Good morning,

First my apologies - this should be an easy fix, but I'm finding it difficult to configure the MM440 for this purpose. My main experience is with ABB drives.

I have a water pump that uses analog input 2 as frequency reference when selected to 'auto' mode. We have a facility to run the pump in 'manual/hand' mode with a resistor pot on the front of the starter panel. The resistor is connected to analog input 1. The digital input 1 is set to RUN (P701=1). This signal is provided by a relay in the starter panel. Digital input 2 wiring provides an 'auto' mode.

An electrician was changing the motor on the pump and during the process of changing the motor parameters in the MM440, he carried out a factory reset on the drive! I have no backup of the parameters on this drive and all other drives we have utilise Profibus.

I currently have the drive capable of running in 'auto' mode and analog input 2 is providing the correct frequency reference. However when I select 'manual/hand' mode, the frequency reference responds to the incorrect analog input.

How can I select via digital inputs, so that the frequency reference changes between analog 1 and analog 2? I have tried various settings but unable to figure it out. I suspect I need to use BICO settings but I'm so far not making much progress. 

Many thanks

Huw Jones

Hello,

Have a look at MICROMASTER 4 (MM4): Switch between two analogue inputs on MM4

Regards,

Marcjan

Huw,

I have attached a ppt. drawing for selecting between Analogue input 1 and Analogue input 2.

I also has a ppt for PI control pump pressure, I will look this out also.

Tractor

MM430 configuration will be the same as MM440.

Tractor

Good morning and thanks for the replies. 

The FAQ posted by Marcjan 'almost' works. However I'm using digital input 2 as the auto/manual changeover. When I try to change P810 from 722.2 to my desired value of 722.1, the AOP says 'incorrect parameter' and won't accept the change. I have my 'reset' button connected to DI3 and I can see when I press the reset, the setpoint changes. It's very close to working, but I can't figure out why the MM won't accept the change to P810. I have P702 set to 99 (BICO) and P703 is set to 9 (fault acknowledge). So I can't quite understand why the system sets DI3 as the CDS change. 

I tried quick commissioning to see if that reset the functionality of P810, but that didn't work. I guess it's something to do with the CDS? I tried setting P821=722.1 but that didn't help either.

Tractor: I tried the settings in your first PPT. It seems to be very similar to the FAQ but again, I can't change P810. I'm using an external PID so the second PPT you sent can't be used for this application. Much appreciated though, and I'll save it for my records.

The FAQ posted by Marcjan 'almost' works. However I'm using digital input 2 as the auto/manual changeover. When I try to change P810 from 722.2 to my desired value of 722.1, the AOP says 'incorrect parameter' and won't accept the change.

This will be because r722.1 is not made available.

r0722 is reading the inputs:

r0722.1 = Digital Input 1, terminal 5

r0722.2 = Digital Input 2, terminal 6

r0722.3 = Digital Input 3, terminal 7

etc

to make the digital inputs available make:

P0701 = 99, for terminal 5.

P0702 = 99, for terminal 6.

P0703 = 99, for terminal 7.

etc.

Then P0810 can accept the connection.

Bear in mind that once the digital input has been made 99, (available for BICO), it cannot be returned without making a factory reset.

Hope this bit helps with the understanding of this type of configuration.

Come back if I can help further.

Tractor

Yes, I believe the 'bridge' is open on Monday too.

Good luck with this snag.

And thanks for the feedback

Tractor

Huw

I have been having a look at this again, and hope I have been able to make this better.

I have assumed that both analogue inputs are Voltage?

Tractor

Good morning once again,

Thanks for your continued effort Tractor, much appreciated.

I have now managed to sort this problem. My continued issue was P810 not accepting the change to look at DIN2 (722:1). Even with Tractors most recent suggestion, P810 would not change. In the end, I carried out a factory reset and started from scratch. The first thing I did was change P810 = 722:1. I then carried out the procedure sent by Marcjan. I encountered a problem with the analog scaling but after the factory reset, AI1 & AI2 had reverted back to using voltage input. AI2 needed to be set as current input for my situation.

So my parameters have ended up being:

P700 = 2

P701=1

P702=99

P703=9

P756.0=0

P756.1=2

P810=722:1 

P1000.0=2

P1000.1=7

P1070.0=755.0

P1070.1=755.1

(Values for CDS 1+2 are the same unless otherwise stated)

It was only the pesky factory reset that was stopping me last week - the fast commissioning wasn't enough to clear P810. All is now back to normal and the AOP now has a backup of the parameters stored inside. 

Thanks again for the help.