Smoke , Flame detector interfacing with PLC

Dear All,
I need to interface fire detector (Smoke, Flame , manual call point, sounder, solenoid and beacon etc) with Allen Bradley Control Logix PLC.

The detector at customer sites are Apollo make ionisation smoke detectors and Thorn make flame detector (IR type)

Problems:
These detectors when in normal state(safe state - no fire) they draw very less current (in micro amps) and in alarm state(fire) they draw something around 55milli Amps.

We need to detect fire state( = 55mA), Open circuit(0 amp or infinite resitance), short circuit(0 resistance)

How to interface smoke and flame detectors with AB CLX AI card which can read a maximum of 20mA(safe state).

Now how to design circuits(resistance etc) to use the normal AB AI card to read for open, short and fire condition.

Smoke and flame detectors give analog current.

Manual call points are digital. with manual call point we have to detect manual call point activated and open circuit (short circuit if possible as short and activation are same result)

The other issue is to find for open, short with sounders, solenoid and beacons(these are digital outputs)

The above smoke, flame, manual call points are inputs to PLC (Smoke, flame Analog input and Manual call point(digital input)

As with detecting open,short and fire condition with input signal we also have to detect for open, short circuit for solenoids, sounders and beacon. as these circuit will be off most of the time and only in case of fire it will be energised. for safety we need to monitor for open and short in solenoid or sounder or beacon and report that as a fault signal.

So each of these detectors and outputs has an End of line resistance to indicate for open circuit.

Has any one interfaced smoke,flame,beacon, sounder and solenoids.
If yes can u please tell me how to design the circuit with end of line resistance etc to get the conditioned signal to normal AI and DI card.

I thought of using AB CLX diagnostic input module and output module to detect for Open and shorts with Digital Signal. But there is no such diagnostic cards for AB Controllogix(CLX) AI card.

can you please share your experience.

Because i could not get much details from Apollo or thorn(Tyco) website.

I hope there will be some fire engineer(specialist) in this field.

thanks

I would be sure that the customer realized that their insurance carrier may go ballastic if they know this. Fire panels are rated for their use.

Oakley said:

I would be sure that the customer realized that their insurance carrier may go ballastic if they know this. Fire panels are rated for their use.

Click to expand...

Not only would they go ballistic, but I'm almost certain that the insurance would immediately become invalid without an "insurance approved" fire detection system in place.

I would have your customer double check their insurance requirements before doing any modifications.

You must use a fire panael as it has been tested and approved to detect fires and also faults as described.

But if you want your PLC to know if it is in fire mode then why not just link an auxillary contact on the fire panel to your PLC.

There are commonly available interface modules designed for what you want to do but as others have pointed out, installing a fire alarm panel would be the easiest and safest solution

not knowing why you need this detector to be connected to your PLC makes it a little hard to figure out. But. I install fire systems as part of my line of work, and yes, use a fire alarm panel. UL listed for the job, etc... Higher end panels have RS-232 ports and you can extract that info from there. What do you want to do when a device "goes in alarm"? What does the PLC operate? Is life safty invloved if the PLC should fail?

I'm interested in this topic, as I have a project too. I am working with a spray booth designer and we need to support fire detection (IE the paint spray could flash). If an alarm is detected I need to shut off the spray guns. IE no more fuel. Also all the the usual building alarms, etc.. must operate under a UL listed fire panel.