AB Micrologix 1200 Reset

  • Thread starter Andres Valderrama
  • Start date

Thread Starter

Andres Valderrama

I downloaded a program which constantly writes to the communications port of this PLC, now I am unable to go online, is there any way to reset or erase the PLCs program memory??
I'm not 100% familiar with the 1200, but the procedure should be the same as for any of the series.

1. remove any battery.

2. remove any memory module (I don't think that this is an option on a 1200)

3. locate the memory backup capacitor and short
the leads.

All of this is of course done with the power removed, since it will be on the bench.

Call AB tech support at 440-646-7800. They are
usually quite helpful.

Eric M. Klintworth

You can use the communications toggle pushbutton to set the controller
to the default communications mode; hold the button 1 second. See page
4-2 of manual 1762-UM001B-EN-P, available from ab.com or
theautomationbookstore.com or your A-B distributor.

Eric M. Klintworth, PE
Columbus, Ohio

If you have set up the communications port for a communications mode (like
ASCII) that does not support regular programming, you can get the
MicroLogix 1200 back into DF1 Full Duplex by pressing the small grey "COM"
button under the cover next to the serial port and the trim pots. The
"DCOMM" light will come on, indicating default communications. You should
be able to use the RSLinx DF1 driver now.

If you need to halt processing in the controller (the MicroLogix 1000 and
1200 lack a keyswitch), one way is to power it up with an expansion module
added or missing; the I/O configuration fault will halt the processor

The MicroLogix 1200 is a powerful little controller, but all the serial
features mean there are a few ways to paint yourself into a corner; the
COM button is meant to get you out of that situation.


Si Ud tiene arreglado el portal de comunicaciones para un modo de
comunicationes (como ASCI) que no soporta programas normales, puede
devolver el MicroLogix 1200 al "DF1 Full Duplex", solo tiene que marcar el
boton pequeno gris "COM" debajo el cubierto, al lado del portal serial y
los "trim pots". La luz "DCOMM" va a encender, que le indica
comunicaciones 'default'. Ya puede usar el RSLinx DF1 driver.

Si Ud necesita parar el procesamiento en el controlador (los MicroLogix
1000 y 1200 faltan un interruptor), una manera es ponerlo con poder con el
modulo de expansion anadido o faltando; la configuracion I/O parrara el
programa procesor.

El MicroLogix 1200 es un controlador pequeno y poderoso, pero todas las
caracteristicas seriales significan que hay algunas maneras de enredarse.
El boton "COM" es la manera de sacarse de este situacion.


Ken Roach
A-B Seattle