Joe Tauser

If you use the Modbus function blocks you won't have to worry about formatting the data packets or checksum as you describe. The block does that for you. There are Modbus examples that are a good starting point. You will have to do your own handling of the commands to each drive, writing a program that will trigger read and write blocks individually and not crashing into other blocks while they're busy. Start by connecting one drive and getting a feel for how the Read and Write blocks work, and then adding the other drives and sequencing between blocks for those. Don't forget that Unitronics is 0 based and Modbus is 1 based. If you're not getting the right data, try subtracting 1 from your start address. Post your code as you go along if you run into problems. Joe T.

Emil - 10 years ago we were running Windows 98 on color CRT's. Don't tell me your memory has gotten as bad as mine! Unfortunately, I have recently acquired a lot of experience running multiple monitors with Windows on a project. We have a LabView app that is supposed to put separate windows on three separate monitors. Trying to get it working right has been a nightmare. The picture on the front of the video card box makes it look so easy! First of all, XP does not have multi-monitor management built into the O/S. It's dependent on the utility that comes with the video card. Windows 7 does have multi-monitor management built in, but as of now you can not select which monitor is 1 and which is 2 (or 3). You are allowed to select which one is your primary workspace, which contains the taskbar. The monitor designed as 1 will be the first one the computer sees when it boots, and it will remember this for next time. Unfortunately, if that monitor isn't powered up when the computer boots, it will look for another and assign it #1, and remember it until you go back and disconnect it, power up the other one, and then reboot the computer. Another problem you run into is using HDMI connections at 1920x1080 resolution. If the monitor or TV is smart enough and the video card can communicate with it, everything will work fine. The problem is that sometimes you run into a manufacturer that trims the outer 50 pixels off each side so no "frame" is visible. This dimension just happens to correspond with the size of the taskbar as well as the upper left window control icons. The resolution you have to use here is 1776x1000. Any program (such as Visilogic) will throw any dialog boxes to the primary monitor, even if you're running the program on the extended desktop monitor, as Deke pointed out. This is a Windows thing. In short, I would not wish the additional support grief on the Unitronics staff for multiple monitors. Programming software is secondary to our main product, PLC's. I'd prefer that R&D focus on enhancing the functions available for us to work our control magic. Free Programming Software = You Take What You Get. Joe T.

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First, verify which type of analog input you are using. You didn't say which V130 and which snap IO you are using, and they can be either 10 or 14 bit, but not 12. That makes a big difference in the X1 and X2 values. Also, is your transducer outputting 0-10V or 4-20 mA? Reverse the X1 and X2 parameters in the linearization block to reverse the scaling. Let's say you have 14 bit analog on a 0-10V input signal = 0-5". X1 = 0 X2 = 16384 Y1 = 0 Y2 = 5000 (implied 5.000) For 0-10V = 5-0": X1 = 16384 X2 = 0 Y1 = 0 Y2 = 5000 Joe T.

Those devices do work, but you have to install software on any PC that you'll be connecting to the M91 over the network. The software creates a virtual com port on your PC (so you still use U90 in serial mode) and packetizes the commands to that port, sending them on the network to the converter. Joe T.

You've got to use CANbus cable, as two of the conductors are designed to carry the bus power, and the other two are twisted and shielded. Cat 5 isn't the same. Call your cable supplier and tell them you want some Allen Bradley DeviceNet cable - the "thick" stuff. Belden cable I'm not sure if the star topology will work either; it's not real clear in the Unitronics documentation. One of the home boys will have to answer this. Sorry. Joe T.

You don't have to modify the sensor- the RC circuit gets connected directly to the PWM output. Here's an example: PWM circuit Just Google "convert PWM to analog voltage" and you'll find all kinds of good stuff. Joe T.

That is a question for your sales office. They want to know the environment the units will be installed in and how many units are involved. I've got a lot of units in the field that have been running for more than five years. What's the rest of the story? Joe T.

It looks like you can convert the PWM to 0-5V, which you can read with the -E3XB module. I looked through the data sheet, but they didn't give R and C values for your filter - you may be able to contact the manufacturer and have them send you a circuit. Time to start wiring stuff up and see what works. Joe T.

Here's the datasheet on the sensor: SHT11 The V230 allows you to access the serial ports from the program, but it's RS232. You'll have to convert this to the 5V TTL level the sensor is looking for. You can buy an assembled converter or integrate an IC into your circuit using something like the MAX232 chip. Here's one I found: RS232 converter As for the programming side, read all the Help and study the examples on the Protocol function block. You may be better off looking at a humidity sensor that has an analog output, since you already have an EX3B expansion module- Humidity Transmitter Good luck! Joe T.

In the United States the warranty is two years, unless we find water tracks on the circuit board, blown up traces, or a screwdriver hole in the touchscreen. Joe T.

I have done this, and the PWM output works well. I found a frequency setting of 100 worked in my application. Also remember that the Duty Cycle goes from 0 - 1000. Make sure you use a DC SSR, such as a Crydom D1D20. I realize this is a 20A relay, but it's only $10 more than the 7A unit and you get a lot more wiggle room. You won't need a heat sink at this low current. Joe T.

So the 10.4" screen has finally been released, with a product announcement and everything. The resolution and color depth are much better than the V570 and V350. Has anyone actually taken a V570 project and moved it to a V1040? Do the objects automatically move to adjust to the new resolution, or is it like changing a V130 to a V350 where you get a 1/4 scale of graphics in the corner and you have to basically redraw every screen? Joe T.

Details, details! http://ftp.unitronics.com/Downloads/BETA/VisiLogicSetup_900.zip I haven't played with this yet as I have the bad habit of developing customer code with the beta software. Then I have explain to them where to find a copy of it. Then they have a question on a new feature and the Help isn't written yet. In other words, proceed with caution. Joe T.

If by NAS you mean Network Attached Storage then it's not something you can initiate from the PLC itself. You'll have to manually connect to the PLC with the SD Card Suite and manually move it unless somebody has a method I don't know about. Joe T.

A PID loop with tight parameters and the update time set as fast as you can make it will probably do the job. Take some time and thoroughly read the Help on the PID block as well as looking at the examples. You can feed the setpoint into the PID block and directly map the output register to it. Joe T.

The version swapper does work, but it's a little confusing to set up. You have to override the default settings and install different versions of Visilogic in different directories. Carefully read the Help on how to do it. Joe T.

You're going to have to re-write the logic anyway, so consider this: If you absolutely positively need a lot of floating point registers, then Unitronics will not work for you. Automation Direct uses a Siemens-ish dynamic memory allocation with its V-memory, so you can have pretty much whatever you want until you run out of memory. A problem with this is that you have to manually keep track of where all your variables are, and since a float takes four registers they don't fall on even boundaries. Then there's the possibility that you can overlap them with each other and with your regular integers. Careful planning will avoid this problem, but it's still kind of a pain in the butt. I do not use floats for analog scaling because it's almost never necessary. If the scaling can't be done with regular integers, there are also 255 signed long integers available. Consider the resolution of a floating point number in a PLC - you get seven digits of precision and a two-digit mantissa. A signed integer has a maximum value of 32,767, and a signed long integer has a maximum value of 2,147,483,648. That's 9.2 digits of precision and there are no rounding errors. I only go into float land if trigonometric functions are needed. Unitronics has a built-in HMI, as you already know. Displaying data on this HMI is much easier and more controllable using integers with virtual decimal points. To the user, the data looks the same and it's much easier to keep track of in the program as all the integers are individually numbered. Plus, the software is free and there is never an upgrade charge. As opposed to a $395 buy-in. Take a long look at the Unitronics instruction set; it is intuitive and there are a lot more instructions available to you than Automation Direct. Keep in mind that this is my personal opinion and I do not work for Unitronics, but I have been a distributor for them for 10 years. I have been programming PLC's for 23 years and have programmed them all, as I also do system integration work. Unitronics simply offers the most bang for the buck. Joe T.

Rockwell bought the rights to the device, and successfully used the technology to vault themselves to #1 in the US in the 80's ad 90's You'll notice that in the AB tradition, the finished product is massive and does way more than the user needs. Way too much trivia circling my brain Joe T.

Don't forget the datasheets- The second datasheet reveals the amazing power requirements, as evidenced by the NO-BLO fuse protection. Joe T.

How fast is the shot? If the whole thing's over in a few seconds, a PID loop won't be fast enough. Please describe your process in more detail. Joe T.

For starters, manually set your baud rate to 115200 and try to connect. Joe T.

If you really want to go big... Come up with a module that has an HDMI output. Then we could plug it into a 50" TV bought at the local electronics store. YEAH, BABY!! Joe T.

If you're using the Unitronics USB-Serial converter, the driver that comes on the CD doesn't always work. You need the latest driver for the Prolific PL-2303 from their website: http://www.prolific.com.tw/eng/downloads.asp?ID=31 Joe T.

High probability that the PLC is locking up from inductive transients - I've experienced this. Do you have RC snubbers or flyback diodes on all your inductive loads? The reverse EMF that is caused by something as small as two plug-in octal relays releasing at the same time can find its way into the I/O module through the board traces can cause this kind of hiccup. Joe T.