2
\$\begingroup\$

My Micro-step drive and PLC need a simple resistor network between their i/o ports.The optocouplers in the stepper drive have a max input current of 15mA, while the controller needs to output at least 20mA to give valid signals. The circuit below satisfies these requirements.

schematic

simulate this circuit – Schematic created using CircuitLab

What is a good way to mount these resistors in my PLC cabinet?

Are there terminal blocks that accommodate through hole resistors nicely, or would panel/chassis mount resistors be a better solution?

I have looked at some of the terminal blocks out there, but I haven't seen an elegant solution for adding through hole components. I have looked at panel mount resistors as well, but the power ratings are often much greater than I need.

\$\endgroup\$
4
  • \$\begingroup\$ Are you sure that the PLC MUST output 20 mA, or is it just capable of outputing 20 mA? If the latter is true, then you just need a suitable series resistor to limit input current to the optocoupler. \$\endgroup\$ Jan 20, 2019 at 16:32
  • \$\begingroup\$ Agreed. Give us a link and a page reference for the output specification. \$\endgroup\$
    – Transistor
    Jan 20, 2019 at 20:19
  • \$\begingroup\$ Check out my previous post. It is a question about the same system regarding exactly what you both are interested in. \$\endgroup\$
    – seabiscuit
    Jan 21, 2019 at 1:55
  • \$\begingroup\$ Something like this works too. digikey.com/en/products/detail/phoenix-contact/2775249/2552972 \$\endgroup\$ Feb 7, 2020 at 17:12

2 Answers 2

4
\$\begingroup\$

A search for "DIN rail component carrier" throws up images such as this.

enter image description here

Figure 1. A user-configurable PCB with screw terminals and DIN rail mount. Image source: Google image search.

For just one or two resistors or diodes it's common to connect them using standard DIN terminals.

\$\endgroup\$
2
  • \$\begingroup\$ This looks really great! \$\endgroup\$
    – seabiscuit
    Jan 20, 2019 at 16:09
  • \$\begingroup\$ I recommend that you un-accept my answer for a day or two to encourage other contributions. You'll get all sorts of ideas from them and maybe a better solution than this. Thanks. \$\endgroup\$
    – Transistor
    Jan 20, 2019 at 16:21
2
\$\begingroup\$

I know this is an old question, but I found a couple more options for this while looking for something similar:

I found this from one supplier, haven't found anyone else that makes them.

Ocean Controls 2 x 2K2 Resistor module

2 resistor module from Ocean Controls

As mentioned above, the various big terminal block manufacturers have options for soldering in components - for example, these are all from Phoenix Contact: enter image description here

Those are PTME 6-BE, UDK 4-DUR, PTTB 2,5-2BE

Phoenix also sell a solderless component holder that uses a spring clamp system to hold & connect through-hole components:

enter image description here

This replaces the blade in a disconnect terminal block - so you need 3 bits - the resistor, the component holder (P-CO), and a disconnect terminal block (e.g. ST 2,5-TG)

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.