For applications that require precise temperature measurement, you'll find that an RTD is often prescribed by the experts. The resistance of the element inside an RTD will change with temperature, and because it's made of a pure metal (usually platinum), this resistance value will change in a precise and repeatable way. The RTD Phidget measures these subtle changes, so you can get the most accurate temperature measurements sent right to your VINT hub. See the Comaptible Products tab for a list of VINT Hubs.
Setup is easy with this adapter; you can choose the number of wires that your RTD has (2, 3, or 4), and then select the type of RTD you're using (PT100, PT1000, etc.) with commands in our API. The adapter does all the math, leaving you with the sampled temperature in degrees Celsius.
You can also read thermistors and other resistive sensors by using the resistance sensor object in your program. You'll receive the data in ohms, and can convert to the desired unit by using the formula in your sensor's datasheet. You could even use it as a simple ohmmeter for resistances up to 19 kΩ.
This Phidget is a smart device that must be controlled by a VINT Hub. For more information about VINT, have a look at the VINT Primer. You can use a Phidget Cable to simply and easily connect the two devices. Here's a list of all of the different VINT Hubs currently available:
Here's a list of RTDs you can use with the TMP1200:
Use a Phidget cable to connect this device to the hub. You can solder multiple cables together in order to make even longer Phidget cables, but you should be aware of the effects of having long wires in your system.
Welcome to the TMP1200 user guide! In order to get started, make sure you have the following hardware on hand:
Next, you will need to connect the pieces:
In order to demonstrate the functionality of the TMP1200, the Phidget Control Panel running on a Windows machine will be used.
The Phidget Control Panel is available for use on both macOS and Windows machines.
To open the Phidget Control Panel on Windows, find the icon in the taskbar. If it is not there, open up the start menu and search for Phidget Control Panel
To open the Phidget Control Panel on macOS, open Finder and navigate to the Phidget Control Panel in the Applications list. Double click on the icon to bring up the Phidget Control Panel.
For more information, take a look at the getting started guide for your operating system:
Linux users can follow the getting started with Linux guide and continue reading here for more information about the TMP1200.
After plugging the TMP1200 into your computer and opening the Phidget Control Panel, you will see something like this:
The Phidget Control Panel will list all connected Phidgets and associated objects, as well as the following information:
The Phidget Control Panel can also be used to test your device. Double-clicking on an object will open an example.
When you double click on an Resistance Input object, a window like the one pictured will open.
When you double click on an RTD Input object, a window like the one pictured will open.
Before you can access the device in your own code, and from our examples, you'll need to take note of the addressing parameters for your Phidget. These will indicate how the Phidget is physically connected to your application. For simplicity, these parameters can be found by clicking the button at the top of the Control Panel example for that Phidget.
In the Addressing Information window, the section above the line displays information you will need to connect to your Phidget from any application. In particular, note the Channel Class field as this will be the API you will need to use with your Phidget, and the type of example you should use to get started with it. The section below the line provides information about the network the Phidget is connected on if it is attached remotely. Keep track of these parameters moving forward, as you will need them once you start running our examples or your own code.
You are now ready to start writing your own code for the device. The best way to do that is to start from our examples:
Once you have your example, you will need to follow the instructions on the page for your programming language to get it running. To find these instructions, select your programming language from the Software Overview page.
This is the simplest wiring setup for an RTD, but also the least accurate because the resistance of the leads are not taken into account. To connect a 2-wire RTD to the RTD Phidget, connect one wire to the RTD+ terminal, and the other to the RTD- terminal. Then connect the EXC+ terminal to the RTD+ terminal and the EXC- to the RTD- terminal with two short wires.
In your program, set
RTDWireSetup to 2-wire mode. In the Phidget22 API select the TMP1200 and your programming language of choice to see exact naming conventions.
In a three-wire RTD, the extra wire is added to measure the resistance of one of the leads. This calculation assumes that both leads have the same resistance. Your RTD should have two wires that share a color; connect one of these wires to the RTD- terminal and the other to the EXC- terminal. The differently colored wire connects to the RTD+ terminal. Then connect the EXC+ terminal to the RTD+ terminal with a short wire.
In your program, set
RTDWireSetup to 3-wire mode. In the Phidget22 API select the TMP1200 and your programming language of choice to see exact naming conventions.
A four-wire RTD is normally used in precision measurement, when the assumption that both leads have the same resistance is not accurate enough. Unfortunately the RTD Phidget does not support this particular feature of four-wire RTDs. It does, however, support the use of four-wire RTDs using the same assumption as three-wire mode. To connect a four-wire RTD, simply connect one pair of same-colored wires to the RTD+ and EXC+ terminals, and the other pair to the RTD- and EXC- terminals.
In your program, set
RTDWireSetup to 4-wire mode. In the Phidget22 API select the TMP1200 and your programming language of choice to see exact naming conventions.
In three and four wire modes, this device will measure the line resistance every 5 minutes. This measurement will cause a delay in measurement for data intervals of less than 500ms. To force the line resistance to be recalculated, you must close and re-open the device.
The amount of current consumed by the TMP1200 depends on the DataInterval being used:
|Maximum Measurable Resistance||50 kΩ|
|Temperature Error Max||0.2 °C|
|RTD Current Max||62 μA|
|Sampling Interval Min||250 ms/sample|
|Sampling Interval Max||60 s/sample|
|Current Consumption Min||17 μA|
|Current Consumption Max||4 mA|
|Recommended Wire Size||16 - 26 AWG|
|Operating Temperature Min||-40 °C|
|Operating Temperature Max||85 °C|
|TemperatureSensor||Visual Basic .NET||Windows||Download|
|ResistanceInput||Visual Basic .NET||Windows||Download|
|Date||Board Revision||Device Version||Comment|
|August 2017||0||104||Product Release|
|January 2018||0||105||Increased maximum change trigger|
|January 2018||0||106||Library bug fixes|