FactoryTalk View HMI Programming

[W.W. 1]

As a disclaimer: I'm fairly new to HMI programming and I haven't been using FT View Studio for very long. I'm developing an HMI for an AB PV+ 700 that talks to a MicroLogix 1200. I have a series of buttons in an HMI display and an integrated control stepper motor that is being controlled by the MicroLogix. There are a bunch of preset positions of the stepper motor linked to the buttons in the HMI but I want to be able to add new positions of the stepper motor to empty buttons in the HMI. How might I go about doing that? Can I set tags on the buttons to store the data being read at a certain memory address? (I'm not sure if that's the correct wording for that) As a side note: is there any way to manually code an HMI for a PV+ in a language like C or Python (or even VB)? Edited 14 Dec 2010 by W.W.

[PMersault 1]

No "manual" way to program, and on the PV+ side (as opposed to the distributed SCADA side) no VBA scripting available either. I can't think of a way to push values into empty buttons from the controller, but would a numeric input work? This would allow you to enter/display the value directly, then use a button if you want to force the operator to "accept" the value (i.e., write the value down to a tag in the controller, then use the button to toggle a bit high on the rung moving the tag value to the motor.)

[JRoss 84]

Program it to work like the presets on a car radio. Make the HMI buttons trigger a bit in the PLC. Each bit should have a correlary data register that stores that button's preset. If the button is pressed and held (put a timer on the bit), then move the current stepper position into the data register for that button. If the button is pressed and released, then move the position in the data register to the command position for the stepper.

[W.W. 1]

Thanks for the tip JRoss. I understand the idea conceptually. Could you please expand on the data register portion of it? Is it somewhere in the ladder logic that I set it up and then just read from and write to it? (I'm using RSLogix 500 if that matters) I think understand how to do everything else except for storing the position in the data register.

[JRoss 84]

I can't really answer that without knowing a lot more about your system. Steppers and stepper drives come in a lot of flavors, so you'll have to figure out how the control is handled. For example, I did a system one time using a Mitsubishi FX1N (similar to the Micrologix 1200) controlling a stepper motor. For this system, I drove the stepper to position using a pulse-train output. If I wanted the stepper to move 1000 steps, I would output 1000 pulses. The FX1N has absolute commands that can be used with the pulse output, so I could put a position (in steps) in my absolute command and the stepper would go there. The FX1N also has a special data register that tracks the number and direction of pulse output, and returns the current position of the stepper (assuming that the stepper actually followed the command. You'll have to look into the current code interface between your stepper and the Micrologix to see how this works. Look in the HMI program to see what bit address one of your current preset buttons is connected to (look in properties, connections). Then find that bit in the PLC program, and see what it does. Somehow the bits are telling the stepper where to go, and you can tie into that. As far as feedback, I haven't used the Micrologix for this type of application, so it may not have a special register like the FX1N.

[Michael Lloyd 85]

I might be missing something but if there are already buttons performing the function that you want to make happen in empty buttons why not dig into the existing working buttons and duplicate what they are doing?

[michael G 2]

I use JRoss's Method but I split it across two screens - I prefer to have setup separate from operation. One screen with the Goto Buttons Each button displays a Position and has a visible attribute from the PLC (enable / disable) The Setup screen has the buttons in the same location as the goto screen with axis inch Fwd / Rev buttons as well. Pressing the buttons on the Setup screen toggles between disabling the button or capturing the current location for the button setting