I recently had to put a PLC/HMI combination together on a tight budget. I was familiar with the AutomationDirect.com (Koyo) DL06 and find it to be a good small PLC. The base unit has 36 I/O (20 inputs and 16 outputs) and comes standard with four (4) expansion slots and two (2) communication ports. See the DL06 HERE. The expansion slot options include a 4-Channel Analog Input module (0-20mA and 4-20mA), a 4-Channel Thermocouple Input Module, a 4-Channel RTD Input Module, and a host of communications modules.

I had not yet had the opportunity to mate a DL06 with an HMI; however, when a project came along which required an HMI with my DL06 PLC, I took a chance and implemented a C-More Micro Graphic user interface. See the C-More Micro Graphic products HERE. I was pleased to find that AutomationDirect offered a 6", 5-color, touchscreen for just $299 - AND the software was FREE. I downloaded the software and was surprised to find that it was amazingly intuitive. I created a project and was impressed to discover that the manner in which the graphics and text appear in the development software was a true representation of how the graphics and text will appear on the panel once downloaded. The software offers everything a programmer will require: Numerical entry/display objects, multi-state indicators, and dynamic text objects. The alarm annunciation resources for this HMI are a bit weak; however, for the price I paid for this software, I have no complaints.

The application which I had to utilize this PLC/HMI combination was for a natural gas application (Class 1, Div. 2, Grps. ABCD). I used an Akron Electric NEMA 7, Explosion Proof enclosure with a window to house my controls. I used thru-panel, NEMA 7 pushbuttons to allow the user to interface with the HMI. Surprisingly, the C-More Micro allows the user to select a register in the target PLC to control the screen selection. I used a simple increment/decrement function off one of the NEMA 7 pushbuttons so that the user could select screens. I used six (6) NEMA 7 pushbuttons: One (1) for dedicated screen navigation, and five (5) for ancillary functions which varied from screen to screen.

This project was a home run. When I told my salesman that I put together a PLC/HMI combination for this hazardous location, natural gas application for less than $600, he couldn't believe it. If you're looking for a low-cost, powerful, dumb terminal and/or a low-cost powerful PLC, I highly recommend the DL06 and the C-More Micro available from AutomationDirect.com. One additional advantage with using the DL06 with the C-More Micro is that as mentioned above, the DL06 has two (2) serial communication ports. You can utilize one of these ports as the programming interface and use the other to communicate with your HMI. Very smart designs and low cost make the AutomationDirect (Koyo) products a viable option for any serious integrator.