PLC Testing

Connect to our PLCs via VPN

PLC program without errors maximise safety and system reliability.


We program diverse types of PLCs: different brands and models. Most of them are latest series from Allen Bradley, Schneider and Siemens. Applications are different too. Some applications have just tens of IOs with complicated logic which includes lots of PID loops. When others have a simple logic with hundreds of IOs. High number of IOs indicates that a high number of alarm rungs have to be developed. During the logic development you have to copy and paste lots of timers, similar looking rungs and, perhaps, UDTs/FBs (User Defined Data Types / Function Blocks). During the copying there is always a possibility to miss to change a timer's number to the next one. Or a latching bit is the same as in the previous rung. It happens a lot, with a graduate or highly experienced engineers.

There is only one way in assuring your PLC program is error free. It is testing with a real PLC. When you want to ship your work "polished" you have to have a PLC near your computer for live testing. But it is not always available, due to either costs, diversity of the projects or remote work.

To be able to test PLC program anytime we have been using VPN to connect to our PLCs. We set a number of common PLCs in our workshop. Every PLC has its own ethernet connection to a specially configured VPN router.

We use it for logic testing of our PLC programs. We simulate IOs with Node-RED function blocks. We create a complex testing environment to provide high integrity and reliability of developed PLC programs.

Book a PLC below for testing and make sure the program is error free.

Who IS this for

For both an experienced controls engineer or for a beginner.

If you are an experienced engineer and already have a PLC at your desk you can create a PLC network for serious communication tests. Or you can use Node-RED in combination with Siemens S7 communication node or Allen Bradley CIP comms node to create a complex testing environment to simulate field equipment connected to local IOs. Also some SCADA testing will require a few PLCs at the same time.

If you are a beginner you can practice your skills on the high grade PLCs without buying an expensive hardware. There are great PLC online courses where you can receive high quality theoretical lessons and practice it on our PLCs. See just a few links to the great PLC courses: Allen Bradley PLC Training - RSLogix 5000 Series (Shane Welcher's youtube channel) and RealPars on Siemens S7 (RealPars’s youtube channel).

Also PLC courses is apart of electrical engineering. If you are taking Systems and Control (eg. ELECPS8338), Controls Engineering (eg. MEE30002) or TAFE Programmable Logic Controllers - Basic (eg. 357-24059V01) courses, you can learn quicker by practicing your knowledge on real PLC.


It is a simple process, there are just 3 steps:

    • Fill in the reservation form below
    • Download VPN Client
    • Connect VPN Client to selected PLC

It will create a VPN network between your PC and the PLC.


Currently we have a number of Allen Bradley and Siemens PLCs set and ready to go. Some could be booked out by other users. We are bringing more brands and models of PLCs to our network.

Please contact us for either to confirm availability, enquiry on a specific PLCs or cost of usage. Prices start from $2 per hour (for Siemens LOGO!). First 4 hours are free!

Available PLC Model

- Siemens S7-1200
- CompactLogix 5332E
- ControlLogix 5561
- ControlLogix 5574
- MicroLogix 1400

Complete a reservation form to secure your time slot.


Q1: When trying to connect I'm getting an access error. Error Code 12: Access has been denied.

A1: This indicates that the VPN Client can connect to the server but the user has no permission to connect to this PLC hub. Possible reasons:

  • user’s time slot has expired or hasn’t started yet
  • trying connecting to wrong Virtual Hub Name

Solution: check the details (date, time and Virtual Hub Name) with confirmation email from us.

Q2: Do you provide a support on the PLC programming?

A2: We will help with establishing a connection to our PLCs. PLC programming consultation is out of free service, however we always can arrange a good deal.

Q3: How different is this from RS Emulator (or PLCSIM)?

A3: The emulator is a great tool, however it has a number of limitations: scan time is always slower (don’t know why), impossible to simulate communications between PLCs and there is no way to programmatically simulate IOs. The last one is a big one for us. With real PLCs via VPN we use Node-RED and Siemens S7 communication node or Allen Bradley CIP comms node to simulate field IOs. For example, to simulate an operation of limit switch at digital input 1 when a motor contactor is closed, we do the following: on output 1 it waits for 5 seconds and sending signal to input 1.


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