Let’s create a full featured ESTOP function in the Mosaic Safety Controller with redundancy,
input monitoring, output monitoring, two channel OSSD outputs, status indication, error indication,
safety relay outputs with feedback and a manual reset.
Let’s use the workflow from the previous video.
Step 1 – Configure the system.
I’m using the same configuration as the previous video so there is no need to change
it here.
Now remember: Even though we are not using these modules in this tutorial, we do need
to show them in the configuration because they are connected to the controller.
The relay module is just a passive unit with relays and contacts inside so we don’t add
it to the configuration because the controller doesn’t communicate with it.
Of course, your configuration will probably be different.
Step 2 – Add components.
Let’s start with just a single channel ESTOP and then we’ll switch that to a redundant
two channel ESTOP later in the video.
You can then choose to use the one that your risk assessment requires.
And let’s add an OSSD output.
Step 3 - Assign an input pin … and assign the output pin.
Notice that the second output and the feedback pin are automatically assigned when you select
the initial output pin.
Step 4 – Wire them together both here and the external wiring like this: The ESTOP comes
in on this pin, the output to relays is on these pins and the aux contact feedback is
wired to the Controller reset pin so it can’t reset until it sees the external relays or
contactors actually worked.
Step 5 – Verify it – looks good!
Step 6 – Connect to the controller – remember the default password is SAFEPASS
Step 7 – Send the program to the controller Step 8 – Drop into monitor mode to disconnect
and restart the controller.
We don’t need a password for monitoring.
And sure enough if I press the ESTOP we see the trace turn RED and more importantly the
controller LEDs tells it output 1 is off.
If I release the ESTOP the controller automatically resets the output and turns the light Green.
Perfect.
Let’s change that from an automatic reset to a manual reset.
Turn of the monitor mode and click on the OSSD output.
Click here to change to manual reset.
I modified the wiring to add in a manual reset button here.
Let’s add an error and a status signal output while we are here.
Drag a status output onto the screen, copy and paste that.
And wire them to the assigned pins.
I connected the status pin to this green indicator like this.
Let’s tell it which outputs to use, and let’s label those too.
Ahh, now it’s much easier to tell what the intent of these pins are.
We’re not going to take the time to label everything else in this video, but I do highly
recommend it.
Great, let’s verify that, connect to the controller, enter the default password, and
send the new program to the controller.
Go into monitor mode to disconnect from the controller and get it running.
There is no default password for monitoring.
The first thing we notice is that the CLEAR LED is on – that tells us the ESTOP has
been cleared and the controller is waiting for us to issue the manual reset.
So, I’ll reach over and press the new manual reset button and sure enough our output turns
green telling us it is active, and the CLEAR LED went out.
Now if I press the ESTOP, the output turns RED telling us the ESTOP is being pressed.
I’ll release the ESTOP and we see the CLEAR LED is telling us the system is clear to be
reset.
When I hit the manual rest button … the output is running again, which we can also
see on the STATUS LED and the STATUS indicator we wired up.
And of course, the Monitor screen shows us the same thing: I’ll hit the ESTOP again.
Release it and issue a manual reset.
Perfect.
That’s great, but there is an issue.
What happens if this input gets shorted to 24 Volts.
Then pressing the ESTOP to open its contacts won’t matter, will it?
That’s a safety issue.
We fix that by connecting one of these test outputs to the input.
This tells the controller we are connecting our ESTOP input to the Test 1 output signal
on pin 13 instead of a static 24 volts.
So now the controller can monitor the estop input and if it doesn’t see the pulses it
expects, it will issue a fault.
Let’s try that.
Verify – got our OK - Connect, enter the default password, and send the new program
to the controller.
That was successful, so let’s open the monitor screen to disconnect and restart the controller.
Again, No password is needed to monitoring.
Normal operation hasn’t changed.
Controller comes up waiting to be reset.
I’ll press the manual reset button and the clear light goes out and the output turns
on.
Press the ESTOP button and the output turns off.
Release the ESTOP, press the rest button and we are back on line.
Now I’m going to take a wire and I’m gonna short out the ESTOP button to 24 volts.
Ahh, look at that.
The controller immediately turned the output off.
When I remove the short, the CLEAR LED lights up saying the coast is clear and we can reset
the system.
Perfect.
Can we use a 2 contact ESTOP to get redundancy?
Sure!
Stop monitoring.
Click on the ESTOP and instead of a single we want a double.
Let’s assign it a pin on the controller and add monitoring from test output two which
is on pin 14.
I modified the test set wiring to match that.
Verify.
Connect using the default password.
Send the program to the controller.
Looks good.
Let’ drop into monitor mode to disconnect and restart the controller.
Again, no password required for monitor mode.
The cis waiting to be reset so I’ll do that, and we are up and running.
Press the ESTOP and everything works as expected.
I’ll short out one of the ESTOP leads to 24 volts, and sure enough, the controller
shuts down the output.
Release the short, hit the manual reset and we are back up and running.
We are currently running a manual reset.
But what is this Monitored thing?
Well, the manual reset just looks for a transition.
The monitored version is the same thing, BUT it also looks for the falling edge too.
So, it has to see a pulse to reset the controller.
Again, additional safety.
The last thing is the K Time monitoring.
Look at this: if you right click on any object on the screen, you can get instant help on
that item.
This tells us that K Time monitoring limits the time between when and output goes active
and then the controller should see the feedback signal react.
You can set that time to anything you want.
Again, just another thing you can use to tighten up your safety system even more.
Would you normally use a safety controller to do just an ESTOP function – probably
not.
There are over two dozen ESTOP relay solutions on the AutomationDirect Website that will
give you a much more cost-effective solution.
But, if you know you’re gonna be adding at least two other safety devices like light
curtains, gate switches, foot switches, or sensor, or stuff like that … then you will
find adding those to a safety controller will be much easier, more cost effective and easier
to maintain.
Plus, you just click a button to generate the safety data you need for your report – that’s
a huge time saver.
We’ll see how to build and simulate multi-input safety systems with logic functions and delays
in the next video.
Click here to learn more about the Mosaic Safety Controller.
Click here to learn about AutomationDirect’s free award-winning support options and click
here to subscribe to our YouTube channel so you will be notified when we publish new Automation
videos.