StuartSelfMon

Just use a low cost dc-dc converter to step 24v down to 12v. Easier than sourcing 24v sensors.

That sounds too cheap. I thought that combination including Ethernet was nearer £200 + VAT. https://www.securitywarehouse.co.uk/catalog/intruder-alarm-c-36/security-control-panels-c-36_102/1124-input-zone-medium-c-36_102_103/honeywell-flex20-pnl-small-boxmk7-proxethernet-p-4917.html

Most modern systems - Honeywell Galaxy, Texecom, Etc. have many zones capability with double balanced circuits. This means that you can detect open and short circuits on each sensor and get a detailed message from the panel to tell you what's going on. You can use existing wiring and sensors. For existing sensors, you just add a couple of resistors to the contacts to make them double balanced. Each active sensor only requires 3 cores and passive sensors 2 cores. You can also add zone expansion using RIO's (remote I/O) for situations where you have an existing wire going to a point (existing sensor say) and you want to expand to another 8 sensors in that area. I use the Honeywell Dimension 96 (providing up to 96 detection circuits and 48 outputs) in my own home with two active 115db backlit Texecom sirens, multiple keypads, a power RIO and regular RIO. I have the E080 Ethernet module and SelfMon automation module, so have phone/smart device apps and can control the heating, garage doors, gates and lighting in combination with Home Assistant. The Dimension has a nice big reliable linear power supply - I've never seen one of those go faulty - cannot say the same for Texecom's PSU's which were plagued with issues. Disclosure - I run the SelfMon self monitoring platform.

Hi, I run SelfMon and can help you configure your system remotely. I've set up many systems this way for customers previously. All you need is a list of what you've connected and the layout. Contact me at selfmon and I'll help you out. Stuart.