Do-more H2 (Micro Modular PLC) Videos

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Using UDP messaging with the Do-more is easy. You just create a UDP device and then use

PACKETOUT and PACKETIN instructions to send and receive messages. That's it. For example, suppose we want to send a short

15 character ASCII message from a PC to the Do-more via UDP. Let's say the message looks like this. Each three character set would be a parameter

of some kind that the Do-more needs to respond to. The underscores aren't used, they were added

to make the data easier to see when we look at the message in the data view. To read that into the Do-more via UDP we just

create a UDP Port Device. Click on the Configure button, then click

on Device Configuration. Click on New Device and create a UDP Connection. Give it a name -- we'll call ours UDP_Demo

and let's listen on port 60001. The only port the DoMore uses is this 28784,

so you can use anything else from 1 to 65535, just make sure it is compatible with your

network. Be careful, most lower numbered UDP ports

have predefined uses, so I usually avoid lower numbered ports. When you write this project to the Do-more,

this device will listen to the Ethernet port and capture ANY message sent via UDP to the

port you put here. All you have to do is wait for the device

to say it has a new message, and then get it from the device. Since we just created a device, DoMore designer

automatically creates a structure for that device. Let's open a Dataview and take a look at it. Device structures begin with a dollar sign

and the name of our device was UDP_Demo. When I hit the DOT I see this device has 3

structure members available. One tells me packets have been captured and

are ready for me to use, one tells me how many packets are available and one tells me

a packet was sent. Let's use the PacketAvailable member as a

contact to tell us when the DoMore has received a UDP message to that sixty thousand and one

port. When this contact tells us that this device

has received a packet, we just a PACKETIN instruction to read the message from the UDP

Device. Here is the UDP device we created. When a packet is received, it has the senders

IP address and UDP port in the message. Those will get put in whatever variables we

put here. You can then use those in your ladder code

to filter out the messages -- maybe you need to respond to messages from one IP address

differently than messages from another IP address. Or maybe you need to respond differently to

messages from one port vs another port. Something like that. Here you can specify a timeout Now you may

ask, "What do I need a timeout for if I'm just reading data from a buffer -- especially

since the Packet Available structure member just told me it's ready to go?" We'll you really don't. For us, in this little example here, and probably

most of your projects too, it's not a big deal. Just take the default. However, if you are interested in how it might

be used, then checkout the Do-more help file. This is actually a really powerful feature

for large complex projects. Let's change the number of bytes to read to

64 so we can use a String Short right here as the place we want the message to end up. Keep in mind we could have created a special

string size just for this message -- the Do-more allows you to create ANY string size you want

- but we're gonna be lazy here and just use the built in string short. Well, that's it. Step 1: Create a device in configure and Step

2: use a PACKETIN to read the data when the device says it has a message for us. Easy. Let's add String Short 0, D0, and V0 to the

dataview so we can see what happens when a message is received. Accept Changes. Save the project and write it out to the DoMore. Now if I send my 15 byte message from the

PC to the DoMore, The UDP Device we created collects the message for us, it sets a flag

telling us a message is available and we read the message from the Device into SS0. We also see that D0 and V0 got populated with

the senders IP Address and UDP Port. Perfect. What if in addition to receiving messages

from the PC, you want to also SEND a message to the PC from the Do-more? Easy, just use a PACKETOUT instruction. It's needs the exact same information: the

device that is handling the messaging for you, the IP address and Port number you want

the message to go to, and the data you want to send. Done. What if you send a message from the PC and

the DoMore doesn't get it? What do you do now? I like to use a free open source program called

Wireshark. This guy shows you every packet being sent

across your network. That's usually a lot of data to sift through,

so you will want to add a filter. To filter on the Do-more's IP Address, I simply

type ip.addr double equals and the Do-more's IP address. Now I only see messages to or from the Do-more. I'll send a message from the PC and sure enough

I see that a message was sent from my PC's IP Address, to the Do-mores IP address, via

UDP using these ports. And down here you can even see that 15 characters

were sent and what they were in hex. So at a glance you can now tell that the message

actually left this IP Address, it went to this IP Address and which UDP Ports that were

used to send the message. Usually, if a message isn't received, the

destination IP address or the UDP port number don't match what the Do-more is expecting. You just need to make sure the DoMore project

matches these numbers. As a reminder, the Do-more's IP Address is

here under the Info Button. The UDP Port is here under the configure button. Please keep in mind that Wireshark is NOT

and Automation Direct product, so please don't call support asking for help with that. There are lots of excellent video tutorials

on YouTube and the Wireshark website at www.Wireshark.org. Of course, if you have any questions about

Automation Direct's products, don't hesitate to contact Automation Directs Award Winning,

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