Modbus Interfaces for Signal Boxes
Cheap, robust and easy to replace.
Introduction
For interfacing most signalbox hardware such as levers and relays to a computer simulator, we recommend using off-the-shelf industrial IO/relay interface boards. Although there may be a slightly higher upfront cost than using a hobby microcontroller board, they provide good resilience and are easy to swap with another manufacturer if there are problems in the future. Try to look for ones with socketed relays, which can then be replaced if contacts weld or coils burn out.
The openSignalBox software includes a module for Modbus IO modules, using either network or RS485. It also allows for adapters to be used to convert between the two, which is the recommended configuration. The following links are for products we have already tested with the openSignalBox software, but we also recommend for any project:
- Store Front on AliExpress
- Combined 32 channel input and output
- Combined 16 channel input 32 channel output
- Combined 16 channel input and output
- Combined 8 channel input and output
- 64 channel output
- 32 channel output
- 24 channel output
- 20 channel output
- 16 channel output
- 8 channel output
- 4 channel output
- 8 channel changeover (DPDT) output
- 64 channel input
- 32 channel input
- 16 channel input
Also we have tested this adapter for connecting many boards via a single ethernet connection:
Status
- September 2024: Ready to use.
Files
- NA
Suppliers
Photos
The following shows a very neat install at Sleaford East reproduction signalbox by Alastair Larter, using a 32 channel relay output board and a 64 channel input board:
