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Hi All

I purchased a new V1210 for a customer and have been developing a chunky bit of code to drive 64 pumps in various modes.

The date time is becoming reset to 1st Jan '06  It also only happens on power cycle, not on reset or when downloading new code.

I've checked all the obvious stuff:

1. Put in a new battery

2. Checked the battery status bit is fine (in fact I've built in a small piece of code that checks it if is set and the plc starts beeping and a battery icon flashes) until the user presesses confrm at which point I do a reset.

Either I hadnt noticed or it has only started happening recently (about a month into development) - I reckon its the first option though; I have just started working on the shcedule bit that triggers on time so ony now am I paying attention to the time.

Any thoughts anyone?

Could I somehow be inadvertently triggering some state that resets the date/time?

Many thanks

 

Mal

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Thoughts entering the brain..........

Unlikely scenario but check......Is the new battery actually OK?  Does the status bit change correctly if you put in a dud/leave out?  Perhaps the system is power cycling without you noticing, and incorrect battery status is a root cause.

Associated with above, what I/Os are you using, and are they all powered/wired correctly, and through fuses etc?  Perhaps an error somewhere is causing a big enough dip to repower everything when certain I/Os activate everything they have.

cheers,

Aus

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Thanks Ausman!

At this stage I have not connected up the output modules - I'm using an expansion port with 4 x IO-TO16, these are powered by a 3.5A 24V supply which is separate to the PLC power supply which I made the same to avoid mistakes.

So key thing here is that the PLC is the only powered unit at this stage.

Yep the battery is good measuring 3.2V (I think.. I'm not in front of it right now). 

I've checked the battery status and watch it drop after a few seconds when I pull the battery out so confident its not there.

As an update, the supplier reckons it might be a fault where the RTC is not being powered by the battery so when the main supply cycles the RTC resets.

I believe all the operands are retaining their values but will do a more formal test on that to be sure. 

In the mean time the supplier is sending a replacement unit and we'll see how that goes.

 

Cheers Mal

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Hi again Mal,

2 hours ago, MalSnaize said:

these are powered by a 3.5A 24V supply which is separate to the PLC power supply which I made the same to avoid mistakes.

As an aside, clarify this please.  Will the modules power up at exactly the same time as the PLC, or are you meaning you now have everything commoned to one supply.  Don't forget recommended commoning of 0V if separate.  Also, depending on what you are running via the transistors, is 3.5A going to have enough headroom running the modules and all 64 points?

2 hours ago, MalSnaize said:

the RTC is not being powered by the battery so when the main supply cycles the RTC resets.

If the values are being retained, this would be a fairly easy thing to check if you can be bothered undoing things a little.  It could simply be a dud solder point on the crucial chip leg. Of course, I'm assuming the 1210 is still using a separate RTC chip on the board!

cheers,

Aus

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Hi Aus thanks for your additional thoughts.

Attached is a very crude diagram of what I've done; note that this config is phase 1 with 2 x 16-port modules.

You'll see that I not planned to common the 0V (though the power supply earths are commoned on the DIN rail.

So what I understand from your comment is that I should common the two power supply 0v lines - is that correct?

 

On the power side of things, I am running solenoid/air process pumps which are rated at 15mA each - I'm quite confident that one 3.5A @24V power supply will handle that load but if I do see any issues I have the second power supply which is currently opnly driving the PLC so plenty of capacity left over - do you agree?

On the point of taking to the PLC with a soldering iron, it's only a couple of months old and there are far handier swordsmen than I who are less likely to poke a hot iron through the screen :-)

cheers Mal

Afeed Schematic sm.png

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Crude diagram?  Hah...it's great.  You should see some of my initial sketches of unusual things before they go to CAD!

Common the lines?   Yes, but I was more talking about the expansions and also how everything needs to power up at exactly the same time as the plc.   I only ever use a single power supply for an entire system, but I know that Joe T routinely earths all his negatives....quote:   "I usually ground the negative of my DC power supplies."  I'm assuming he is talking about multiple supplies, but perhaps not.  Pls chime in Joe, if you think it necessary! Either way,  commoning of the negative is a logical thing to keep volts consistent throughout the system, and if it is commoned onto ground is perhaps even better.  Me being the pernickety person I am, I would also ensure all the different supplies are at exactly the same volts as well, through tweaking their adjusters.

I am intrigued by such a small current for those solenoids.  Sounds like some small pneumatic robot stuff, which I am not into at all.  Are there any specs for their initial draw?  Most solenoid coils draw far more than rated until the core is correctly pulled into position.  Worth checking to ensure your switching capacity/method is ok and durable. 

cheers,

Aus

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:-)

Yep these are small process pumps (https://www.smcpneumatics.com/smcdigitalcat3/docs/processpump/processpump/PB.pdf) which are being used to deliver various liquid feed an treatment into tanks.

I believe the internal works use a solenoid to "flip" a valve which allows air to actuate a diaphagm which delivers the fluid. So in fact air is doing the heavy lifting and the solenoid just triggers the actions so doesnt carry any significant load.

They are quite cool litte pumps with tiny footprint and capacity of up to a litre a minute being dispensed.

 

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