Slc 5/04 Cannot Comm. Via Dh+

[BadgerGuy 0]

I am trying to communicate to a SLC 5/04 via the PCMK DH+ the Settings I tried Device PCMK Network DH+ Station Name: RSLinx Station #1 Baud Rate 57.6K The Settings they gave me PLC 1747-L42B Driver it was written on AB-PIC-1 (this makes no sense the PIC is and RS232 driver and none is available to use on the SLC 5/04) Chan 0 DH485 Chan 1 DH+ It kept giving me an error that the node was duplicated in the system. Please help I Thanks

[gravitar 3]

DH+ problems aside, it does make sense that someone previously used the PIC driver to program that SLC. What the did was connect a simple crossover cable between the COM port on their computer and channel 0 on the SLC. Since DH485 is the selected protocol for that channel, the PIC driver is appropriate. This is a topic of much confusion for just about everyone when they first start programming SLCs. To explain it briefly (more detailed explanations have been given in earlier threads) when you choose the PIC on your computer, you would think that you were specifically telling it you've got a PIC module, but the computer doesn't see it that way. The computer interprets that selection as "any possible communication scheme that involves the DH485 protocol". The 1747-PIC is a passive device as far as the data is concerned.. the computer doesn't even know it is there. Electrically, of course, it does alter the signal. Certain devices have a port that is electrically compatible only with the PIC or its equivalents.. Channel 1 on the SLC 5/01, 5/02, and 5/03 is a good example of this. Certain other devices are directly compatible with the COM port on your computer, and therefore do not need the PIC. Channel 0 on the SLC 5/03, 05/04, and 5/05 are an example of that. What they all have in common is they all use the DH485 PROTOCOL to commpuncate with other devices. Make any sense? This comes up so often that when I get some time, I'm think I'm going to do a write-up attempting to explain A-B's proprietary comms protocols and see if it could be added to the forum FAQ. Now back to your DH+ problem! This one is probably pretty easy. Assuming your computer and PCMK card are set up properly and able to communicate, I think you have probably just set your computer to the same node number as the SLC. Typically people set their computer as node 0, and PLCs, HMIs, etc. as node 1, 2, 3, etc. Try changing the node number to 0 and see what happens.

[Ken Moore 23]

The default node address for the 5/04's is node 1, so gravitar's got you on the right track. You have your PC is setup as node 1 and the SLC is node 1, since node 1 already exists on the network, it won't allow you on. I'm not going to attemp to explain the serial driver thing, I hope someone more capabile such as gravitar does post a clear explaination in the faq section. We see a lot of questions concerning this, and it can be confusing, even for some of the more experienced users.

[oldgearhead 0]

OK, I am getting a headache from some simple RSLinx mental block. Exactly how do you set the station numbers. Do you create separate drivers for both the PC and the PLC? How? Must they be created under the same heading such as AB_KT-2. I just re-visited the RSTrainer for RSLinx and the sample program creates one driver, and as if by majic, both the PC(Workstation) and the SLC appears!! Isn't the driver that is configured in Linx for the PC, and dosn't RSLinx simply locate the PLC on the network. If that is the case, do you change the station number by right clicking on the PLC and edit something?????

[oldgearhead 0]

..From RSTrainer for RSLinx - Station = node, and "Node is an active device or workstation on a network identified by a unique address. For example when connecting a computer to a SLC 504 processor over a DH+ network, the computer node address could be set to 01 and the SLC node address to 02".again I ask: How? Do I configure a driver for the PC, and after the PLC 'appears' on RSWho, right-click the PLC and edit the node address? Also what is meant by 'Source ID' in the RSLogix channel configuration menu? How about 'Passthru Link ID?

[Ken Moore 23]

The node address of the PLC is set up in the channel configuration of the .rss file, you can change the node address of your laptop by selecting it in Rswho, then right click, > configure driver>highlight station number, enter in the desired node address. Ken

[gravitar 3]

You need only configure one driver, and this driver corresponds to the hardware in your computer that you are using to get on the DH+ network. If it is a laptop with a PCMK, you set up the PCMK driver. If it is a desktop with a KTX, you set up the driver for the KTX. you do not have to worry about a driver for anything else other than your computer. The "driver" in the SLC, PLC, panelview, etc. is pre-installed in the device's firmware. It is always present, you never have to add or delete it. When you first power the device up, you will notice that it goes through several initialization and testing steps. The driver is automatically loaded into memory during that step. Node numbers, station numbers, etc... Every device (computer, PLC, panelview, etc) must have a unique ID number. In some places it is called the "station" number, other places it is called a "node", possibly other names are used elsewhere. It is all the same thing, just a unique identification means for each and every device participating on a network so things don't get confused. When you first configure the driver on your computer in RSLinx, you assign the computer its node number. When you first power up a SLC or PLC processor, it defaults to node 1. You can change that when you enter or modify a program and download the program to the PLC, **OR** when you go online with an already-download program and make an online modification. You **CANNOT** make this change through RSLinx. RSLinx lets you see but not touch (so to speak). Panelviews default to node 2 and you can change that number by downloading a program to it or by entering the panelview's built-in configuration menu and changing it there. Don't worry about passthru ID numbers. Passthru is what it is called when you use the PLC to bridge between networks. In other words, you can plug into the DH+ port on the PLC, and download to a panelview that is on that PLC's RIO link. Or on a SLC, you can bridge between DH+ on channel 1 and DH485 on channel 0. Suffice it to say that is an advanced technique that you probably don't need to think about right now. And yes, it does seem like magic when you've been struggling with comms problems and suddenly see other nodes on the "Who" screen :)

[OkiePC 14]

Excellent topic idea I sometimes have to stop and think ... okay are they talking about an electrical spec like RS232, or a communicaiton protocol like DH485. I've played with the stuff enough to feel comfortable, but could use more formal instruction on the subject. Maybe a whole topic on the electrical side of things for various networks first, then with that knowledge, getting into the communication protocols and other layers would make complete comprehension easier.

[oldgearhead 0]

This is all great information. However, I still have a SLC 5/04 that I cannot make appear on either: 1) The the DH+ network using a 1784-PCMK/B PCMICA card with the 1784-PCM5/B cable. Only my PC shows up in RSWho? 2) DF-1 point to point, SLC port 0 to PC serial. Only my PC shows up in RSWho. However, if I connect the same set-up to port 0 on a SLC 5/05 (using auto-configure), the SLC appears in RSWho and I can connect.???

[OkiePC 14]

Let's start with the DH+ connection. Describe your network. Do you have multiple processors coneected to a DH+ network? Are they connected to each other with blue hose? You need to know the node numbers of all of them. Check online with the ones that you can talk to and check the offline file of those you can't. You need to know the baud rate or communication speed. Most common is 57.6k, but I think that 115k and 230k are now supported. Your Laptop will become another node on this network when you plug it in. In RSLinx, your DH+ driver settings must have the same speed and a UNIQUE node number. I use the high end of the range for temporary connections. All of our machines are 1 through 31. My laptop is node 70, and our maintenance computers are 67, 68 ,and 69. That way, they could all connect to the same network without conflict. You can edit these settings while disconnected without having to delete and recreate the driver. About the blue hose: The blue hose must be wired correctly, (daisy chained). DH+ should use the clear wire on pin one, and the blue wire on pin two. If it's backward, as long as they're all backward, it should work. That's just the AB standard to distinguish DH+ from RIO connections. Terminating resistors need to be installed at the ends of the network. Most of the time you can communicate without them. It's such a simple thing though so make sure they're there for fewer nusicance problems. 57.6k requires a 150ohm terminator. I believe the other two speeds call for 82ohms. Look it up tot be sure. In RSLInx, your DH+ driver should be "Running" and not say "Error" when you go to the configure drivers page even if you're not connected. The leds on the PLCs should be green solid when network coms are established. Green flashing (once every few seconds) means they're looking for the network. Red and red flashing, you've got a problem ... usually wiring. That's all I can think of for now. Let us know what you learn, and don't give up!

[oldgearhead 0]

Thanks Okie, I think your hint about the driver running before configuration did it. Works just fine now on DH+. I see 2 SLCs and 4 Panelviews on one network, and 3 SLCs with 3 Panelviews on the other network!

[OkiePC 14]

Great! Now I guarnatee (Joe Namath style) that you can figure out the channel zero settings. (look at channel config ONLINE) Gotta go work night shift, but I'll check again in the a.m...