ML1100 & wireless ethernet?

[mike hartman]

Hi, I'm using 2 ML1100's over a wireless ethernet, the radios are RadioLinx. My Questions are:

1. Do I use the MSG instruction to read & write to N7 files?
2. I would like some suggestions on how to create a program that will constantly monitor the integrity of the wireless communications. A "Heartbeat" that lets me know that if I have pushed a "Motor On" PB. from a remote location, the motor will not stay on if there is an interuption in the radio frequency.

 

[panic mode]

i didn't try it but you should be able to simply use MSG instruction.
the MSG status bits should provide you with information like failed
connection (ER bit) etc but if heartbeat is what you want, it's still
dead simple thing to setup:

pick a bit in the transfered block,
let's say PLC A sets bit A, and the other will read it as A' and
also PLC B sets bit B and PLC A will read it as B'

ladder in PLC A can be

 



    B'                    A

---| |-------------------( )        (one is straight through...)

ladder in PLC B can be

 

    A'                    B

---|/|-------------------( )        (and one is crossover, hence NC contact)

The good side is that this adjusts to comm speed. The more frequent messages,
the faster the toggle. All you need to do is setup some WDTs in each PLC.
here is sample of what one PLC could use:

 



    A'

---| |-----------------------[TON T4:0 0.01 100] (check if stuck on)

    A'

---|/|-----------------------[TON T4:1 0.01 100] (check if stuck off)



  T4:0/DN             Comm_Timeout

---| |----+--------------( )

          |

  T4:1/DN |

---| |----+

 

[panic mode]

you can use Read instructions (obvious where the data comes from)and set alarm if comm fails (or even use FLL to wipe out MSG-ed block)