2 or 4 or 8 channel analog multiplexer

Is there such a device to send 2 or more 4-20mA signals over a single pair cable, digitally or however it needs to a box on the other end that will split it back up to its analog form? The protocol it uses to send over the cable is irrelevant as long as the signals on the other end are intact and update at least once per second. Is there a wireless version of the same thing that will work over 300’ open air?

Google 'Wireless I/O' - I got a number of hits from big names in industry.

See link below.

http://www.miinet.com/InterfaceSolutionDownloadCenter/Products.aspx?product=191

Banner do some pretty good wireless stuff with there DX kit, or dependant upon the route you want to go, equipment you have ect, remote i/o modules are an option...

Wireless for the US only (because they're 900MHz):

1) Banner Engineering is a great radio for 2 (1W Performance) or 4 (DX-80 1/8W) analog I/O. It requires some amount of mapping the I/O (with Windows software) to assign which AI to which AO. AO's are active outputs, powered by the radio's 24Vdc power supply. Even the 1/8W radios will probably work at 300 feet with the 2dB antenna included with the radio.

To go more than 4 I/O points (wired-in/wired-out) requires a break-out box (DX-85) which requires some rather complex mapping procedures.

2) Phoenix Contact's two way 900MHz radio is what I call "electrician's radio". THere is no programming.

An input on module 1 at one end goes to a corresponding output on module 1 on the other end.
An input on module 2 at one end goes to a corresponding output on module 2 on the other end.

Take it out of the box, wire it to 24Vdc, wire an AI to a channel at one end, get a replicated AO on the output on the other end. AO's are loop powered, so the 24V supply that powers the radio is used to power the AO's, too. Modular I/O can be bussed one to another. Each module has up to 4 AI's or 4 AO's. Up to 8 modules or 32 I/O points.

At 300 feet, the little 1dB SS antennas will probably punch through.

Either Banner or PC does multiple updates per second.

These are great options. Thanks!

Are there any solutions for wired stuff?

No wired option that I'm aware of and I've kept my eyes open for such for years.

There are Modbus I/O modules with multiple AI's which could communicate over a pair of RS-485 wires to an AO module, but one of the two would have to be a dedicated Master, and I know of no I/O manufacturer who does that. All the modules are slaves, and Modbus slaves cannot talk to Modbus slaves.

Two PAC/PLC's with AI on one end, AO on the other could communicate over any number of digital protocols, but there's the cost of that 'complexity'.

danw said:

No wired option that I'm aware of and I've kept my eyes open for such for years.

There are Modbus I/O modules with multiple AI's which could communicate over a pair of RS-485 wires to an AO module, but one of the two would have to be a dedicated Master, and I know of no I/O manufacturer who does that. All the modules are slaves, and Modbus slaves cannot talk to Modbus slaves.

Two PAC/PLC's with AI on one end, AO on the other could communicate over any number of digital protocols, but there's the cost of that 'complexity'.

Click to expand...

The link I posted above appears to do that see link below page 4. Peer to peer.

http://www.miinet.com/Portals/0/DataSheets/NCS_Datasheet_Moore_Industries.pdf

have a look at arduino cheap but works.
i use WAGO plc for this
National instruments has devices.
search for data acquisition

chupa said:

Is there such a device to send 2 or more 4-20mA signals over a single pair cable, digitally or however it needs to a box on the other end that will split it back up to its analog form? The protocol it uses to send over the cable is irrelevant as long as the signals on the other end are intact and update at least once per second. Is there a wireless version of the same thing that will work over 300’ open air?

Click to expand...

Old school: Gavazzi's Dupline//Moore wiring concentrator.

Mickey said:

The link I posted above appears to do that see link below page 4. Peer to peer.

http://www.miinet.com/Portals/0/DataSheets/NCS_Datasheet_Moore_Industries.pdf

Click to expand...

Does it look like it needs 1 or 2 pairs for the peer to peer to work? Fig 3B makes it seem like Bidirectional is needed. But maybe if your only moving I from one side to O on the other 1 pair is enough?

For a wired multiplexer have a look at the Phoenix Contact IB IL 24 MUX MA-PAC http://catalog.phoenixcontact.net/phoenix/treeViewClick.do?reloadFrame=true&UID=2861205&parentUID==

Banner also do a DX70 module which doesnt need programming and is configurable for what is needed, good bit of kit, I used one for a lighthouse control system so it could be turned on remotley and the speed of the light could be altered using a VFD and 4-20ma signal

Mickey, thank you for pointing out that peer-to-peer function.

I've used other Moore Industries products but not this one; didn't recognize what it was.

In fact, I've got a project I can use a I/O Modbus slave module.

Thanks.

Dan

danw said:

Mickey, thank you for pointing out that peer-to-peer function.

I've used other Moore Industries products but not this one; didn't recognize what it was.

In fact, I've got a project I can use a I/O Modbus slave module.

Thanks.

Dan

Click to expand...

Let us know how it works out, as I have not used one myself. I have however used other products from them with great success. Their home office was just down the street from where I used to work. The boss had a real nice black Porsche parked out front.