How to put MicroLogix 1200 in Run Mode

I’m sure I am going to be embarrassed when I read the solution to my problem. The machine I’m working on has a Panelview 300 and a Micrologix 1200. The Panelview had to be replaced. I tried to modify the logic to allow the machine to run without the Panelview but that was futile.



The Panelview communicates with the PLC using a DH485 protocol. The PLC and my laptop use the DF1. When I download the program to the PLC, it changes the protocol for the communications port to DH485. I read a warning that I will not be able to communicate with the PLC after this happens. Sure enough I don’t.



The Panelview and PLC talk okay. However, the PLC is not going into run mode. I believe the only way to put the Micrologix 1200 in Run mode is through the program but I can’t access the program once the shift is made to DH485.



What am I doing wrong?



Thank you for your time and help;



Frank

I think you need a 1761-NET-AIC, you can get on ebay pretty cheap.

How did you get connected if the port was set to DH485 to do your download? If your PC has a real serial port you can use the 1747-PIC/AIC+ driver in RSLinx. To do this delete the DF1 driver restart RSLinx then add the 1747-PIC/AIC+ driver. Use the same cable. ( If no serial port you might want to consider getting a 1747-UIC ( USB to DH485 converter) for future use.)
If not, see pic below and set the bit to make the processor go to run mode on power-up. You will have to redownload the new changes to set this.

Thank you for your help.

I do have a 1761 AIC in the shop. I used it to transfer the program to the Panelview. It isn't too easy to take out to the machine I'm fixing though.

The Micrologix 1200 has a switch that shifts the protocol to DF1, allowing you to connect. The program you download changes that port back to DH485.

I have a PIC, as well as the 1747 UIC, but they both have an RJ45 type connector, the Micrologix uses a round DIN type connector.

I'm going to go back to the machine and put it back into DF1 mode. Maybe it will allow me to put the PLC in Run and then change the communications setting for the port.

I'll let you know how it turned out.

Frank

Your UIC has both a RJ45 port and a RS232 port. See PDF below.
Use it, it will work.

It's working - I don't know how.

The machine is running; everybody is happy.

Once more, I realize I don’t understand communication jargon. I think I’ll try to find the answers in another thread rather than go through it here.


I suspect the solution to my problem came about by activating that tiny button on the MicroLogix 1200. That button switched the protocol of the port but I don’t understand which was which. Under one condition the PLC would communicate with the PLC (that’s how I put it back in run mode). Using the other protocol, the PLC would communicate with the Panelview. There is more going on than simply changing cables.

Thank you Mickey for all your help. I didn’t see your earlier suggestion concerning a status bit. There was a small icon indicating a picture that covered your text. The picture never came through. Thank you for the info on the 1747 UIC. I was an early buyer of that device, the first customer at my local dealership. The thing didn’t work. After a very frustrating ordeal, we surmised it was bad and it was replaced. The replacement worked sometimes, which was a little better than the first one, but it ended up sitting in my tool box. Maybe I’ll give it another look.

Thanks again for all your help;
Frank

COM button

You have to press and hold the Com button on the front of the processor until the DCOM light comes on. At this point the port is in DF1 mode and you can communicated with the rs500 software through a serial driver in links. Same procedure to put it back. B. Childs.

For future reference, next time you download the program set bit S:1/12 (can only be set offline and downloaded). Then cycling power will clear any errors and put the processor in run mode.

If the Micrologix is within 50' of the PV300 and they're the only two devices on your DH485 "network" consider switching over to DF1 and avoid all the hassles that DH485 brings (with modern PCs).

The PV300 can have its firmware replaced to turn a DH485 unit into a DF1 unit. I did this myself on one machine that was set up the same as yours, and the PV300 was within 2 feet of the Micrologix. Not sure why the OEM chose DH485 in my case, except that perhaps some of their installations call for a more remote HMI.