Programming inputs and outputs on VFD

1168 Views 80 Replies 10 Participants Last post by dvcochran, 8 d ago

Funkadelicfred

Discussion Starter · 14 d ago

Trying to use a Schneider altivar 320 drive to turn its motor output off based on a 4-20 mA signal. I have read the drive programming manual many times but it really isn't very clear on exactly how to do this. Does anyone have any experience with Schneider drives?

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paulengr

· #2 · 14 d ago

Typically that's not how you do it. Run commands are typically a DIGITAL (on/off) command, not derived from analogs. You can wire a jumper to force a run command all the time and then just set it up so that 4 mA=0 Hz and rely on the low speed shut off. I'm more familiar with the 600 series where I can point to where it is but it's a basic drive/pattern setting.

The thing is that it won't be truly "off". The transistors will still be active. It just won't fire output pulses much, if at all. The better approach is to use the drive as intended where you use a digital input to signal run enable in 2 wire control mode and the 4-20 mA signal tells it what frequency to use.

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Funkadelicfred

Discussion Starter · #3 · 13 d ago

paulengr said:
Typically that's not how you do it. Run commands are typically a DIGITAL (on/off) command, not derived from analogs. You can wire a jumper to force a run command all the time and then just set it up so that 4 mA=0 Hz and rely on the low speed shut off. I'm more familiar with the 600 series where I can point to where it is but it's a basic drive/pattern setting.

The thing is that it won't be truly "off". The transistors will still be active. It just won't fire output pulses much, if at all. The better approach is to use the drive as intended where you use a digital input to signal run enable in 2 wire control mode and the 4-20 mA signal tells it what frequency to use.

I do have it running on digital I just have a low level sensor (someone ordered an analog one for some reason) that I want to use to disable the drive.

gpop

· #4 · 13 d ago

Easier to add a float or something else to take care of low level then use the analog sensor to control the speed of the drive so it slows down as it approaches the low level set point. Still have to keep a min speed of 16 htz or you risk burning the motor.

Another option would be a action pack set to convert a analog set point to a digital output but that's using a expensive part to fix another expensive part simply because you ordered the wrong part that was cheap.

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Funkadelicfred

Discussion Starter · #5 · 13 d ago

gpop said:
Easier to add a float or something else to take care of low level then use the analog sensor to control the speed of the drive so it slows down as it approaches the low level set point. Still have to keep a min speed of 16 htz or you risk burning the motor.

Another option would be a action pack set to convert a analog set point to a digital output but that's using a expensive part to fix another expensive part simply because you ordered the wrong part that was cheap.

OK yeah that's kind of what i thought of was just getting a different sensor. This one wasn't the cheap one either this one was super expensive and was supposed to communicate with a controller but that didn't happen.

And I don't need a speed reference either it's just a circ pump so it just runs at a set speed.

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micromind

· #6 · 13 d ago

In my experience, the more fancy the electronic gizmo is, the less likely it is to actually work. Almost always, the less complicated way is best.

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Funkadelicfred

Discussion Starter · #7 · 13 d ago

micromind said:
In my experience, the more fancy the electronic gizmo is, the less likely it is to actually work. Almost always, the less complicated way is best.

Oh yeah this stupid system was ridiculously overpriced for what it does.

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gpop

· #8 · 13 d ago

From helping you i must admit i learnt something.
Never order a Schneider altivar drive.

Last altivar i worked on was really old and did not have enough digital outputs so we did in fact use a vfd analog output then programmed the plc so anything 19.8ma or over was exceptionable as a "at speed" digital signal.

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micromind

· #9 · 13 d ago

Funkadelicfred said:
I don't need a speed reference either it's just a circ pump so it just runs at a set speed.

A lot of VFDs have constant speeds, usually more than one, You can program any of them to any speed you want then program one of the digital inputs to that constant speed.

If the VFD does not have constant speeds, you can program the jog to the speed you want and program a digital input for jog.

FisherElectricAutomation

· #10 · 13 d ago

gpop said:
From helping you i must admit i learnt something.
Never order a Schneider altivar drive.

Last altivar i worked on was really old and did not have enough digital outputs so we did in fact use a vfd analog output then programmed the plc so anything 19.8ma or over was exceptionable as a "at speed" digital signal.

Altivars are fine for a mid-market product and even better with a stocking dealer minutes up the road when rockwell is still taking weeks to fulfill.

Fred have a look at pages 137-139 for the analog input config and deadband in the 320 programming manual. I don't have enough information to recommend anything else at this time. Unsure if you're attempting to fill or drain the tank with your circulation pump or why level is in play, if not.

Funkadelicfred

Discussion Starter · #11 · 13 d ago

FisherElectricAutomation said:
Altivars are fine for a mid-market product and even better with a stocking dealer minutes up the road when rockwell is still taking weeks to fulfill.

Fred have a look at pages 137-139 for the analog input config and deadband in the 320 programming manual. I don't have enough information to recommend anything else at this time. Unsure if you're attempting to fill or drain the tank with your circulation pump or why level is in play, if not.

I did read that section as well as the others but they don't let me change what that input does. It won't let me program it in the I/O section and then I was checked the Control section and it didn't work in there either and I don't know.

I just want it as a failsafe so if the sensor is uncovered and reading 4 mA then the pump will shut off.

gpop

· #12 · 13 d ago

Funkadelicfred said:
I did read that section as well as the others but they don't let me change what that input does. It won't let me program it in the I/O section and then I was checked the Control section and it didn't work in there either and I don't know.

I just want it as a failsafe so if the sensor is uncovered and reading 4 mA then the pump will shut off.

You might be able to fault the drive with a analog out of range but that's going to cause all sorts of troubleshooting problems.

Take a look at a smart relay (programmable) or a threshold value switch. My normal go to in these situations is a red lion panel display with alarm relays as we have spares onsite plus we would only be using a analog sensor if we wanted to display the level.

Funkadelicfred

Discussion Starter · #13 · 13 d ago

gpop said:
You might be able to fault the drive with a analog out of range but that's going to cause all sorts of troubleshooting problems.

Take a look at a smart relay (programmable) or a threshold value switch. My normal go to in these situations is a red lion panel display with alarm relays as we have spares onsite plus we would only be using a analog sensor if we wanted to display the level.

Yeah I already had the hell of a time figuring out why the sensor wasn't outputting voltage anyway. I figured a level sensor would always be off on so I had it done digitally and nothing worked. Tried it on analog and found out that's how it worked. No idea why it's like that but I guess the fact that it only had 2 wires should have clued me in.

Funkadelicfred

Discussion Starter · #14 · 12 d ago

gpop said:
You might be able to fault the drive with a analog out of range but that's going to cause all sorts of troubleshooting problems.

Take a look at a smart relay (programmable) or a threshold value switch. My normal go to in these situations is a red lion panel display with alarm relays as we have spares onsite plus we would only be using a analog sensor if we wanted to display the level.

I would love to learn more about smart relays. They're basically PLC's with far more limited capabilities right? So you'd still need software to program them?

FisherElectricAutomation

· #15 · 12 d ago

Funkadelicfred said:
I would love to learn more about smart relays. They're basically PLC's with far more limited capabilities right? So you'd still need software to program them?

probably wouldn't bother with a zelio for a few dollars more you can get a modicon m221 also with free software. Automation direct clicks also use a free software I recall

gpop

· #16 · 12 d ago

Funkadelicfred said:
Yeah I already had the hell of a time figuring out why the sensor wasn't outputting voltage anyway. I figured a level sensor would always be off on so I had it done digitally and nothing worked. Tried it on analog and found out that's how it worked. No idea why it's like that but I guess the fact that it only had 2 wires should have clued me in.

That piece of paper that comes in the box sometimes is worth reading .... lol

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Funkadelicfred

Discussion Starter · #17 · 12 d ago

FisherElectricAutomation said:
probably wouldn't bother with a zelio for a few dollars more you can get a modicon m221 also with free software. Automation direct clicks also use a free software I recall

It's about availability for me. I'm in rural Canada and Allen Bradley and a lot of stuff is unavailable to me so we end up with Schneider a lot.

Funkadelicfred

Discussion Starter · #18 · 12 d ago (Edited)

gpop said:
That piece of paper that comes in the box sometimes is worth reading .... lol

Wasn't in there literally. Had to look it up on the website. The manual just said to power it with 24V DC.

CraziFuzzy

· #19 · 11 d ago

Funkadelicfred said:
I did read that section as well as the others but they don't let me change what that input does. It won't let me program it in the I/O section and then I was checked the Control section and it didn't work in there either and I don't know.

I just want it as a failsafe so if the sensor is uncovered and reading 4 mA then the pump will shut off.

Any 'failsafe' should be independent of the 'normal' control method - otherwise it's not actually a failsafe (meaning a failure of the normal sensor).

CraziFuzzy

· #20 · 11 d ago

Any extra info you can provide about that actual process happening here?

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