SLC 5/04 Communication Issue

jduong17

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Join Date
Mar 2015
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santa ana
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6
Hi I'm having an issue establishing a connection to a SLC 5/04 that is connected to a PanelView 2711-T10G8 via the DH+ ports, although I'm trying to connect to the SLC with a USB/RS232 cable from my laptop.

When I am configuring a new driver in RSLinx, I'm unable to establish any connection with the "1784-U2DHP for DH+ devices", "1784-PKTX(D)/PCMK for DH+/DH-485 devices", and "RS-232 DF1 devices" driver types.

I do not have a copy of the existing program on the SLC and I'm trying to extract that existing program. Any advice that could lead me in the right direction on doing this is greatly appreciated. Thanks.
 
Welcome to the Forum !

The correct driver for an RS-232 connection to the Channel 0 9-pin serial port of the SLC-5/04 controller is the "RS-232 DF1 Devices" driver.

Be sure that you have selected the correct COM port for your USB/RS232 interface.

Be sure that you are using the correct serial cable; the 1747-CP3 is the usual cable for this application. Any null-modem type serial cable will work. Be aware that serial cables for connecting to the PanelView's serial port are straight-through, not null-modem, and will not work.

Many USB/RS232 interfaces will not correctly perform the "Autoconfigure" feature, so use the default 19200 baud, SLC device type, CRC error checking settings in the RS232 DF1 Devices driver.

It's possible, though uncommon, for an unused Channel 0 port to be configured for a protocol that is not the default DF1 Full Duplex. In such a case, your best option is to have somebody with a proper DH+ interface perform the upload for you.
 
Ken thanks for the quick reply.

The correct COM port is selected.

I'm using a cable that I had previously used to connect to a MicroLogix 1100, I'm not sure if that qualifies it as a null modem type serial cable.

Also tried connecting using the default RS232 DF1 settings.

Is there some way to check what protocol the channel 0 is configured to? Basically I am working off of no knowledge of how this PLC was previously configured, but also want to rule out any other possible issues that it might be before having to bring someone in.
 
If you have the offline file you can check to see how the serial port is configured.

Or post it, the .RSS file ( zip it first) and someone will help take a look.
 
You might have confused the purpose of the various plugs on the SLC-5/04.

The three-pin "Phoenix" style plug and the 8-pin round Mini-DIN plug are both internally connected to the Data Highway Plus port, called Channel 1.

The 9-pin D-Sub connector is the Channel 0 serial port.

It's a little bit confusing that A-B uses 8-pin Mini-DIN connectors on dissimilar ports, but that's just a fact of life in electronics. Cisco uses RJ45 for both serial ports and network ports on the same switch, right ? A-B tries to key the connectors so you can't easily plug them into the wrong device.

Quite a lot of third-party cables omit the keying hardware and are easier to plug into the wrong thing.

If you don't have a 1747-CP3 cable handy, any ordinary straight-through serial cable with a null-modem adapter will work.

I used to tell people you can pick them up at any Radio Shack. Sniff.
 
Thank you for the info! I have a straight-through serial cable with a null-modem adapter and tried to connect using the RS232 DF1 device driver type, no dice.

But I also do have a 8 pin DIN connector to USB cable; since that plug on the SLC 5/04 connects to channel 1, would I be able to somehow set up a "proper DH+ interface" as suggested in your first reply?
 
Only the 1784-U2DHP will connect to a DH+ port from USB.

I'm not sure what sort of device your USB to Mini-DIN8 is. If you bought it from somebody who put an A-B part number on it but who is not a Rockwell Automation distributor, ask them what it's supposed to be.

90% of the time, the Channel 0 port is left at DF1 Full Duplex and all you have to do is set the driver to the defaults, but there are certainly instances where that's not the case.
 
The cable is actually a DIN 8 pin connector to RS232, which I plugged into a RS232 to USB cable... It's from Allen Bradley (P/N 1761-CBL-PM02) and I think it's specifically for communication with the MicroLogix units. It doesn't sound like the right thing, I was grasping at straws.

Anyway, to clarify once I configure the RS232 driver with default settings, using the 9 pin serial cable with null modem adapter, the device doesn't show up on the RSLinx main screen so I'm stumped.
 
Thanks for posting the clarification.

The 1761-CBL-PM02 is meant to plug into the RS-232 serial port of a MicroLogix controller. It probably didn't hurt anything when you plugged it into the SLC-5/04's DH+ network port, though I'm surprised it fit.


To be clear; the default settings for an SLC-5/04 (in fact, for all SLC and MicroLogix serial ports) are these:

RSLinx_SLC_Defaults.png
 
An update: so I did a little more digging and I found apparently what may be an offline copy of the program on the SLC (attached). It looks like Channel 0 is set to the DF1 Full Duplex protocol so I should be able to connect?

I also noted the baud rate of the file is set to 1200, and I tried configuring a driver with that rate and also changed the COM port to that in my computer settings with no luck... the troubleshooting continues.
 
Update: It turns out the "null modem adapter" I was using was not-so-null-modem-adapting after all... I figured this out after I tested for continuity across the pins... 🙃

I'm facepalming myself for not checking this earlier, but the lesson was learned.

Ken thank you again for all your help, at least I learned a lot about the ports and cables. I can already tell this forum is awesome.
 
Hey everyone, I am trying to communicate with a Slc 5/04 plc using the 1747-cp3 cable, RS232-DF1 driver and a laptop. I tried using a serial to usb converter (3 of them), and using the driver but was unsuccessful in configuring the driver.

I proceeded to use a docking station (connecting the 1747-CP3 cable directly to the docking station) without the converter and I am still unable to configure the driver.

I'm unsure what I am doing wrong and would really like some help.

Thank you all for your help!
 
Are you sure that the serial port of the docking station gets assigned as COM1 ?
You can check the serial port in Windows Device Manager.

Do you have a backup of the PLC program ?
If you can investigate what the CH0 port is set to in the offline program it can take away a lot of trial and error.
 

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