00:03
Sensing temperature is one of the most common and easiest applications in a
00:07
control system. Here we are in an IT server room and like most server rooms
00:12
no one really comes in here all that often. So what happens if the
00:16
air-conditioning fails? You really only find out about it when servers start to
00:21
overheat and fail. Even if we don't control the room temperature it sure
00:26
would be nice to monitor it. Well in this video workshop we'll show you how easy
00:30
it is to sense the room temperature and move that data into a software
00:35
application. So let's head back to the workshop and get started.
00:43
Here we are back in the workshop. Before we start hooking things up let's start
00:48
with the big picture. What's the signal path from a high level? Well here's a
00:53
block diagram of what we're going to do. We're going to take a temperature sensor
00:57
which is an electrical signal and we're going to convert that to digital data
01:02
suitable for use in any number of software or cloud applications. Now for
01:07
this workshop I'll be using this SNAP PAC Learning Center it's basically a SNAP
01:12
PAC system with a controller, several i/o modules, and a rack. We use it for
01:18
training here at Opto 22. This panel simulates some typical i/o signals like
01:24
a meter, potentiometer, temperature sensor, LEDs, and switches. The controller is
01:31
running a control strategy that's loaded into its memory and I'll be using PAC
01:36
Control on this Windows laptop to configure the strategy and then download
01:41
it to the controller. You can get your own Learning Center and free PAC Control
01:45
software at workshops.22.com. Now arguably one of the easiest ways to
01:53
sense temperature is with an integrated circuit temperature device or ICTD.
02:00
ICTDs excel and applications that require fairly accurate readings from -40
02:06
to +100 Celsius which is perfect for our server room temperature. The ICTD
02:12
sensor outputs a micro amp signal that's proportional to its temperature. Who
02:18
cares - why is this important? Well what it means is that you can get an accurate
02:22
temperature reading up to 600 meters away. So you might be able to use some
02:27
dark cat5 cable that you've already got running through your building to pick up
02:31
several temperature sensors from different locations. The temperature
02:35
input modules come in 2, 4, or 8 channel and they can work with different types of
02:41
temperature sensors like this ICTD thermo-well sensor. ok now when it comes
02:48
time to actually hook things up you'll find the wiring diagram on the side of
02:52
the module and the wiring on this one is actually pretty hard to get wrong.
02:56
There's only two wires so for this two channel SNAP- AICTD module simply
03:02
connect the white wire to Terminal one
03:08
and the black wire to Terminal four. Now I'm going to add the temperature module
03:24
to the i/o rack by snapping it into place. I'm going to put it in position
03:29
seven here on the end. So that's the wiring and the module installed. So now
03:36
let's go to the laptop now and configure the software. Here we are in PAC Control
03:41
and we've already got our rack configured. So now let's double-click on
03:44
the empty slot in position seven and we're going to add an analog input
03:50
temperature module. In this case it's a SNAP-AICTD. We're going to double click
03:58
on the first one on the module to open the point configuration dialog. Now we'll
04:05
give the temperature sensor a tag name like "server room temp". Now this is where
04:11
the temperature sensor is given a meaningful name for your software
04:15
application or cloud services. So make sure you choose your name accordingly.
04:22
Now click on the debug button to download the configuration on your
04:26
controller. Click yes to save and yes that you've made a change and the
04:33
download process will start. Once it's done click run to execute the new
04:37
strategy.Let's open up the debug window by double clicking on the point and we
04:45
can confirm that we've configured our ICTD sensor correctly by viewing the
04:50
temperature in real time right here. Now at this point we can use PAC Control to
04:56
monitor the temperature value and sound an alarm if it goes out of limits or we
05:01
could just log the temperature in the controller. Using a tool like NODE-Red we
05:06
could write that value to a database either locally or in the
05:10
cloud or we could send it to any number of cloud services like IBM Watson or
05:15
Microsoft Azure. For more information about temperature sensing check out our
05:20
primer on i/o solutions for temperature monitoring. It's form number 1767 on our
05:26
website. But you can also find a link to it on workshops.opto22.com and there
05:32
you'll also find a list of the parts that I used for this workshop. So there
05:37
you go the electrical signal from the
05:39
temperature sensor has been converted to digital data. Cheers mate!