AB cable advice

Good afternoon all.
I've been tasked in getting a 2711R-T4T PanelView 800 4.3” communicating with a AB SLC5/03 PLC.

This was a system which was working in the past with another HMI (which stopped working) and the 2711R-T4T PanelView 800 4.3” is its replacement.

The top channel 1 RJ45 port is used for comms with an Intouch Scada network.
So I will be using the bottom Channel 0 RS232 port for comms with the panelview.

Before I go to site and investigate, I want to check about the correct cable.
I have the following two cables and wondering if they are suitable.
1. 1756CP3/A I'm pretty sure this cable is ok, but its my own programming cable and I need it.
2. 1761 CBL-AC00 SER.A AIC To Controller Comms Cable, very short but may work.

Any help or advice would be greatly appreciated.

Regards Padraic.

If I'm remembering correctly, the cable from the PLC to the HMI through rs232 has to be a straight through cable and not a null modem.

I've taken the screenshot from the Panelview manual.

Hmm... I might be messing up the other panelviews (programmed in FTV ME) with this one (programmed in CCW). I apologize for my incorrect statement.

I recommend a 1747-CP3 equivalent. Those are "null modem" cables that swap the Rx and Tx conductors (pins 2 and 3). You should be able to use any null-modem cable, or a straight through cable with a null-modem adapter.

The 2711R-T4T has both a screw-terminal connector (RS-422 and RS-485) as well as a DB9 style RS-232 port. You should use the RS-232 port.

While you have several protocol options with the 2711R touchscreen terminal, I strongly recommend ordinary DF1 Full Duplex on the RS-232 port. That is the default setting for Channel 0 of any SLC-500 controller at 19200 baud, 8/N/1 framing, and CRC error checking.

Hi and thank you for the comprehensive information. Form the information I’ve been given, it was set up as DF1, but I will have to figure out what way it’s set up in the PLC.
Hopefully one of the cables I have will work rather than having to make a cable on-site.

Regards Padraic

Hi all, I've been to the site and investigated this issue. Steps I've taken so far.
1. I went on line to the plc to ensure the RS232 port is working and to check its settings.
AB DF1
Baud rate - 1200
Station Number (Decimal) - 00
Parity - None
Error Checking - CRC
Stop Bits - 1
Protocol - Full Duplex

2. On the HMI I'm using Connected Components Workbench (CCW). I uploaded the application, checked its settings.
The Baud rate was incorrect, so I set it correctly and downloaded the updated application.

Still no communications.

The settings I'm not sure about is the station number. The PLC is 00, should the HMI be 01?

Any advice or tips would be greatly appreciated.

Regards Padraic.

With regular DF1 protocol, the station number should not matter. I'd be inclined to try a null modem adapter on your cable after you have verified all the other settings are correct.

I don't have any experience with that model of Panelview, but if you can get your laptop to talk to the PLC through that same cable, that should prove the only possible culprits are the HMI settings and cable.

The default baud rate for Channel 0 is 19200 baud, not 1200. In my opinion you should change both the controller's configuration and the touchscreen's configuration to match at 19200.

In DF1 Full Duplex Point-to-Point, the station numbers are typically 0 and 1 for the PLC and HMI, or 1 and 2. Technically it shouldn't matter unless DF1 Passthrough is configured on the PLC.

Check to be sure that hardware handshaking is turned off for the Channel 0 serial port on the PLC; 1200 baud sounds suspiciously like there was an archaic modem attached at one point.

And be sure the SLC is set up for Channel 0 to use the "System" configuration for DF1 Full Duplex, not "User/ASCII" configuration.

I would verify the serial port is working normally by trying to connect to the SLC from my computer using RSLinx Classic.

Hi Ken, thank you for the tips. I did go online to the PLC on my first visit and confirmed the port is working and the check the settings.
I revisited the site today and tried a few things.
On the HMI controller settings,I set the baud rate to match the port settings (1200), then changed the controller name to match the controller defined in the tags page. This solved the issue and I got communications between the PLC and HMI.
As advised by you Ken, to change the baud rate to the default. I couldn’t do as the plant was running and I didn’t want to go downloading to the PLC.
Thank you to everyone for all the tips and advice. This job is now closed out.

Regards Padraic