.

Yes, the connection will be permanent once installed. I'll take a look at using steering diodes as suggested

 

Yes, the connection will be permanent once installed. I'll take a look at using steering diodes as suggested

Here's the portion of the circuit, as modified.


The power rail is 24V DC so this will clip it to one diode drop lower.

 

Here's the portion of the circuit, as modified.
View attachment 290187

The power rail is 24V DC so this will clip it to one diode drop lower.

In this application they are clamping diodes, as they clamp the voltage to within limits. ( I know this is being picky.)