We need a remote display for our field operators to monitor our milk temperature. We already have a temperature transmitter there, but it doesn't have a remote display. Rather than change it, we'd like to add a remote display. Could you help us with a good solution?
Expert’s answer:Remote display for milk temperature on a tank
Of course we can! You definitely need temperature measurement on a milk tank to ensure the quality of your product. And you’ll need your sensor to verify that milk temperature constantly and accurately.
But you’re right when you said you don’t need to replace your transmitter to get a remote display. You didn’t mention the output of your field device, but let’s go with analog/HART, as that’s pretty popular in this type of process.
You can find a bunch of universal displays on the market to fit this scenario. I’ll give you some options I found with some technical details, plus a list of other possibilities.
How do I install a display in my loop?
If you have an analog device, then you can install a display to read the analog signal as a current meter, and some of them can translate the signal to the measurement range. Now, if you have HART, then some displays can work as master 1 or 2, reading the HART variables and showing them to the operator.
Even if you’re using digital communication, you can still find local displays to read your milk temperature. You’ll have a smaller range of options than you would with analog, but you can find some good choices.
I found a few random examples on the internet, with simple descriptions of their features:
This universal display from IFM can receive two analog inputs, such as 0-20 mA, 4-20 mA, and -10-10 volts. The DX2041 can power up with alternating current (115-230 AC) or direct (18-30 DC). Its compact size makes it easy to find a spot to install it. Of course, you can find more options from IFM if you need a display with more features.
RIA 15 – Endress+Hauser
The RIA 15 is a loop-powered display from Endress+Hauser. Here, you don’t need an external power supply, as the loop can power it up. But check the specs before installing it because it has minimum requirements.
Beyond that, the display has a single input, where you can read analog or HART. Moreover, you can install it on a panel or buy it with a field housing.
N1540 – Novus
The N1540 from Novus can connect to various thermocouples, Pt 100, and analog devices with voltage and current output. It powers up with 100 -240 AC/DC volts, but you have options for 12 to 24 VAC/DC and RS485 Modbus RTU serial communication. It has lots of features that you can read about here.
One of these devices should help your operators read the milk temperature on your tank remotely. If you have any other questions, then we’re always ready to answer!