Remote station control

I have the need to control 4 remote stations from a central location. Remote stations are 6 miles from central. Remote stations have DL05 processors, centeral station will have Compact logix. Only existing lines are telephone, no internet at remote stations. Use of radio type devices (cell or anything with antenna) will not be allowed.

The remote stations will have a comms heartbeat, and get start/stop and 1 real number from central. Will need to tell central status of running and 2 real numbers.

Any ideas on how to accomplish this?

jeremy_campbell said:

I have the need to control 4 remote stations from a central location. Remote stations are 6 miles from central. Remote stations have DL05 processors, centeral station will have Compact logix. Only existing lines are telephone, no internet at remote stations. Use of radio type devices (cell or anything with antenna) will not be allowed.

The remote stations will have a comms heartbeat, and get start/stop and 1 real number from central. Will need to tell central status of running and 2 real numbers.

Any ideas on how to accomplish this?

Click to expand...

You could use phone modems to communicate, but you could possibly also add DSL modems on both sides. Depending on reliability, or how often you need to communicate, a protocol like DNP3 might be helpful to buffer data.

Satellite comm is an option.

But not to allow radio...that's ridiculous. What's the reasoning behind that if you can say?

I would look at dry leased line loops and use whatever protocol your hardware supports over serial over the modems over the dedicated lines. dry loops run about $1000 a month in British Columbia the last time I got a quote, although that was for a 50-60 km run.

dry leased loop would be the most reliable and secure (vs. anything that involves the internet).

The main reason for no radio is customer refuses any type of antenna due to numerous lightening strikes in the area. Cellular service is often interrupted during storms, therefore cellular is not an option.

If lightning strikes is a problem, then you better have an interface that will go from the modem to fiber optic back to wire signals.

Had a lightning strike run in thru the phone system and had to replace everything, including the fax machine.

james

Just because there is an antenna does not mean that it will get hit. Best practice is to use a surge suppressor which will protect everything from all strikes except those that hit the antenna directly and even then everything past the suppressor should be OK (a direct hit on an antenna usually means no more antenna). The most common type of lightning strikes are in-direct hits where the lightning strikes close by and there is an inducted surge in anything close by that conducts. By the way, that means that phone lines are just as susceptible as antennas are unless they are underground in a conduit that is protected.
Just an FYI.

jeremy_campbell said:

I have the need to control 4 remote stations from a central location. Remote stations are 6 miles from central. Remote stations have DL05 processors, centeral station will have Compact logix. Only existing lines are telephone, no internet at remote stations. Use of radio type devices (cell or anything with antenna) will not be allowed.

The remote stations will have a comms heartbeat, and get start/stop and 1 real number from central. Will need to tell central status of running and 2 real numbers.

Any ideas on how to accomplish this?

Click to expand...

Hello Jeremy,

We have 4 rtu's controlled from central station for a distance of 15 km and we used an ethernet dsl modem 3088 from patton using single pair of telephone cable and dnp3 protocol.

RET said:

Satellite comm is an option.

But not to allow radio...that's ridiculous. What's the reasoning behind that if you can say?

Click to expand...

Even satellite comms need a radio. Basically, there are four options:

1. Copper
2. Fiber
3. Radio
4. Laser (if line of sight)

rguimond said:

Even satellite comms need a radio.

Click to expand...

Yes, but it can be ground mounted.