building management fault warning system?


6 posts
by bugsy_malone 666 » Tue Mar 17, 2015 10:32 am
Ok so I by trade I am an M&E engineer, I perform light maintenance around our site and work for the company who operate the site. In our buildings we have several old Sauter BMS system, which are a light greenish grey steel box install which have isolators and lights for each of the pieces of equipment to say if its running or if there is a fault.

In one building with have a persist problem with the boilers, where by through some random fault, at will the pilot light will go out causing the boiler to trip out. There are 3 boilers and in the winter you need all 3, so if one trips out 2 isnt enough to make the building warm. If you relight the pilot early employees dont notice the temperature difference, but its knowing thats happened is the problem.

So I thought what would be useful is an early warning system as we have had a few random faults which would cause less problems if acted on when the trip out light comes on rather than feeling the temperature drop or other problems. I thought this is where a Pi would fit the bill!

so I did some looking and worked out there are a total of 36 lights on the panel indicating if things are or aren't working, the lights are 6v 300ma(I think last time I replaced some they were anyway) so thought theres a powered source, but what would be the best way to monitor all these points? I figured maybe a bank of relays, but that seems like a rather large solution, so wondered what sort of thing could be built to make it any smaller?

The idea then is that the Pi would then send a text message some how to me, so I know first thing in the morning or before hand to go and look at the equipment and get it running to create seamless running to the rest of the staff. Potentially if there is WiFi range I could get it to email me so when I sit down first thing in the morning I'd know what the problem was and then go fix it, but a text seems better (I know its also possible to send SMS through the web so could be done that way)

So I have ideas on how it could be done, but I am looking at the fact there are not enough GPIO pins and I am still a noob when it comes to doing this sort of stuff as I havent had acres of time to understand its workings, I'm open to suggestions and any help would be greatly appreciated for this project.
User avatar
Posts: 268
Joined: Mon Dec 17, 2012 10:50 pm
Location: Basingstoke UK
by BMS Doug » Tue Mar 17, 2015 11:33 am
bugsy_malone 666 wrote:Ok so I by trade I am an M&E engineer, I perform light maintenance around our site and work for the company who operate the site. In our buildings we have several old Sauter BMS system, which are a light greenish grey steel box install which have isolators and lights for each of the pieces of equipment to say if its running or if there is a fault.

In one building with have a persist problem with the boilers, where by through some random fault, at will the pilot light will go out causing the boiler to trip out. There are 3 boilers and in the winter you need all 3, so if one trips out 2 isnt enough to make the building warm. If you relight the pilot early employees dont notice the temperature difference, but its knowing thats happened is the problem.

So I thought what would be useful is an early warning system as we have had a few random faults which would cause less problems if acted on when the trip out light comes on rather than feeling the temperature drop or other problems. I thought this is where a Pi would fit the bill!

so I did some looking and worked out there are a total of 36 lights on the panel indicating if things are or aren't working, the lights are 6v 300ma(I think last time I replaced some they were anyway) so thought theres a powered source, but what would be the best way to monitor all these points? I figured maybe a bank of relays, but that seems like a rather large solution, so wondered what sort of thing could be built to make it any smaller?

The idea then is that the Pi would then send a text message some how to me, so I know first thing in the morning or before hand to go and look at the equipment and get it running to create seamless running to the rest of the staff. Potentially if there is WiFi range I could get it to email me so when I sit down first thing in the morning I'd know what the problem was and then go fix it, but a text seems better (I know its also possible to send SMS through the web so could be done that way)

So I have ideas on how it could be done, but I am looking at the fact there are not enough GPIO pins and I am still a noob when it comes to doing this sort of stuff as I havent had acres of time to understand its workings, I'm open to suggestions and any help would be greatly appreciated for this project.


the simplest fashion might be to point a Pi camera at the fault lights and use a visual check (you can also program in a recognition program that will identify the state of each light).

If that isn't practical (plantroom may not be a safe place to leave a pi-cam lying around) you may find that the relays already exist (general all of the lights are energised by relays, these often have a spare set of terminals available which you could use for your pi). you can use i2c I/O expanders to increase the amount of inputs you have available.
Doug.
Building Management Systems Engineer.
Posts: 3774
Joined: Thu Mar 27, 2014 2:42 pm
Location: London, UK
by bugsy_malone 666 » Tue Mar 17, 2015 12:53 pm
Yes the Camera Idea did indeed cross my mind, as I have read about using that sort of picture change technology as a PIR also. I think the problem I found was bits of plant were in the way so you wouldnt see enough of the panel.

I'll have to have a chat with our plant engineer while he's on site today to see if there is a relay bank, as it would save alot of extra wire!
User avatar
Posts: 268
Joined: Mon Dec 17, 2012 10:50 pm
Location: Basingstoke UK
by stevend » Tue Mar 17, 2015 1:44 pm
Rather than relays, you could just wire an optocoupler with a series resistor across each bulb. This would only add a few mA of current drain to each lamp driver circuit - so very unlikely to be a problem.

Then read in all the opto outputs via some interface - maybe an I2C-based module.

It may be that the lamps are driven with a.c. instead of d.c. Not a problem - I just added a capacitor across the output of the opto to hold the output low until the next pulse came along. I also used a.c. input optos.

You might need some schmitt trigger buffers on the opto outputs anyway, to make the circuit less prone to noise. Or you can filter in software.
Posts: 125
Joined: Fri Oct 11, 2013 12:28 pm
by bugsy_malone 666 » Tue Mar 17, 2015 4:25 pm
Ok so just finished chatting with our engineer and it turns out that we have 2 different but essentially the same systems.

The system where we have more issues run on 'tranilamps', I had to laugh at the name but basically 240v input and a transformer in the lamp holder to bring it down to the 6v of the lamp. With the I figured you could actually use an induction clamp on each of the lamps supply cables would probably work in a non interfering way.

The other building, all the lamps are 24v apparently, although part of me thinks they are 6v lamps as well, I'll have to check that.
User avatar
Posts: 268
Joined: Mon Dec 17, 2012 10:50 pm
Location: Basingstoke UK
by stevend » Tue Mar 17, 2015 8:02 pm
bugsy_malone 666 wrote:The system where we have more issues run on 'tranilamps', I had to laugh at the name but basically 240v input and a transformer in the lamp holder to bring it down to the 6v of the lamp. With the I figured you could actually use an induction clamp on each of the lamps supply cables would probably work in a non interfering way.

I doubt the tranilamps will consume enough current to reliably trigger an induction-clamp type detector - if I've got the style of lamp right, they probably only take a watt or two each, which is a negligible current at 240V.
Given the location, I'd suggest some of the 'professional' isolating opto modules, which are available with 240V input and opto output - such as http://uk.rs-online.com/web/p/optocouplers/7730017/, or uints made by Opto 22 and similar. Just wire across the mains input to the lamp.

Alternatively, this post has a 'do it yourself' method, if you're able to address the safety aspects of a work location.

Or maybe there's a tranilamp replacement with a tellback contact.
Posts: 125
Joined: Fri Oct 11, 2013 12:28 pm