regarding replaceing DAQ with Arduino

Hello Guys, currently I am using NI DAQ for controlling 21 relays. but I need DAQ for different project, so I need to release it. And I am new to Arduino. But I see lots of material available. So it might be good idea to replace DAQ control with Arduino. I need quick and fast solution. My question: is arduino have power to control 21 relays simultaneously. These relay controlling for DC supply components. If yes, which ardino model will be useful. please guide me, it will be grate help. Thanks in advance, Aishwari.

NI-DAC is that National Instruments ?

the Arduino had a 10 bit resolution. not sure what resolution your intputs are. you can use a chip to increase that very easily.

you say simultaneously, but currently the NI-DAC and the Arduino do sequential reads and writes. without knowing your particular devices for reading we cannot offer more than general comments.

as for controlling 21 relays, that is no problem.

Hi, Welcome to the forum.

What is the application? As asked what resolution do you need on the AtoD and how many analog inputs do you need?

Can you post link to NI-DAC that you have please.

Thanks.. Tom.... :)

dave-in-nj: NI-DAC is that National Instruments ?

the Arduino had a 10 bit resolution. not sure what resolution your intputs are. you can use a chip to increase that very easily.

you say simultaneously, but currently the NI-DAC and the Arduino do sequential reads and writes. without knowing your particular devices for reading we cannot offer more than general comments.

as for controlling 21 relays, that is no problem.

Hi.. Thanks for your reply. yes its National instrument.

I my case Simultaneously means more relays will work at same time, for example two relays will working at same time.

And my DAQ ni PCI 6220 working fine. But due to resource issue i hv to change it. As per your last statement I can use arduino to control 21 relays. So my I know which arduino model (kit) is good option?

Hi, How many inputs do you need?

Tom... :)

TomGeorge: Hi, Welcome to the forum.

What is the application? As asked what resolution do you need on the AtoD and how many analog inputs do you need?

Can you post link to NI-DAC that you have please.

Thanks.. Tom.... :)

aishtalhan: Hi, How many inputs do you need?

Tom... :)

Thanks for your replay.. To be more specific... I need control on 21 relays. Some of them will work at a time. The components which I want to operate are air valves which works on digital supply. some valves work on 5 v DC and and some 12 V dc, What I expect from arduino is control over 21 relays... Is it possible?

Hi, How many inputs do you need?

Tom... :) [/quote]

Hi, How many inputs to the controller do you need, how many inputs do you use in the DAQ ni PCI 6220? NOT OUTPUTS I know you need to output to 21 relays.

Tom... :)

TomGeorge: Hi, How many inputs to the controller do you need, how many inputs do you use in the DAQ ni PCI 6220? NOT OUTPUTS I know you need to output to 21 relays.

Tom... :)

8 inputs!

Hi, Are they analog or digital or a combination. The arduino controllers depending on model have differing numbers of digital and analog inputs available.

Phew........ :o Tom.... :) Can you tell us your electronics, programming, arduino, hardware experience?

all are digital ..

I have programming experience for c, c++. However I never used arduino before. But seems to be easy to control as i show my programs online...

TomGeorge: Hi, Are they analog or digital or a combination. The arduino controllers depending on model have differing numbers of digital and analog inputs available.

Phew........ :o Tom.... :) Can you tell us your electronics, programming, arduino, hardware experience?

currently all are digital ..

I have programming experience for c, c++. I am working currently on hardware control unit...so i will learn..

You can use Arduino MEGA which have 54 digital I/O pins, 16 analog inputs.

For relay you can use Arduino Relay Shield like this |500x500 |500x400

BillHo: You can use Arduino MEGA which have 54 digital I/O pins, 16 analog inputs.

For relay you can use Arduino Relay Shield like this |500x500 |500x400

Thanks for replay... I am gonna check it..

Thanks :)

I think we are not communicating.

you can control 64 relays, even more, 128, maybe 512.... any one or any combination, 1 on, 3 on, 184 on at the same time.

HOW do you know when to turn them on ?

the Arduino UNO has an analog input that is 10 bit. that means it can see an analog value and it will turn it into 1024 slices.

if you just want to have on switch, ON = all relays OFF, switch OFF = all relays ON, that is very easy.

if you want to measure the output of a sensor and from 2 volts to 2.0000001 volts turn on 5 relays and at 2.0000002 volts, turn on another relay, then you have to add things to allow you to see the very high resolution inputs.

the answer is YES, you can control hundreds of relays, any combination, turn any one or any number ON or OFF, 100,000 times a second. the relays will fail as they cannot move that fast.

YES, you can turn 10 on today and turn 5 off tomarrow and turn 7 more on next wednesday or turn 7 on when you see the letter a A and turn 3 off and 8 more on when you see the letter b B

our question is HOW to you know when to turn them on ? how are you measuring INPUTS ?

BillHo: You can use Arduino MEGA which have 54 digital I/O pins, 16 analog inputs.

For relay you can use Arduino Relay Shield like this |500x500 |500x400

actually, not good.

each board has an opto. 10mA per input.

although the maximum power is the sum of all 24 channels at one time are high is lower than the theoretical limit of the outputs, it is too close for comfort.

it would be better to have a serial addressable interface.

not sure why no one does that.

Hi,

http://www.iascaled.com/store/I2C-RELAY16

This looks like a I2C board that can be used to interface with 16 relays. Even has arduino library and examples.

Tom..... :)

dave-in-nj: actually, not good.

each board has an opto. 10mA per input.

although the maximum power is the sum of all 24 channels at one time are high is lower than the theoretical limit of the outputs, it is too close for comfort.

it would be better to have a serial addressable interface.

not sure why no one does that.

The board doesn't really use those 10mA per channel, but only 4mA, which makes it possible to use it directly for the Arduino's outputs

Arduino Mega to 16 channel relay board

BillHo: The board doesn't really use those 10mA per channel, but only 4mA, which makes it possible to use it directly for the Arduino's outputs

Arduino Mega to 16 channel relay board

according to the manufacturer, SainSmart :

16-Channel Relay interface board, and each one needs 15-20mA Driver Current

you and I both know you MAY drive an opto with lower currents, but the manufactuers's spec is for 15 to 20mA per channel but you and I both know that you have to review the data sheet for the opto to see what the response is and what the lowest reliable currrent is. AND we know that from lot to lot the manufacture can swap opt's with the cheap chip of the weak.

15mA x 24 channels is only 360 mA output. 5mA x 24 is 120mA

my point is that for 24 channels, you have to have 24 pins. OR, use a port expander or shift register. as soon as you move over to a serial device, all the load is shifted to that device.

it would make sense to make the relay board with the serial device as the input.

and of course you can just make an interface board with a slew of 2N7000 FET's and use almost no power.

dave-in-nj: I think we are not communicating.

you can control 64 relays, even more, 128, maybe 512.... any one or any combination, 1 on, 3 on, 184 on at the same time.

HOW do you know when to turn them on ?

the Arduino UNO has an analog input that is 10 bit. that means it can see an analog value and it will turn it into 1024 slices.

if you just want to have on switch, ON = all relays OFF, switch OFF = all relays ON, that is very easy.

if you want to measure the output of a sensor and from 2 volts to 2.0000001 volts turn on 5 relays and at 2.0000002 volts, turn on another relay, then you have to add things to allow you to see the very high resolution inputs.

the answer is YES, you can control hundreds of relays, any combination, turn any one or any number ON or OFF, 100,000 times a second. the relays will fail as they cannot move that fast.

YES, you can turn 10 on today and turn 5 off tomarrow and turn 7 more on next wednesday or turn 7 on when you see the letter a A and turn 3 off and 8 more on when you see the letter b B

our question is HOW to you know when to turn them on ? how are you measuring INPUTS ?

Thanks for the reply. In my application, everything depends on the user. every control is in user's hand. I want when the user asks to ON/OFF the specific relay should get ON/OFF. This should be controlled by the user interface. Currently, my program is just using command line interface. However, in future, I need to extend it with graphical user interface. So, is it possible with Arduino programming? Thanks...

Hi, GUI from what platform. If its Windows based, Processing will let you make a GUI and communicate with the arduino via the USB programming cable.

google Arduino Processing

Tom.. :)