safety relay: MSR124RT

In this relay, what is the differnce between X1/X2 loop and Y1/Y2 loop? Both have to be closed to energize K1 & K2, right?

the light curtain is also being checked
Y1.Y2 is the manual reset push button

timing wise
1. push reset button
2. light guard contact check
3. energize K1 and K2 contactors simultaneously
4. K1 and K2 contacts Opens X1 and X2 input
5. this sequence is precisely timed.
- SYSTEM now normal
Should any of these fail the outputs 13.14 and 23.24
will be locked out and can not energize

iant said:

3. energize K1 and K2 contactors simultaneously
4. K1 and K2 contacts Opens X1 and X2 input

Click to expand...

Before the sequence number 3, if X1/X2 loop was open (meaning the NC contacts did not close, or X1 & X2 were not wired at all), would K1 & K2 still energize?

Msr124rt

unsaint32 said:

In this relay, what is the differnce between X1/X2 loop and Y1/Y2 loop? Both have to be closed to energize K1 & K2, right?

Click to expand...

Not to cut across you Ian, but I thought I'd explain these terminals in a little more detail...

The X1/X2 loop is technically known as the "Monitoring Feedback Loop", but is more commonly referred to as a "Monitored Output Loop". It verifies that devices wired to the Safety Outputs have de-energized correctly. As you can see they are wired in series through Normally Closed auxiliary contacts on the Safety Contactors K1 and K2. When the Safety Contactors are de-energized, the X1/X2 loop is closed. This closed loop is one of the prerequisites to Resetting the Safety Function i.e. the Monitored Safety Relay (MSR). It is optional. If you are not using Monitored Output, then you can loop out X1 and X2.

Y1 and Y2 are as Ian mentioned, the Reset terminals. The MSR124RT has a couple of Reset methods...

Automatic Reset: Here there is no Manual Reset push-button. You loop out the Automatic Reset terminals X5 and X6. Monitored Output is still optional. So if X1/X2 are looped out (No Monitored Output), and Automatic Reset X5/X6 is also looped out, and the Safety Channel Inputs from a light-curtain, gate, or E-Stop are closed, then the Safety Relay will automatically reset.

Some people gasp at this! Surely not? But it is permitted to Auto-Reset a Safety Function immediately upon the closure of the Safety Channel Inputs, under certain cirmcumstances. As always, a Risk Assessment will determine if it is permitted or not.

Manual/Not Monitored: As it states, the X1/X2 Monitoring Output loop is not used, so again, X1/X2 are looped out. Here a Manual Reset push-button is used, and is wired across Y1/Y2. Once the Safety Input Channels are closed, then the Manual Reset can be actuated.

Manual/Monitored Reset: This is a Monitored Reset, not to be confused with the Monitored Output feature. Again, a Manual Reset push-button is used across Y1/Y2. Monitored Output (X1/X2) is still optional here. When the Safety Channel Inputs are closed, this MSR incorporates a 5 second delay before you can Reset the Monitored Safety Relay. After 5 seconds has elapsed, a Leading Edge from the actuation of the Manual Reset push-button is required to Reset the MSR.

unsaint32 said:

Before the sequence number 3, if X1/X2 loop was open (meaning the NC contacts did not close, or X1 & X2 were not wired at all), would K1 & K2 still energize?

Click to expand...

Hopefully the above makes it more obvious, but if not...

The MSR will never Reset, using any method, if the Monitored Output loop X1/X2 is not closed. As I said, if you do not require it, you can loop it out.

Regards,
George

this safety relay is a SIL-3 or CAT.4 type its function is
to detect a failure of components before it the system will energise the twin contactors.
the reason I mentioned the operation in sequence.
if you were to look at each number as a timed step each step is tested before the next step begins

remember - or note
a contactor has three parts (this type is a Safety contactor

part 1 - COIL
Part 2 - High Current Contacts
part 3 - Auxillary Contacts ### mechanically tied to PART 2
the AUX contacts mimic EXACTLY THE MAIN CONTACTS
also called forced or guided contacts

(with a standard contactor or relay the main contacts can weld together)


but the auxillary can still function)

the Idea of automatic reset of light curtains is a direct part of the machine's written risk analysis process.

Manual reset is normally for a lock oout in case of the guard being broken. the guard then needs to be reset

Geospark said:

Automatic Reset: Here there is no Manual Reset push-button. You loop out the Automatic Reset terminals X5 and X6. Monitored Output is still optional. So if X1/X2 are looped out (No Monitored Output), and Automatic Reset X5/X6 is also looped out, and the Safety Channel Inputs from a light-curtain, gate, or E-Stop are closed, then the Safety Relay will automatically reset.

Click to expand...

Now I am wondering about X5/X6.

So, the difference between Y1/Y2 and X5/X6 is.... Y1/Y2 must go from open to close to reset, whereas X5/X6 being closed automatically resets (if X1/X2 already closed for both cases). If so, if X5/X6 are closed, manually closing Y1/Y2 must have no effect. In other words, either X5/X6 or Y1/Y2 is used, never both.

Did I get ir right?

what is it you want to do
these relays are multi use
the wiring depends on how you want it to work

unsaint32 said:

...either X5/X6 or Y1/Y2 is used, never both...

Click to expand...

That is correct. As Ian says, they are multi-optional safety relays.

X5/X6 is Automatic Reset, but is also known as AutoStart. I prefer the former, as the term AutoStart is misleading, and may imply that the machine itself automatically re-starts after the relay automatically resets. This I would say is, or should normally, not be the case, but can be, again under certain circumstances permitted by a Risk Assessment.

I too am curious to know if you are only learning in general, or have a specific application for this MSR?

It is important that you understand how it works, but remember, this is how this specific MSR works. Some of its features are generic, and some of its features are not generic with other AB MSRs. Across all safety relays, from the different manufacturers, and while adhering to minimum standards, there will be generic features and proprietary features. You have to choose the correct safety relay type to suit the Risk Assessment for the application. Most manufacturers will provide all options across their safety relays, but just because a relay has an option, does not mean you can use it.

Integrators may have a preference for a particular manufacturer's safety relays, but you cannot, or should not, have a preference for an individual safety relay that you use for every application. If one relay happens to fit the bill each time, then that's fine, but you shouldn't be in the habit of just adding a generic safety function to anything that moves.

G.

I am a maintenance guy. In our applications, the safety relays output contacts are used to enable another safety relay for another machine, complete a robot (IRC5 6600) controller run chain, and to enable VFD control for conveyor. I was more curious about the SR than anything. Thanks for the valuable education Ian and George.

Sung

remember the other safety relay should also have N/C contacts to confirm they don't weld either

unsaint32 said:

In this relay, what is the differnce between X1/X2 loop and Y1/Y2 loop? Both have to be closed to energize K1 & K2, right?

Click to expand...

X1/X2 is your contact state check. Since you're supposed to be using contactors with mechanically linked contacts, if one N.O. contact welds, the N.C. contact will likewise be stuck open, and when an E-Stop is pushed or in this case the light curtain is broken, it will see that the contact closure on X1/X2 was not remade, and thus will not allow the system to run even if the light curtain is cleared and the reset button is pressed.

Y1/Y2 are your reset button. It only needs to see this momentarily. If everything is kosher, it will start the motor.