Jump to content

Thrown into the deep end :)

Recommended Posts


Just a brief background to myself; I've been an on/off programmer for more than 20 years but now focusing on general IT support. I've been asked by one of my clients to get involved in creating automation systems for one of their ventures. Currently a previous employee at this company had implemented UniLogic products into the general network which I though was best to kept and standardize on.

My question is though; we have a project to move high pressure water from 4 kms below ground to the surface, while detecting levels of methane within that water. Now I'm a complete novice with PLC's in general I'm hoping somebody could give me a high-level insight to what would be required to get this project to completion. My basic understanding is that the UniLogics UniStream (PLC+HMI built in) would accept data from a methane detector and process that data, accordingly, i.e. push it to a data collection server etc. The Unilogic device would also have the ability to send commands to a water valve to either open or close either by human interaction via the HMI or code being evaluated within the PLC project that is pushed to it. 

Where my knowledge gets a little hazy is how the PLC+HMI and these 3rd party devices are connected? Do I need to be looking for 3rd party devices, i.e. methane detector, that have RJ45 Modbus connectors? Sadly, I don't a have UniLogics controller to play with so I'm resorting having to go through YouTube and other online material and it's a serious mountain to climb :)

So, I'm hoping somebody would be patient enough to give me a guiding hand.






Link to comment
Share on other sites


Methane detectors and Unitronics PLC.

Unitronics   PLC's  support Modbus Protocol by default - it is built in.

Most smart devives will also have Modbus Protocol support built in.

Let  Modbus be your friend - Look for a Methane device that supports Modbus Protocol, and have either a RS485  or Ethernet Ports -  and let them communcatethe data between them.

The Device  manual should contanl all the relavent information about the Modbus registers to use  to exchange the data.

The Unitronics PLC - Vision  or better  Unistream   can be set up to poll the Methane device  regularly for the data.

Download the software and example program files and look at the sample programs - Communications - Modbus   as a guide.





Link to comment
Share on other sites

  • MVP 2023

DanT has provided some excellent help. I will add that you need to get some of the terminology correct so that your searches will be more accurate:

UniStream - the PLC hardware (PLC+HMI device), there are various models of the UniStream PLCs

UniLogic - the programming software for the UniStream hardware

Unitronics - the manufacturer of the hardware and programming software

7 hours ago, Chris Edwards said:

Sadly, I don't a have UniLogics controller to play with so I'm resorting having to go through YouTube and other online material and it's a serious mountain to climb :)

I strongly recommend that you purchase the hardware you will be programming as soon as you possibly can. There are no logic simulators and your project development will require that you experiment and test as you go along.

  • Like 1
Link to comment
Share on other sites

  • MVP 2023

That depends.  There is a "Modular" unit where you add all the I/O modules and then there's a unit with some onboard I/O called a "Built-In".


The Modular unit is a front panel with a separate CPU module.  It's the original UniStream type and has all the features.  The Built-In has varying levels of bells and whistles to get the price down to appeal to the OEM market.  If you go with the Built-In, get the -B10 option which has all the stuff.

Reach out to Unitronics to figure out who sells their product in your part of the world.  Here in SeppoLand,  a 7" unit goes for $1,500 - $2,000 US.


Joe T.

  • Like 1
Link to comment
Share on other sites

17 hours ago, Chris Edwards said:

Can somebody give me a rough idea of what a UniStream 7" PLC+HMI cost?

You have three hardware variants with Unitronics UniStream product line:

1. Classical approach: UniStream variant where PLC is a completely separate device from the HMI touch panel, and it does not require a Unitronics-branded panel to operate. Most PLC equipment manufacturers like Allen-Bradley, Siemens, B&R or Beckhoff make PLCs like this, that's why I call it the "classical approach". For visualization, you can connect any VNC-capable device to the PLC and it'll show the screen, because the screens are rendered and processed inside the PLC, not on the HMI. Example: USC-B10-TA30, which is a flagship Unitronics PLC. It costs around $900 here in Serbia. A low-end PLC would be for example USC-B5-T24, going for about $500. You can hook it up to any HMI panel of your choice (VNC or raw fieldbus), or make visualization on a desktop PC, laptop, or a Android tablet. I would of course prefer a Unitronics HMI panel, and you can go for a USL-070-B05, which is a 7" resistive touch screen going for about $450 here. In total it would get to around $950.

2. Modular PLC and HMI: this is the original UniStream solution where the panel is executing and rendering the HMI graphics, while a dedicated CPU module attached to the HMI is taking care of program scan and communications. In this variant you must go for a Unitronics HMI and CPU module. Backside of modular panel has a plastic DIN rain onto which you can attach the CPU and additional modules, even your own components like 24V PSU or relays. Good thing about this variant is that you can add as many additional I/O modules that you need, and the bad thing is that the CPU module doesn't have any I/O onboard, so you must shop for I/O modules: digital and analog inputs, outputs, even serial ports. For this variant I'd go for USP-070-B10 panel (7" - $800) and USC-P-B10 (Panel CPU - $350), in total around $1150. You can add and I/O modules you need depending on the project.

3. Built-in PLC/HMI: this is the newest UniStream variant, which is similar to Modular approach, only the CPU and I/Os are integrated into the HMI panel. So instead of shopping for panel, CPU, and I/O modules, you get one device which has everything inside. This is great if your available panel space is tight, or you're building 10+ identical machines. Only downside is that I/Os are located on the HMI panel itself, so you'll be running plenty of wires from the panel doors onto the back panel. For this variant, let's go for US7-B10-TA30 (7" flagship built-in)  which goes for around $1250 here.

Of course take these prices with a grain of salt. My tax structure here in the Balkans may be different, and your local Unitronics dealer will probably give you more accurate price.

Good hunting!

  • Like 1
Link to comment
Share on other sites

  • MVP 2014

Hi Chris,

I'll comment here to start with. I work for Colterlec who are the Australian distributor for Unitronics.  The advice above is great, as always.

I agree, use Modbus for the Methane instrument.

I have asked our customer service team to quote you for the Modular option and the Built-In option. We can also assist with the Classical option if needed. Since it sounds like you are working with an existing design, let me know what items that is using.

I'll contact you via email also.

Feel free to continue searching for answers here and asking application questions, However if you need commercial details or urgent answers please contact us directly.

Kind Regards, 



  • Like 1
Link to comment
Share on other sites

Hello Chris!   .......... Welcome!     :  )

Could you elaborate a bit more on your project? 

..... is this deep bore hole extraction? ....... fracking stuff?

I have no "hands-on" experience in deep well water/gas extraction  ....... but that never stopped me!     :  )

I'd love to help in your design quest!


........ need you first separate the gas from the water (centrifuge) before you determine the methane's concentration level?

Gas Water Centrifuge.jpg



............ or if you need to sample while in the water: 

Cavity Ring-Down Spectroscopy (CRDS)


  • Drift-free measurement
  • Increased laboratory safety without the need for fuel gas
  • Self-tuning and auto-calibration
  • Extremely low Cost of Ownership
  • Ethernet, 4–20 mA and RS-232 connectivity
  • Fast response with low gas consumption
  • CH4 analysis over a vast range: 7 ppb to 50 ppm (in O2)


Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...