Netbotz 570, digital inputs, extend digital inputs

DCIM_Support · ‎2020-07-05

This question was originally posted on DCIM Support by Alex Rente on 2018-11-15

Hello experts,

I was not able to find information anywhere on the internte, so i hope that you can help me.

My task is to monitor our air conditioning system in our data center with the help of Netbotz 570. The connection of analog sensors is very clear and understandable but not the connection of digital inputs.

The air conditioning itself has serveral digital outputs ( for examlpe , tower 1 is working > sending bit 0 or 1)

I need digital inputs on the netbotz to process the data. The netbotz has 6x(0-5V) analog input. I could connect them with the help of their respective cable, but i think it is not to supposed to be. I also couldnt find extended modules or sth like this...

I hope you can help me 😃

Have a nice day

Alex

DCIM_Support · ‎2020-07-05

This answer was originally posted on DCIM Support by Steven Marchetti on 2018-11-15

Hi Alex,

Sorry but there are no digital input options for the NetBotz wired sensors. As you mentioned, there is a 0-5v, there is also a 4-20 mA as well as dry contact. None of these are digital. There is voltage, amperage, and basically an on/off switch.

The digital options are NetBotz monitoring using SNMP or IPMI. I believe SNMP would be your only option here but that may take too long for your purposes (5 minute poll time).

Thanks,

Steve

DCIM_Support · ‎2020-07-05

This answer was originally posted on DCIM Support by nanoman on 2018-11-15

Hi, I don't see why use cannot use the analog in for measuring the digital 1 and 0. Digital 0 (low) and 1 (high) are just voltage ranges.

Just use the analog in with appropriate threshold value (say 2.0 Vdc).

Simply use a Voltmeter to measure/verify the tower output on "1" tower working and off "0" tower not working. After measuring the output, set appropriate threshold.

If you would like you could add a buffer/opto isolator between the tower output and botz input, but not necessary.

DCIM_Support · ‎2020-07-05

This comment was originally posted on DCIM Support by Steven Marchetti on 2018-11-15

NetBotz treats the voltage as an analog measurement. If there are digital readings, usually there are multiple 0s and 1s as in a binary number (digital, 0s and 1s) and that's the way I understood the question.

If it is simply a voltage or non-voltage, you can set that to read as a measurement of 0v = 0 reading and 2v = 2 reading and simply alert when the value is above 1. If there are multiple readings in this single "digital" device output being read by the same cable and the value of each "bit" changes the voltage by the same value, there is no way to differentiate between the 2.

DCIM_Support · ‎2020-07-05

This comment was originally posted on DCIM Support by nanoman on 2018-11-15

Yes, digital can mean a simple state On/off, a data stream or "0" and "1" , a pulse (one shot for transition of state), etc.. I would think the tower status is simply a state indicator (that is, either 1 or 0). In my case, I have a stack fan that just outputs a logic one (1) or zero (0) for status, not a data stream. I am not even sure how the botz with handle a data stream. If it simply a pulse, a edge detecting relay could be used in combination with Botz dry contact input.

DCIM_Support · ‎2020-07-05

This comment was originally posted on DCIM Support by Steven Marchetti on 2018-11-15

That's my point...the bot can't handle a data stream. A simple voltage or no voltage is easy.

DCIM_Support · ‎2020-07-05

This comment was originally posted on DCIM Support by nanoman on 2018-11-15

if It is a "datastream". Say its a 8 bit digital signal with 2 bit being one of interest (status of on/off), a shift register could be easily used to isolate the 2 bit and feed the botz analog input.

DCIM_Support · ‎2020-07-05

This comment was originally posted on DCIM Support by Alex Rente on 2018-11-16

Thank u guys for the answers. Nanoman understood me right. I just got a single wire ( 0-24V) from the aircon and need therefore just two different states.

"If it is simply a voltage or non-voltage, you can set that to read as a measurement of 0v = 0 reading and 2v = 2 reading and simply alert when the value is above 1." ( Steven Marchetti)

That would be the method, I also thought about ! And I thought before, that would be the only possible solution. But it is some kind of misuse but what ever.

Now i got just two left questions:

As you can read above, i got 0-24V output from the aircon, can i just connect it to the 0-5V input? Probable not, so I need a voltage converter?!
I would need a lot more 0-5V inputs. Is there a possibility to extend those? ( Any solution on this would be helpful, did not found sth on the net. Just stack more Netbotz´s...., but this would be very expensive and effortful.

Best regards

Alex

DCIM_Support · ‎2020-07-05

This comment was originally posted on DCIM Support by nanoman on 2018-11-16

Alex,

There are many ways to scale to voltage. Presuming its simple DC voltage a simple voltage divider would work. That is, buy two (2) resistors and hook up in series. Use resistor next to ground to feed the botz. The resistors have tolerance for the ratio would be a little different. I don't use nay resistor below 1/4 watt. Of course, this does not account for the input impedance of the Botz ( I believe it would be many mega ohms).

The 0-5 V sensor does not list its input impedance but I would presume its on the order of 10 Megohms. If so the voltage divider would work.

https://www.apc.com/shop/us/en/products/NetBotz-0-5V-Cable-15-ft-/P-NBES0305

DCIM_Support · ‎2020-07-05

This comment was originally posted on DCIM Support by nanoman on 2018-11-16

A clearer circuit with return path.

DCIM_Support · ‎2020-07-05

This comment was originally posted on DCIM Support by Alex Rente on 2018-11-20

Ok, thats clear to me. Second question is still open 😂

I would need a lot more 0-5V inputs. Is there a possibility to extend those? ( Any solution on this would be helpful, did not found sth on the net. Just stack more Netbotz´s...., but this would be very expensive and effortful.

DCIM_Support · ‎2020-07-05

This comment was originally posted on DCIM Support by nanoman on 2018-11-20

Alex, for clarity

Q1. how many inputs do you need?

Q2. Are they all basic on/off status indicators (24 or 0 vdc)?

Q3. Does the Botz need to identify / notify which one is off or can it group multiple inputs into a failure? For example, 4 inputs flag/ notify if any one is off.

I like the Botz, but it may not be your solution. Possibly use a Barix Barionet 100 Programmable I/O Device Server or similar in combination with Botz. The barionet would monitor the aircon status and feed the Botz. The Barionet has 4 digital inputs that could be expanded using a logic encoder (after conditioning the aircon voltage 24 V -> 5 V).

Another musing / thought is to use a four bit D/A (digital to analog) converter and leverage analog voltage 0-5 Vdc measured by Botz. This would allow you to delineate four different digital inputs. Incomplete table below illustrating the for inputs and voltage output (to feed into Botz).

DCIM_Support · ‎2020-07-05

This comment was originally posted on DCIM Support by nanoman on 2018-11-20

If you wanted to use the 0-5 Vdc input to monitor multiple inputs, you could use a 8-bit D-to-A module like

http://www.industrologic.com/updac8man.htm

and just use the upper 4 or 6 bits (each one connected to an reduced voltage aircon output). I don't think the resolution and stability would support all 8 bits (inputs). 8 bits would be 5 vdc/128 or 0.039 vdc.

This is not an elegant solution and would you have to use a look up table based on voltage to determine which input(s) is off. The voltage threshold alarm would only indicate that at least one of the inputs is down. The actual voltage level would allow you to determine the status of all (4 or 6) inputs.

DCIM_Support · ‎2020-07-05

This comment was originally posted on DCIM Support by Alex Rente on 2018-11-27

Hey nanoman,

thanks a lot for your effort and sorry for the late response. Could I ask you what is your technical qualification?

To the questions...

Round about 16 DI´s
They have all on/off states with 24V or 0V
I think, it would be better, if the netbotz is able to notify exactly the current states

The NetBotz is global standard at our company, so I am not sure if can use other devices, respectively we want to replace the current solution with Netbotz (Only?!).

But your solutions are also very helpful and I will consider them and give a feedback 😃

Does Netbotz got those extending option...? or is an external device mandatory?

DCIM_Support · ‎2020-07-05

This comment was originally posted on DCIM Support by nanoman on 2018-11-28

Hi.

I have no per se technical qualifications. I have used Botz for years to monitor various equipment in my barn. I have five botz (355, 420, 320E, 400, 100 (blue unit ~20 years old)) . Most are connected to sensors or custom electronics to monitor things like electrical power (on or loss), boiler pressure and temperature, barn door, motion sensor, etc.

DCIM_Support · ‎2020-07-05

This answer was originally posted on DCIM Support by Alex Rente on 2018-12-11

Hello,

I just got this open question:

I would need a lot more 0-5V inputs. Is there a possibility to extend those with intern solutions?

Otherwise there is no other way than buying a another Netbotz or use the good suggestions from nanoman...

DCIM_Support · ‎2020-07-05

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