# Only GE would be dumb enough......



## Jlarson (Jun 28, 2009)

It's Garbage Electric, such absurdity is to be expected. :laughing:

I'm pretty sure I had the same issue with some GE drives, probably the same model, and I just took the 0-10 output to a signal conditioner, no ripoff analog cards needed.


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## micromind (Aug 11, 2007)

Jlarson said:


> It's Garbage Electric, such absurdity is to be expected. :laughing:
> 
> I'm pretty sure I had the same issue with some GE drives, probably the same model, and I just took the 0-10 output to a signal conditioner, no ripoff analog cards needed.


I suggested that, but the higher-ups decided they wanted the card. 

Oh well....


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## Jabberwoky (Sep 2, 2012)

I think I missed something. Why do you need a current output instead of voltage for the I/O? 

I have to admit that there are some things I don't like about the GE VFDs but man some of their components lasted. I remember taking out some buss caps dated in the late 1960s of a drive that ran at least 6 months out of the year for 40+ years. I rebuilt a few of those drives that were used for a good portion of those 40 years from that company. I'd say they got more than their money's worth from those.


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## MDShunk (Jan 7, 2007)

Jabberwoky said:


> I think I missed something. Why do you need a current output instead of voltage for the I/O?


Probably because it's 2012 and not 1987. Just a guess. :thumbsup: Myself, I'd prefer Ethernet or Devicenet comms.


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## ampman (Apr 2, 2009)

Jlarson said:


> It's Garbage Electric, such absurdity is to be expected. :laughing:
> 
> I'm pretty sure I had the same issue with some GE drives, probably the same model, and I just took the 0-10 output to a signal conditioner, no ripoff analog cards needed.


what is a signal conditioner


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## MDShunk (Jan 7, 2007)

ampman said:


> what is a signal conditioner


A generic term for any device that takes one type of signal and turns it into another. A 4-20 to 0-10 (and vice versa) is probably the most common.


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## JRaef (Mar 23, 2009)

You can turn a 0-20mA output into a 0-10VDC output with a dropping resistor, but you can't go the other way, as you need to. A signal conditioner takes care of that and that's all that card is going to be, except it will be powered by the drive. If you were to use a stand alone signal conditioner, you would also need a power supply for it so most likely when you count your labor, this is costing less (to them).

In 1987, GE made their drives. Now theses are GE in name only, they are all Fuji drives. Fuji makes good drives, and Fuji makes cheap drives. Pick one.

The current regulating op-amp for a 4-20mA output is more expensive than the simple resistance op-amp needed for 0-10VDC, thats why cheaper drives dont provide it, they are all about the price. That's true for most cheap drives, and 90% of the time, all they are driving with the output is a cheap little analog meter. The cheapest little analog meters are DC voltmeters, hence the cheap output allows for cheap metering. See the trend here?


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## Jabberwoky (Sep 2, 2012)

MDShunk said:


> Probably because it's 2012 and not 1987. Just a guess. :thumbsup: Myself, I'd prefer Ethernet or Devicenet comms.



Can you be more specific? Unfortunately 1987 would be modern tech for most of the equipment I work on. They cringe anytime I ask for an update on PLCs. Come to think of it the only piece of gear on our lines that are less than 20 years old are the Pro-face screens.


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## Jlarson (Jun 28, 2009)

micromind said:


> I suggested that, but the higher-ups decided they wanted the card.
> 
> Oh well....


:laughing:



ampman said:


> what is a signal conditioner


They are handy little things, RTD to 4-20 ma, TC to 0-5 v, 0-5 v to 4-20 ma... just about anything imaginable. 

You can get ones that have relay outputs too, they come in really handy to say add a pressure transducer or a ultrasonic level sensor that is 4-20 ma output to a relay system. 



JRaef said:


> If you were to use a stand alone signal conditioner, you would also need a power supply for it so most likely when you count your labor, this is costing less (to them).


It probably be about the same price when the dust settles but using conditioners is better cause you don't have to give GE more money.


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## I_get_shocked (Apr 6, 2009)

Whats wrong with using the 0-10? Works all the same in the end


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## JRaef (Mar 23, 2009)

I_get_shocked said:


> Whats wrong with using the 0-10? Works all the same in the end


4-20mA is more noise immune if you have to go any distance, but if you are just running up to a meter in the same panel, you're right.


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## JRaef (Mar 23, 2009)

Jlarson said:


> ...It probably be about the same price when the dust settles but using conditioners is better cause you don't have to give GE more money.


Well, there's that for sure.:yes:


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## micromind (Aug 11, 2007)

I_get_shocked said:


> Whats wrong with using the 0-10? Works all the same in the end


This installation involves PLC controls, and the PLC will accept only 4-20. 

I don't know if it's an industry trend or just a local thing, but just about every analog control I've worked with in the last 20 years has been 4-20. 

You'd think a company the size of GE would 'get it', but as noted, it costs less to build a drive with only a voltage output vs. current.

The owners of this plant will very likely add on in the future, I'm pretty sure that with the extra expense (both labor and material), they'll go with something other than GE for the next one. 

Even though GE was low bid, I seriously doubt it was the best value once it is all said and done.


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## I_get_shocked (Apr 6, 2009)

Most of the controllers I work with accept either 4-20ma, RTD/Thermistor, or 0-10vdc for analog input. Every VFD I have installed has brought feedback into a 0-10v input unless it was communicating over fieldbus (modbus, bacnet, N2, etc) though I am sure the drive could be configured for 4-20. 

Its my preference to use 0-10v. I haven't had any issues with VD or noise and we only use shielded cable. For me, its easier to troubleshoot - everyone's meter can read VDC while only some meters will read mA. I also tend to see some control electricians struggle with understanding 4-20ma and neglect to set jumpers correctly etc.


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## gesparky221 (Nov 30, 2007)

Ge Drives are now made by Danfoss. At first I had alot of issues changing from the Fuji drives to the Danfoss but I have become comfortable using them. Of course we have to use GE as we should so I am not able to compare other drives.


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## Peewee0413 (Oct 18, 2012)

I have been curious about danfoss drives. Not sure if I wanna give up on A-B though.


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## Jabberwoky (Sep 2, 2012)

I_get_shocked said:


> Every VFD I have installed has brought feedback into a 0-10v input unless it was communicating over fieldbus (modbus, bacnet, N2, etc) though I am sure the drive could be configured for 4-20.
> 
> Its my preference to use 0-10v. I haven't had any issues with VD or noise and we only use shielded cable. For me, its easier to troubleshoot - everyone's meter can read VDC while only some meters will read mA. I also tend to see some control electricians struggle with understanding 4-20ma and neglect to set jumpers correctly etc.


Yeah I can't recall many VFDs that even are capable of using 4-20ma for a reference with the default I/O. Most do have selectable analog outputs for 4-20ma. Most systems I have come across use 0-10 for everything except maybe the old analog needle meters and the occasional long runs over 100ft.

Its so much faster trouble shooting the 0-10 too. Disconnecting the line to insert a DMM or wraping the wire 10 times around a clamp-on are usually either impractical or impossible. I thought perhaps there was some other design consideration for 4-20ma that I did not know.


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## Peewee0413 (Oct 18, 2012)

I can see how some of the old school guys can have issues with 4-20 , but that's what I find best. Im a young gun so to say. And as far as meters go, if you don't own a 789 your no tech.. go wire up houses lol. That was the second meter I ever bought. It does it all.


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## Peewee0413 (Oct 18, 2012)

Plus in 0-10 the ten isn't there downsides that 4-20 don't have? I was told by my "mentor" years ago that they both have the same +'s but I fo
rgot what the 0-10 lacks. Input anyone?


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## JRaef (Mar 23, 2009)

Both have their uses.

0-10VDC is less noise immune and can suffer from voltage drop if too long. So it is typically used when the signal does not have to go outside of the same enclosure or at least not far away, like 10' or less. 0-10VDC does however make it easier to read with a simple voltmeter, as long as you understand that the act of reading the value may affect the signal itself.

4-20mA is better for long runs and noise immunity on circuits that must leave the box. But reading it requires lifting a wire and putting the meter in series, something some people are loathe to do or it cannot be done if it interrupts the process flow. To get around that, some people use 4-20mA as the control signal and install a signal conditioner in series with it just to give them a 0-10VDC value to read without stopping the process. You can also use special terminal blocks that allow you to install the meter probes with the signal intact, then open a built-in little knife switch to run it through the meter.

PS: Thought of one more thing. On a 4-20mA signal, you can set up an alarm that says that if the signal ever drops below 4mA, you have a broken wire or failed device. In a 0-10VDC signal, if the wire breaks you just get a minimum signal.


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## Peewee0413 (Oct 18, 2012)

Fluke has a newer meter that is a clamp around 4-20 I know it works my company bought one years ago from a fluke rep... and compared with a 789 and its right on.


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## micromind (Aug 11, 2007)

I have Fluke 771; it's a 4-20 clamp-on. 

A real timesaver.....plus, during commissioning, it'll tell you if the problem is toward the PLC or toward the field without disconnecting anything. 

The only two drawbacks I've seen so far is it'll turn itself off after a certain amount of time (I don't think it can be programmed not to) and it wanders a bit, but it's easy to zero out. 

I wouldn't recommend it for precise measurement, but for a fairly close estimate of current, it's great.


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