xtr110

Ian

Cheers,

We have pressure transmitters & temperature transmitters.

Models:

1.     Rosemount Pressure transmitters- 3051

2.     Rosemount Temperature transmitters- 3114

I want to simulate them or emulate. However replace them with the 4-20mA device.

They use the same 2 wire to get power as well transmit the signal & run a LCD.

The burning question, how do they achieve this?

1.     Power up the micro

2.     Run a LCD

3.     And transmit a signal all on a 2 wire system, that carries 20mA current max.

From the research, I realized the micro & LCD uses the first 4mA to power up and 4 -20mA for the signal

As for the total design:

On the sensor end,  it could be a device like XTR116 or XTR105

On the other end , (the PLC side) what device will that be?

As for the XTR110:

This was used on a Analog output card which caught my interest.

Cheers

Richard

Richard,

We offer a 4-20mA receiver, the RCV420, which is a fully-integrated solution for converting 4-20mA to 0-5V. It offers high accuracy, flexible power supply requirements, and requires no external components except for decoupling capacitors.

Let me know if this device is of interest to you. If converting 4-20mA to 0-5V on the receiving side is not suitable for your application, let me know your requirements and we can work from there.

Cheers,

Ian Williams

Yes, Fantastic

It could be a RCV on the receiving end & XTR105 on the transmitting end.

For the transmitting end there would be a 0-5 voltage input generated from a micro and possibly via a DAC.

 Cheers

Richard  

Richard,

One thing to keep in mind - the micro and/or DAC used as input to the XTR must be powered from the XTR's onboard regulator and referenced to the XTR's Iret pin in order for the 4-20mA loop to function properly. The XTR105 can only source 1mA from its regulator, so if more power is required for your input circuitry you should select a different XTR part that has more current drive available from its regulator. For example, the regulator of the XTR112 can source 2.1mA and the XTR114 can source 2.4mA.

Cheers,

Ian

Ian

So,  that power source in each case is generated directly from the 4-20mA loop. Is the right?

I would look up the datasheets & come up with a proposal.

Cheers

Richard

Richard,

That is correct. Everything on the transmitter side is powered only from the 4-20mA loop. The current draw from the input circuitry must not overload the XTR's regulator, since if it does the minimum-scale current output will be pushed higher than 4mA depending on how much excess current is drawn.

Cheers,

Ian

Ian

It's becoming clear now.

Can I buy few devices only instead of a reel or tube? Better still, can I get samples?

Cheers

Richard

Richard,

Of course you can. All of the devices we've discussed are part of our free sample program. Simply click "Sample and Buy" on the homepage at www.ti.com and you can order samples for whichever parts you're interested in.

If you have any trouble, please let me know and I'll help you get what you need.

Cheers,

Ian

I requested for samples. Sample parts were not not the same part numbers as we discussed in the past .

Heres the list of samples. XTR110, XTR105 & RCV are not included. How can I get these parts? The sales request has a MoQ that is only for production.

Attached here is the proposal & intension of design. Please review & make comments.0083.Protel Block Schematic 4-20mA.pdf

Heres the list

Regards

Richard

Richard,

My apologies on the confusion regarding the samples. The different part numbers such as "XTR111AIDRCT" include suffixes for package type and shipping method (cut tape, reel etc.)

I was unaware that as a TI employee I was automatically given expanded options in the sample store, even without logging in. Please let me know the quantity and package type desired for your samples of XTR105, XTR110, and RCV420. I will also need your shipping address, e-mail address and phone number to complete the shipping form - please e-mail me this information at ian@ti.com.

As for the block diagram, it looks good to me but I have a few questions/comments:

1. The top row looks good. A "smart device" is being used as input to the XTR105, and I assume the XTR105 regulator is used to power this device. The 4-20mA output from the XTR105 is converted to 0-5V by the RCV420 to become input for the main microcontroller.
2. I'm curious about the second row. It seems like the XTR110 is being controlled by a secondary micro and/or DAC, and the 4-20mA output is converted to 0-5V by another RCV420. The text by the RCV420 that says "Generates a current source for the 4-20mA" is incorrect in this case, since the XTR110 draws current from its own power supply. The XTR110 also has no voltage regulator output, so the micro controlling it must have external power provided as well. I see the text "With external PSU" next to the XTR110 block, so I assume this is taken care of.
3. The third row seems straightforward, but I can only see "XTR11" in the block next to the main micro so I'm not sure if an XTR110 or XTR111 is being used. I assume a XTR110, is this correct? 

Best regards,

Ian Williams

Ian

You're correct on all counts.

As for the block diagram, it looks good to me but I have a few questions/comments:

1. The top row looks good. A "smart device" is being used as input to the XTR105, and I assume the XTR105 regulator is used to power this device. The 4-20mA output from the XTR105 is converted to 0-5V by the RCV420 to become input for the main microcontroller.  Yes the XTR105 regulator is used for power to a local micro & LCD. No external power required.
2. I'm curious about the second row. It seems like the XTR110 is being controlled by a secondary micro and/or DAC, and the 4-20mA output is converted to 0-5V by another RCV420. The text by the RCV420 that says "Generates a current source for the 4-20mA" is incorrect in this case, since the XTR110 draws current from its own power supply. The XTR110 also has no voltage regulator output, so the micro controlling it must have external power provided as well. I see the text "With external PSU" next to the XTR110 block, so I assume this is taken care of. Text by the RCV420 is a typo (was a copy&Paste).  No need for it to generate a power source. Yes, XTR power is taken care of by the external PSU which also powers a local micro & LCD.
3. The third row seems straightforward, but I can only see "XTR11" in the block next to the main micro so I'm not sure if an XTR110 or XTR111 is being used. I assume a XTR110, is this correct?  Yes, Typo again, should be XTR110.

Thanks, I will update the block & re-send. I will also send my details directly.

Regards

Richard

Ian

Here is the updated block diagram.

3362.Protel Block Schematic 4-20mA.pdf

Regards

Richard

Ian

Thanks for fast tracking the samples. All samples have arrived.

Regards

Richard

Richard,

I am happy to hear that you received the samples quickly. I am marking this thread as closed.

Please create a new thread if there are any questions while evaluating these XTR and RCV devices.

Best regards,
Ian