Quickest way to transfer descrete signals over Fiber network

[satasim0]

Guys,

I am looking for a solution to transfer Circuit Breaker status from one location to many other location in a Ring Main Scenario(as part of Load Shedding during power outage) in the quickest possible time over fiber optic network.
Can you please suggest any device which is suitable for this purpose?

Please note that PLC might not fit for this purpose as its scan time can be over 15-20ms. Solution required to get the data at the other end within few ms only.

Thank you very much.
Regards,
Matt

 

[kellian]

Ethernet io module?
Moxa make one.

 

[BryanG]

Don't know who told you that PLCs always have a scan time of 15-20ms, but it is nonsense. The scan time of the PLC depends on the speed of the PLC and the work you ask it to do. On one job I use two low end PLCs, one is very busy and despite programme optimisation has a scan time of about 30ms, the other doesn't have much to do and is regularly in the 1-2ms scan time. If you want a PLC with a fibre connection you will be looking at a high end PLC, don't ask it to do too much work and you will get very short scan times.

 

[satasim0]

Kellian, I already had chat with Moxa dealer, they have a device called IOmirror but that is going to be discontinued in a short while. Again it is not fast enough.

 

[satasim0]

Bryan, Thank you.high end PLC might do the job but I have more than 10 different location to deliver the signal and to install PLC at every location will not be very cost effective.

 

[satasim0]

Fibersystem make them. datasheet: http://www.fibersystem.se/products/fiber-optic-transfer-trip-link-3.aspx . $1800each but it only have 4 DI/DO.

 

[BobB]

What the heck - it will probably take the breakers 65ms to open anyway if they are ACBs. If you want speed Omron CompoNet can update 1000 I/O in 1ms over a 30 metre twisted pair screened cable. If there is a power outage there is no power? What do you mean - if you need to shed before generators get on line you have plenty of time. Explain your problem better - by the way, load shedding never works with generators - it is just a good idea! If two generators are loaded to say 70% each and one fails, you will never h=get the load off fast enough to save the second generator - it mat possibly stall - is that your problem?

 

[satasim0]

Hi Bob, I understand that CB's time to Open can be different but that is unchangeable so what we are trying to achieve is to get the signal delivered to CB ASAP.
We have couple of Biogas generator's running in parallel with Supply Authority. When Mains supply power is lost, Load Shed system activate and quickly open desired 22KV HV CBs to match the site load with running generator's capacity. I hope it is a bit more clear now.

Distance between CB's are in terms of 100's of meters so unfortunately Omron solution wouldn't suit. We already have Fibre link between these CBs and we prefer to use them.

 

[BobB]

Good luck - I think your biogas generators will die as you will not get the breakers open in time. This sort of load shedding does not work with diesel generators and when you consider how slow biogas or any gas generators are to react I think you are chasing your tail! I usually describe load shedding schemes wishful thinking! Sorry but I have been working with generators and automating power stations since 1992 and have not seen a load shedding system that works before the generators die. Sad to see a generator stall - have seen it quite a few times over the years when an Estop was pressed on one generator to test the so called load shedding system. If you get it to work please let me know as you will be the first to my knowledge. I have tried a few myself I can assure you. As I said - good luck!

 

[BobB]

Perhaps you should look at EtherCat - that is about as fast as anything I know of. Omron and others use it for motion control - small fast packets. http://www.ethercat.org/default.htm