Adding defrost cycle??

[brewstarke]

Does anyone have a suggestion on easily adding a defrost cycle (basically just turning an output off for 30 mins every few hours) to my fermentation control processes without re-writing each process? Or killing/restarting the process altogether (i.e. running a separate process containing a register that feeds to the running ferment process within ladder logic)

A little more info:
I use the BCS-460 for fermentation control where I've built temp ramps and holds around specific yeast strains that I use. The BCS controls a small dorm fridge that I've reworked into a smallish fermentation chamber (holds about 3 carboys or 5-6 cornies). Things have worked great up til we hit 90% humidity and 90 degree days.... Now my fridge coils get iced up and the temps rise to the mid 60's all the while the fridge is running; killing my electric bill, the fridge compressor and more importantly the Munich helles I'm trying to lager inside I've been trying to add a simple automated pause to the current running process (specifically the output controlling the fridge) through ladder logic and another available process to allow for a defrost cycle but can't seem to do it without having to restart the process. I can add this cycle to the various states I have running the fridge to cycle on/off to act as a defrost but I have a number of processes already created that are set up to run ramps and also track the fermentation times which will be restarted when starting/stopping the process. Also I seem to only need this added feature when it's humid and hot out and the fridge is running frequently so am hoping someone has a better brain than me when it comes to process control to come up with a solution that can be easily 'added into' my current system.

Any input would be greatly appreciated!

[JonW]

It sounds like what you need is a method to pause and restart your fermentation processes, which unfortunately, cannot be done.

How about using another process/output/relay to interrupt the output from your fermentation process. This way your fermentation process keeps running, but it basically just isn't powering the fridge during defrost cycles?

[brewstarke]

Yeah ideally a 'pause' controlled by an outside process/state/register would be the easiest.
As an immediate fix I've modified my currently running ferment process to control a previously unused output, then linked that output to the output connected to the fridge with a register (0) separating the two outputs. Then I created a new process (had one available) which runs a two state loop-assert register 0 for 1hr-- then off for 15 mins- essentially giving the fridge the option for juice for an hour then turning off for 15 mins regardless of the ferment process call for the fridge to chill. This should get me through the next few days. I guess I'll need to revise my other ferment process too.... although this issues got me thinking about devising a jacketed recirculating ferment temp control using the fridge coils in a container of gylcol with recirc pumps controlling the chillin. More precise control and no frost buildup. Hmmm.

[brewstarke]

As a quick followup on this- A better solution is to add a small fan that constantly blows on the coils- This solves the issue without diving into process control.