Going online with a 1747-L531

Im trying to go online with this 1747-L531 and Rslogix wont recognize it Im using the 485 port w\ 1747-UIC and my switch is set to 485.
I have gone online w\ this p.c. on other controllers so my port recognition is ok, any tips would be greatly appreciated.

some suggestions ...

here are a couple of quick things to check:

try changing the “Node” address of your computer’s DH-485 driver ... if the node address of the computer conflicts with the node address of the SLC, then you won’t be able to communicate ...

try changing the “Baud” rate of your computer’s DH-485 driver ... normally the DH-485 port on the SLC is left in the fastest setting (factory default is 19,200) but someone COULD have reduced the speed ...

try increasing the “Maximum Node” address of computer’s DH-485 driver ... the default setting is “31” ... if someone has set the SLC’s node address for something higher, then your computer won’t be able to find that node address when it polls for activity on the network ...

also ... someone COULD have configured the SLC’s DH-485 port for “shutdown” mode ... this would have the effect of turning the port off completely ...

question: what is the “DH485” LED on the front of the SLC processor doing? ... if you’re lucky, it should be continuously flashing “on” for about two or three seconds ... then “off” for about one second ... that’s its way of “polling” the DH-485 network and trying to find someone out there to talk to ... if the LED is always “off” then the port may be “shutdown” or possibly defective ... personally, I’ve never seen one defective before ...

The L531 is a relatively new controller (about 3 years old, I think). If your RSLogix 500 hasn't been updated since the controller's firmware came out, RSLogix 500 won't recognize the controller and cannot go online with it.

Not to split hairs but it is not rslogix that communicates with the PLC it is RSLinx. Open RSLinx and perform an rsWHO
/communications/rsWHO. Also look for errors listed next to your driver /communications/configure drivers, also check the dh485 light on the front of the PLC as listed above.

Let us know what you see.

Marc