Suppose you need an ESTOP a Light Curtain and a Safety Mat to control your machine.
And suppose you want a 2 second audible alarm when the machine gets shut down.
And let’s add an indicator that stays lit for 5 seconds if the shutdown was caused by
the light curtain or safety mat.
To do that with discrete components, you would need an ESTOP Safety Relay, A Light Curtain
Safety Relay, A Safety Mat Safety Relay, and some timing modules to provide the pulses
for the alarm and indicator.
And then you would have to wire all of this up, find space for it in your cabinet and
document it.
And if you need to modify it later?
You have to do it all again.
And don’t forget you need to create a report on all of this for the safety validation.
The good news is you can do all of that logic and timing and interconnect with just a single
Safety Controller.
And if your machine needs to see relay contacts instead of the OSSD outputs from the controller,
then you can add a relay module that uses external wiring for remote locations or you
can add relay modules that talk to the controller over the bus so you ahve no interconnect wiring
to mess with at all!
And all of your documentation and data you need for your safety validation report are
done with just a single click of a button.
Let’s implement that exact example in the Mosaic Safety Controller from AutomationDirect
just so you can see how quick and easy it is to do.
We’ll pick up where we left off in the previous video with a full ESTOP implementation.
We just need to add a light curtain … and a safety mat.
I’ll go ahead and assign pins to all of these new inputs.
This zoom down here is a quick way to give yourself some more room, so you can spread
things out to make room for new stuff.
Let’s delete these guys so we can start clean.
We want our machine to be active as long as the ESTOP is giving us an active signal AND
the light curtain is giving us an active signal AND the safety mat is giving us an active
signal.
so, let’s delete this wire … grab an AND … drop it on the screen … and wire the
ESTOP to it and it to the output.
We need three inputs on the AND gate so just click on it and go over here to change the
number of inputs.
Now we can wire the light curtain and the safety mat.
Perfect – now if any one of these is used, the output will turn off.
We want to sound an alarm for two seconds when the output is turned off, so let’s
click on the output and enable a status output and let’s grab a status output block and
drop that on the screen.
Now, before we wire that, we want to turn that falling edge into a 2 second pulse, so
we go grab a monostable B function block which does exactly that and drop it on the screen
and wire it up.
We want it to output a pulse that is 2 seconds long and we want it start when the status
into it drops so we leave this unchecked.
We do want it to automatically reset each time.
Well that’s great except for one thing.
When the status drops, this WILL produce a pulse, but it’s inverted from what we need.
The little graphic on this icon even shows you that.
So, we need to invert this signal.
How do we do that?
We COULD use this invert function, BUT there is an easier way.
Just right click on this input and look – it added a little bubble here.
That means this input will be inverted!
Exactly what we need.
We also want to light an indicator for 5 seconds when either of these are used.
That’s exactly what we just did, so I’m going ot copy these three blocks, paste them
in and get them in the right place.
Wire everything up and change the monostable to a 5 second duration.
And we want to invert that signal too.
Done.
Let’s verify it.
Uh-oh!
We got an error.
Ahh, it says some I?O’s are missing pin numbers and that the Safety Mat requires test
signals.
I love that the software dims all the blocks with issues.
So, let’s assign pins to the outputs … and add click on the safety mat so we can add
the test signals it needs.
Now if we verify it, it says everything is OK, so we connect – enter the default password
which is SAFEPASS - and upload … I went ahead and modified the wiring in my
demo rack like this – added the safety mat and test signals.
And added the light curtain.
And added the two status outputs like this.
OK, The programming is done, so we can drop into monitor mode to restart the controller.
Our ESTOP was set up with a manual reset, so I’m going to reach over and preset the
reset button to get the outputs back on-line.
Hit the ESTOP – Output Turns off and the Audio signal stays active for 2 seconds.
Perfect.
Undo the ESTOP.
Reset the system.
Break the light curtain – The outputs turn off, 2 second audio AND a 5 second indicator.
Perfect.
Reset the output.
Step on the mat – Output shuts down, 2 second audio AND a 5 second indicator.
Perfect.
Reset the output.
That’s it.
You should have a pretty good feel now for how to use logic and timing in your programs
AND how much easier it is than trying to wire all this stuff up with discrete safety relay
modules.
And look at this, one click of a button and all of the safety validation data you need
for your report is ready to go.
You don’t have to spend all that time figuring it out yourself.
To me, that’s worth the price of admission all by itself!
We have only skimmed the surface here.
There are lots of other functions over here that will make your life so much easier so
take some time to experiment with them.
Remember – simply right click on any block to bring up help on that function.
Wouldn’t it be great if you could try all of these functions WITHOUT sending the program
to real hardware?
Well, guess what ... Mosaic Safety Designer has a built-in simulator and that allows you
to do just that – test your program BEFORE trying it on real hardware.
Which means you no longer have to use your expensive hardware as a crash dummy guinea
pig for a program that may or may not work.
We’ll learn how to use that simulator in the next video tutorial.
Click here to learn more about Mosaic Safety Controllers.
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