SLC 5/04 Communications

[Old_Mate88]

G'Day Guys,

I've currently got 4 x SLC 5/04's that I am changing some programming on using the RS-232 DF1 Driver. I have successfully done the programming on 3 of these units, but the 4th one is being difficult.

Every time I go into the Auto-Configure I am getting the dreaded "Failed to find the Baud and Parity,Check all cable and switch settings". Even though it is the same setup as the others ( 4 x generators all the same in a small power station).

I can't imagine it's the cable, and it isn't connected through a switch, I'm hoping that the CPU isn't stuffed. Any ideas?

Cheers,
Matt

 

[Mickey]

Even though it is the same setup as the others

Are you sure?

Do you have the offline program for this unit? If so check its port configuration.

Is there anything normally connected to the serial port on this unit?

 

[Old_Mate88]

Hi Mickey,

Yeah mate, I’ve put the offline programs side by side and checked both Channel Config and Controller Properties against each other. All the same for Channel 0, I checked channel 1 as well just for kicks.

There is nothing usually plugged into the serial port.

Really got me stumped.

Cheers,
Matt

 

[JesperMP]

Are the SLC5/04 CPUs on the same DH+ network ?
If so, you can use pass-through from one PLCs serial port, via DH+ to the other PLC.

Maybe they are not (since you said they are identical, and thus the DH+ node addresses would be duplicate).
In that case, and if you dont have any adapter to go online directly via DH+, you could temporarily change a reachable CPUs node address, enable pass-through, and then go online to the other PLC that way.

 

[Firejo]

If there isn't a program in the SLC5/04 that you need to keep, you could always default the processor. It sounds like the channel 0 port is not configured for DF1 full duplex. If you default the processor the port will become a DF1 full duplex port with a baud rate of 19.2K, 8 data bits, 1 stop bit and no parity.

To default the processor, with the rack powered down, pull the processor and unplug the battery. Somewhere close to the battery connector you will see a can type capacitor. On the other side of the board, short the two pins from that capacitor together (the cap is acting as a temporary battery to keep the memory alive. Shorting it will dump its charge and the memory will get wiped). If you're not comfortable shorting the cap you could just let the processor sit for a few hours with the battery unplugged. Either way, once the cap has been discharged plug the battery back in and re-insert the PLC into the rack. Power the rack up and the PLC should flashing the fault LED indicating that there is no program loaded. RSLinx should now be able to find the PLC.

Keep in mind you will need to download a new program into the PLC before it will let you go online. It can be nothing more than just the basic PLC (I.E. no ladder logic) but I've always found it a good idea to make sure the key is in the program position to prevent the PLC from faulting if it finds something that doesn't match between the hardware and the config file loaded into it.

 

[Old_Mate88]

Hi Jesper,

They are on the same DH+ Network and they have all different node addresses, aside from Run hours this is only thing different on the Programs.

I can however only see the one I am currently plugged into on the network for some reason, I'm assuming that this is because even though the Node# is different the file/PLC names are the same. I've checked the files and Passthrough appears to be enabled.

I might try renaming one of the files and then seeing if I can talk to multiple Generators on the network.

Thanks!

 

[OkiePC]

It has been over a decade since I used the passthrough feature, but I don't believe it will support going online with multiple devices at once. If you can connect a PC to the DH+ network, you should see all the nodes available and be able to connect to more than one at a time. Be aware, though, that every DH+ device on the token passing network may have its communications affected by this. I had some networks ata previous job with 8 to 12 nodes including HMIs, and the HMI's would get noticeably sluggish when I had more than one instance of RSLogix fighting for its turn with the token.

 

[Mickey]

See pdf below for how to setup SLC and RSLinx for passthru DF1 to DH+

Can you post the .RSS file for the SLC in question. (zip it first)

 

[JesperMP]

Yes, passthrough has to be enabled in the PLC that is to be "passed through". Then, in RSLinx you can browse to the target PLC by expanding the pass-through PLC.
(from memory, 15 years back at least)