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Hi,

For personal use I'm using a V280-18-B20B with a V200-18-E1B. snap-in module. In order to register temperatures, I'm going to use a (third party) Pt100 I/O-module which communicates via MODBUS RTU. 
According to the documentation I would have to configure comm. port 2 of the V280, through jumper settings, for RS485 communication. And, again according the documentation, these jumpers must be present on the circuit board directly behind comm. port 1 and port 2. But unfortunately in my case there are no jumpers on my V280 to set comm. port 2 to RS485.

Several questions popping up in my mind:

  1. Are there V280 models which don't have these jumpers to set comm. port 2 to RS485?
  2. Is the documentation incorrect and do I have to look better (and on a different place) on the circuit board?
  3. To communicate through RS485 with the V280, do I have to purchase the V200-19-RS4 Snap-in module (RS485 comm. board), because comm. port 2 is just not configurable for RS485 on the V280 (which I actually expect, because  the name at port 2 only indicates RS232. If port2 is also configurable for RS485, you would expect port2 to be labeled RS232/RS485).

In advance, thank you for your response.

 

L.

20201221_114753 (2).jpg

20201221_114844 (2).jpg

20201221_114805.jpg

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8 minutes ago, Leyke_1970 said:

To communicate through RS485 with the V280, do I have to purchase the V200-19-RS4 Snap-in module (RS485 comm. board), because comm. port 2 is just not configurable for RS485 on the V280 (which I actually expect, because  the name at port 2 only indicates RS232. If port2 is also configurable for RS485, you would expect port2 to be labeled RS232/RS485).

Yes, this looks to be the case. The two serial ports on the V280 are both RS232 and non-configurable. You can install the V200-19-RS4 module to add a configurable serial port for RS485. That module is very inexpensive.

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Remove the Snap I/O module and then using a flat blade screw driver remove the back portion of the V280's case.    There should be two sets of jumpers beside one set will control RS232/458 for port two the other set will control the RS485 termination for port 2.

 

See page 8 in the linked.

https://www.unitronicsplc.com/wp-content/uploads/2015/12/V230_260_280_290_INSTAL-GUIDE_12_15-2.pdf

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35 minutes ago, Cam said:

Remove the Snap I/O module and then using a flat blade screw driver remove the back portion of the V280's case.    There should be two sets of jumpers beside one set will control RS232/458 for port two the other set will control the RS485 termination for port 2.

 

See page 8 in the linked.

https://www.unitronicsplc.com/wp-content/uploads/2015/12/V230_260_280_290_INSTAL-GUIDE_12_15-2.pdf

I'm questioning that portion of the document. I think it may apply to the V290 only and not the V280. Unfortunately I only have a V290 here in my office and can't confirm on a V280. @Leyke_1970, please report back what you find.

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5 hours ago, Cam said:

Remove the Snap I/O module and then using a flat blade screw driver remove the back portion of the V280's case.    There should be two sets of jumpers beside one set will control RS232/458 for port two the other set will control the RS485 termination for port 2.

 

See page 8 in the linked.

https://www.unitronicsplc.com/wp-content/uploads/2015/12/V230_260_280_290_INSTAL-GUIDE_12_15-2.pdf

I know the documentation. But that's just it, my V280 says otherwise as the documentation. I already removed the back end. Believe me, there are no sets of jumpers on my V280.

If I get the time, I will take a picture of it.

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The V280 has evolved over the years of its existence since 2004.  The little door on the back and built-in RS485 didn't come along until about 2012.  The earlier units did not have native RS485.  You'll need the V200-19-RS4 module.  The V200-19-RS4-X isolated module is the current part number, $53 US from your friendly dealer. 

Or I saw an old -RS4 on the Ebay for $22.00.  I often wonder how many people get their hardware on eBay and then come here for tech support....

 

Joe T.

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1 hour ago, Joe Tauser said:

I often wonder how many people get their hardware on eBay and then come here for tech support....

I would like to add a few remarks to this ...

Positive consequences:

- in most cases, despite the respectable age of obsolete models of PLC Unitronics purchased on ebay  they are in working condition (+++++ to Unitronics brand);

- also in most cases it is possible to significantly upgrade the controller - sometimes even to a fairly modern version of the software;

- the ability to purchase a screen or keyboard of the controller as part of the used cheap PLC,  sometimes it is necessary to repair older production machines;

- the price that allows you to buy a controller or expansion module for experiments or training when its sale is not expected.

 

Negative consequences:

- modern documentation does not correspond to outdated models despite the same name (this case);

- there are incompatibilities of hardware and software versions (recently we studied on the forum why the new network card does not see by the outdated PLC);

- the absence of any guarantees that everything in the PLC is in working order, so it is clear that to build new machines on such old  PLCs is not recommended.

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8 hours ago, kratmel said:

V230.thumb.JPG.f808f2273b38ba2c83c8fd0815eaeea6.JPG

This is V230 jumper location - please check inside if no lable and cover is solid

 

Yeah. I definately don't have that.

like Joe T mentioned, i think i have a model before 2012 which did not come along with a configurable RS232/RS485 port.

So nothing left for me then to try to obtain a V200-19-RS4(X). The only problem is that I live in the Netherlands. Shipping costs via ebay is almost as expensive as the V200-19-RS4 itself. 

In the Netherlands I can only purchase this item if I had my own company (which is not the case 😀). But i figure something out.

Thank you everyone for your contribution in this item.

 

Leyke

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"The V280 has evolved over the years of its existence since 2004.  The little door on the back and built-in RS485 didn't come along until about 2012.  The earlier units did not have native RS485.  You'll need the V200-19-RS4 module.  The V200-19-RS4-X isolated module is the current part number, $53 US from your friendly dealer. 

Or I saw an old -RS4 on the Ebay for $22.00.  I often wonder how many people get their hardware on eBay and then come here for tech support....

 

Joe"

Just to confirm what Joe said, here is a comparison of two versions of a V280, note the jumpers behind port 2 on the right hand board...

image.thumb.png.861ef78d15e6150989e58feb7963e307.png

 

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1 hour ago, kratmel said:

It is another option - use PT100 sensor with embedded converter with analog output 0-10V or 4-20mA  and connect it to PLC ANALOG INPUT (3 item on i/0 board). 

I know, but I already have several devices for collecting temperature and humidity which work on the MODBUS protocol. So thank you for the reminder, but for now I stay with the option to find a V200-19-RS4.

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