[00:00] In this lesson, I'll demonstrate how to connect to a SLC using Data Highway Plus from a ControlLogix gateway. Before walking through these steps, I'd like to take a look at an example diagram. This diagram depicts three SLC devices connected to a ControlLogix gateway via Data Highway Plus or DH+ for short. To connect to these PLCs from Ignition, we'd need to navigate into the first PLC via its ENBT module, out one of its DH+ channels, and into one of the SLCs. We can tell Ignition how to navigate this route with a connection path, which is a comma separated list of numbers that tell it how to get to the target PLC. Connection paths will vary depending on your setup, so let's take a look at a table with the rules on creating one, and we'll build out this example. The first number is always going to be a 1, and that tells Ignition to move to the back plane of the first PLC. The second number is the slot number of the module to move to. In this example, we would wanna move to the DHRIO module in slot number 3. So the second number in the connection path would be a 3.

[01:06] The third number is the exit port or channel of that module that will be exited through. In this diagram, that depends on the desired PLC. If connecting to SLC X, then we would want to use the DH+ Channel A, which uses the number 2. If connecting to SLC Y or Z, then we'd use the DH+ Channel B, which uses the number 3. The fourth number is going to depend on the module we're connecting to in the target PLC. This will either be an IP address of an ENBT module, a ControlNet address, or a DH+ station number. In this example, we're connecting via DH+, and the station number will vary depending on the PLC. We would want to put "21" for SLC X, "40" for SLC Y, or "41" for SLC Z. A really important note about the DH+ station numbers is that these are octal, so be sure to put your station number in octal format and not in decimal format. If we were connecting to another ControlLogix device, we'd want to include another 1 and 0 to move to the back plane and then the processor, but that's not required with PLC5s or SLCs.

[02:08] Now that we've walked through how to build a connection path, let's see how this is actually done in Ignition. In my gateway webpage, I'll head to the connections section, expand devices, and click connections, and I'll create a new connection. In this case, I'm going to connect to a SLC, so I'll choose the Allen-Bradley SLC driver. I'll need to give the connection a name, so I'll just call mine SLC DH+. Next, I need to specify the host name or IP address of the ControlLogix gateway. In other words, this would be my first PLC. Then I need to enter my connection path. My path is gonna look a little different than the example we just looked at, but it's built in the same exact way. My first number is going to be a 1 to move to the back plane of my gateway. Then my DHRIO module is in slot number 6. I want to move out of DH+ channel A, so I'll need need to put a 2. Then the fourth number is the DH+ station number, which in my case is 1.

[03:05] Now that I have my specific connection path configured, I can create the connection. Once my device status says connected, I can see my tags by opening my designer, browsing my devices, and expanding my new connection.