Slc 5/04 Communication Problems

localman

Member
Join Date
Sep 2022
Location
Minnesota
Posts
12
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!
 
the serial to usb converter software may assign a different serial port.
liik in your com settings to see which port is actually being used when the cable is plugged in and change the rslinx setting to match that port.
i hope this helps,
james
 
Do you have an offline program file indicating what the comm settings in the PLC are? While the default setting is for DF1, it is quite possible that it has been changed (eg to DH485, which would require additional hardware to connect).
 
I check and always change the com port in rslinx to what I see in Device Manager. I have done this multiple times and cannot seem to communicate with the plc
 
Do you have an offline program file indicating what the comm settings in the PLC are? While the default setting is for DF1, it is quite possible that it has been changed (eg to DH485, which would require additional hardware to connect).
I do have an offline copy of the program. I will check that and see what it is assigned as
 
I don't have the cable specs handy, but you will need a null modem serial cable to connect to the serial port on the 5/04. In RSLinx Classic, make sure the RS232 driver is set to the right COM port (visible in the PC's Device Manager) and then autoconfigure with the PLC connected. If it fails, first thing to try is a null modem adapter. If you absolutely can't get it to work...try with another 5/04. That PLC's port may be bad.
 
I don't have the cable specs handy, but you will need a null modem serial cable to connect to the serial port on the 5/04. In RSLinx Classic, make sure the RS232 driver is set to the right COM port (visible in the PC's Device Manager) and then autoconfigure with the PLC connected. If it fails, first thing to try is a null modem adapter. If you absolutely can't get it to work...try with another 5/04. That PLC's port may be bad.
I got a null model and i tried it and it didn't work. I still have not been able to communicate with the PLC. I dont have another Slc-5/04 plc to try it
 
This is the channel configuration found in the offline version of the PLC.

Because the channel is set up for Half Duplex Slave, you will need a tad more info in order to attempt to use the serial port for communicating with it using the DF1 Polling Master driver.

You need to know the Slave ID number, baud rate, and error checking method and then you need a good RS232 to Serial adapter and some luck to get that driver to work.

Get a screenshot of the Channel Config with the "Chan. 0 - System" tab selected.

Here's a good thread on the topic where Ken Roach breaks down the details very well:
http://www.plctalk.net/qanda/showthread.php?t=126718
 
Last edited:
Get a screenshot of the Channel Config with the "Chan. 0 - System" tab selected.


Can you do this? there is a chance the DH+ cable is the only what for it to work

The other way is.... reset the PLC to factory default and then download the program again after you change the system settings, but if there are any changes in the CPU that are NOT on the offline program they will be lost forever so its a risky way

OR other way number 2) Do you have a spare CPU? If I were you I would get one (cheap on ebay) and download your offline program and install it to see if it works as expected.

The other option is buy a DH+ cable, we sell an aftermarket one but its not cheap and the spare 5/04 would be your cheapest way.
 
Because the channel is set up for Half Duplex Slave, you will need a tad more info in order to attempt to use the serial port for communicating with it using the DF1 Polling Master driver.

You need to know the Slave ID number, baud rate, and error checking method and then you need a good RS232 to Serial adapter and some luck to get that driver to work.

Get a screenshot of the Channel Config with the "Chan. 0 - System" tab selected.

Here's a good thread on the topic where Ken Roach breaks down the details very well:
http://www.plctalk.net/qanda/showthread.php?t=126718
Thank you so much for this idea. I tried it and was able to connect to the plc. I tried everything on the thread you shared and was able to useDF1 polling master to connect to the plc.
 
Update!!!!

I was able to use the suggestion by OkiePC and use DF1 polling master. I changed every parameter that was set in the plc to match parameters in the Polling master. I was able to talk to the plc, make my changes and download to it.

Thank you every one for the support. I really appreciate it.
 

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