Created Date: March 19,2004

Created by: RHanrahan

Is there some code that can be added to the ladder logic in a 105 series PLC that will have it bootstrap itself into run mode during a power cycle? I have had DL-130 spontaneously change from the Run to the Program state and this then requires the customer to send it back to put it back into the run mode. I seem to remember that A/B SLC-500 has this ability. This has happened to me often enough that it is becoming a problem. This should probably be something that applies to all PLCs across the board.

Thanks,

Bob

Created Date: March 23,2004

Created by: MacS

Bob,

I agree, that information is kinda hard to find unless you know where it is.

If your 105 is dropping out of run mode you will probably want to look for the root cause. One likely possbility is switching inductive loads using the onboard relays without surge suppression on the inductive load coil. See page 2-22 of 105 User for some details.

If this is not a possibility in your system give us a call to explore what the cause might be.

Created Date: April 01,2004

Created by: franji1

Originally posted by mboyle:

Will this work with a DL-260 PLC?

The 105 does not have a switch for program/term/run mode, but the 260 does. If you want your 260 to always come up in run mode, place the switch in the Run position. Also, if it is left in Term, I believe it comes back up in its last state.

So if you want to be able to power it down in terminal switch position in program mode, but then come back up with the switch in the terminal position with it in run mode, you may need something like the 105, but this does not appear to be "normal " behavior.

Created Date: April 02,2004

Created by: ericn

Originally posted by franji1:

If you want your 260 to always come up in run mode, place the switch in the Run position.

Just keep in mind that placing the switch in the RUN position is 'Forced Run '. Stuff like operator terminals will NOT be able to write to the PLC through the com ports!

I have some customers flip this switch to the RUN position ( 'cause they want the machine to RUN!), then call me when their operator interface no longer works. I now monitor SP11 (Forced Run Mode). If it's ON, I trigger a display to say "Put the switch back to TERM ". Saves a lot of needless service calls.

I'd like to see that switch be replaced with a spring-to-center version so this can't happen.

-Eric

Created Date: April 02,2004

Created by: C R Williams

I agree with MacS you probably should be asking why this is happening.

I have found that a really effective power filter is a cheap and cheerful personal computer Uninteruptible Power Supply (ie on sale at Staples or wherever). This, and careful attention to segregation and bonding of power and signal grounds fixes most problems.

I am operating a DL260 right next to a 460v 3phase 300kW phase angle SCR power supply (which the plc is controlling) without problems, but the design of the cable routing and termination was, shall we say, interesting.