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A Simple, Inexpensive, & Quick Solution Saves the Day! We recently were asked to solve an unexpected issue for one of our PLC customers. They use the high-performance Mitsubishi Electric iQ−F PLC, also known as the FX5U, which is equipped with 2 Analog Inputs and 1 Analog Output. The Analog Inputs are rated for 0 to 10 Volts with a 12-bit Analog to Digital converter allowing for a resolution of 2.5 mVolts. The digital number seen in the PLC will range from 0 to 4000. The Analog to Digital converter has a very fast conversion speed of 30 microseconds per channel, ensuring an updated Analog Input reading every PLC scan. These Analog Inputs are easily used for many applications, such as Potentiometers, Level Meters, Light Meters, Height Sensors, etc. If your device outputs 0 to 10 Volts, you can connect it to the off-the-shelf iQ−F PLC. Well, this is where the problem came in. They had already purchased a laser height sensor for their project, but it was not until they added it to their machine that they realized they had ordered the wrong sensor, one with a 4-20 mA output which their iQ-F PLC could not read. They were in a real bind because they had to get the line running as soon as possible, as in minutes, not days or weeks. Had they ordered the iQ-F PLC with the FX5−4AD−ADP module, they could have used either voltage, or current inputs, but that is not what they were using. The “5-cent solution” we recommended, quickly saved the day. By adding a simple 250Ω resistor (¼ watt, 5% tolerance) across the Analog Input terminals, we instantly converted the Voltage Input to a Current Input! This is the normal wiring for a 0 to 10 Volt Analog Input… And this is what the wiring looks like after adding the resistor… This resistor converted the 4 to 20 mA signal into a digital value of 0 to 2000 in the PLC. Now our customer was able to use their Current type of Analog device. And that is all there is to it!
The Mitsubishi Electric iQ-F PLC comes with Ethernet built in. One of the many things this Ethernet port may be used for is a Web Portal. This Web Portal gives the user access to important data in the PLC by simply using a standard Web Browser. Things like serial number, firmware version, errors, and diagnostic information are easily accessed. A user can also check actual data running in their PLC program. Not only can they read the data, but if they log in with the right permissions, they can change the data as well! Imagine small OEM machines that may not come standard with an HMI. Things can easily be configured and setup in the machine by simply using a smart phone or tablet. A simple WiFi access point on their network would allow them to easily access the data on the iQ-F Web Portal. The Web Portal has a few pre-defined screens. However, if the user wants to implement something more unique or specific, they can do so by using html to create their own custom screens. Simply adding an SD Card to the iQ-F PLC would allow the user to store countless html screens. Here is an example of a built in screen: And here is an example of a user developed screen: This is a very powerful feature that comes standard in the iQ-F (FX-5U) PLC! Easy to implement and a great way to communicate with your machine, especially if your machine does not have an HMI on it. Check out the Web Portal on your Mitsubishi Electric PLC today! Methods of Networking to Connect to iQ-F Web Server Access to PLC Web Server WiFi Access directly to PLC Web Server Remote Access to PLC Web Server
Recently we had a request from a customer who wanted to expand and improve his CNC tending operation. For more than a year the plant had been using a UR10e collaborative robot from Universal Robots to load and unload parts from one of his CNC machines. He was very pleased with the initial ROI on the project, and with the ongoing value of that installation that he decided to implement the UR Cobot on a second CNC machine. The idea was to use a single Universal Robot to simultaneously tend both CNC machines. Unfortunately, the second machine was out of the cobots reach. Together with HTE's TECHTEAM a low-cost solution was developed that added a horizontal seventh axis to the cobot. This additional axis would move the robot between the two CNC machines as needed. A simple extrusion frame with some slider rails was used, and a mount for the robot was made to slide back and forth on these rails. A stepper motor was used to drive a belt to move the robot mount, all of which was pretty straight forward. You can see the application in action in this brief video. The question remaining though was how to drive the stepper motor? The initial installation included an HTE specified Mitsubishi iQ-F PLC to control hand shaking with the robot and the CNC. The iQ-F PLC has highly functional positioning control built right in! This made setting up the stepper motor control very simple. Simple tables to setup the parameters are included which allow for up to four axis of positioning control. HTE's TECHTEAM was able to specify the optimal units of measurement, the number of pulses of resolution the stepper motor had, and also to define the gearing ratio of the belt drive. On this application, we only had 3 positions we wanted the robot to go to. To make things even easier, we used the built in Position Tables to pre-define these 3 positions. Now the PLC program is about as simple as it gets! We just tell it which of the 3 table entries to use, and the iQ-F takes care of everything else for us. Very simple! Here is what the Axis setup looks like: Here is what the Position Table looks like: It does not get much easier than that! With these configuration tables we were able to use two of the Transistor outputs on the iQ-F PLC to drive the Stepper Motor. These could also be used to drive a servo if required. No need to count Stepper pulses in your PLC program! No need to figure out if you should turn on the direction changing output or not! Just pick a Table number and tell it to go! This was a great low cost solution that was easy to implement and allowed our customer to get even more out of his existing Universal Robot. Regarding positioning, the FX5U comes with the built-in capacity for 200kHz high speed inputs and outputs. This provides the capability to control up to 4 axes of positioning with stepper or servo motors. The FX5U is a cost effective solution for: interrupt operation, multistage speed operation, simple linear interpolation, and simultaneous start of 2 axes.
I recently worked with a customer asking for help with upgrading the performance of their feeding machine. The machine indexes material into another machine upon demand, using a simple I/O handshake to feed in material when the processing machine requests it. Their prior designs have used VFDs and even stepper motors. While these low-cost machines did the job, they were unable to keep up with the marketplace’s demand for ever higher accuracy and speed. Our TECHTEAM felt that switching to a servo motor-based system was the logical choice for delivering the enhanced performance requirements because with a servo motor, users can achieve the rapid accelerations and decelerations they required. Additionally, the servo motor system allows for much faster feeding, which also quickens cycle times. Adding to each of these speed improvements, a servo motor allows for the precise feeding of an exact amount of material. Because of their initial concerns about both the servo’s expected cost, and implementation complexity, they were reluctant to make the switch to servo motors, concerns our team was quickly able to put to rest. Enter the Mitsubishi MR-JET high-performance, low-cost servo! The MR-JET is the newest, and lowest cost member of Mitsubishi Electric’s extensive servo family, and yet it retains all the precision control for which Mitsubishi Electric is known. But what about ease of implementation? Our team chose to pair the MR-JET servo with Mitsubishi’s low-cost iQ-F PLC which accommodates all the feeder machine’s I/O and control logic requirements, and which is capable of controlling multiple servos using it’s integral Ethernet. Because no Ethernet switch is required, we simply ran an Ethernet cable from the iQ-F directly to the MR-JET Servo drive. If needed, we could simply daisy chain the Ethernet to another Servo using the 2nd on-board Ethernet port. In this case however, we used the second Ethernet port to connect to a Mitsubishi GOT HMI. Programming was very simple to setup using GX-WORKS3 which uses a simple drag and drop utility to add the servo to the program. Programming the motion in the PLC was as simple as dragging standard IEC-61131 function blocks into the ladder program. So, just like that, our customer ended up with a low-cost, high-performance servo system that is simple to program, simple to troubleshoot, and easy to wire! This is a sample of the PLC program using simple function blocks for an Incremental move to control the product feed: