Nowadays I just use one cable. An ethernet cable. Then I do all safeties over profisafe, (or ethernet/IP safety, depending on customer) and then setup DCS safeIO to respond to estop events and stuff like fence open or NTED enabled.
However, prior to that, how you approach your safety circuit really depends on the size of your cell. One robot? Just run the chains through the contacts of the fence and estops, no safety relays needed. Two robots? Same, but add another set of contacts to each device. More than two? Safety relay for each robot's e-stop chain and fence chain.
I'm going through the same thing now, and in terms of Safety Inputs I'm all convinced that relays are not needed, but what about dropping power to energised equipment, controlled over robot IO?
I was thinking to use single safety relay connected to safe output to shut off voltage for all auxiliary equipment.
I could put just a rule in pmc regarding to shut all DO off once the safety is compromised but it is not considered safe by fanuc and relative standards.
I have never connected safety equipment directly to my robotics cards. I use electronic relays in a thin structure that can be used for rail mounting. It reacts perfectly fast, the contacts are not sticky and they are very long lasting.
if you want the robot to be the "master" safety device, you'll need to use safety relays, which in turn will cut off power to peripherals.
if you want the robot to be the "master" safety device, you'll need to use safety relays, which in turn will cut off power to peripherals.
There is nothing else other than the robot in these cells.
I'm going through the same thing now, and in terms of Safety Inputs I'm all convinced that relays are not needed, but what about dropping power to energised equipment, controlled over robot IO?
I was thinking to use single safety relay connected to safe output to shut off voltage for all auxiliary equipment.
I could put just a rule in pmc regarding to shut all DO off once the safety is compromised but it is not considered safe by fanuc and relative standards.
There is a safety PMC option that you can buy that will allow you to do safety level logic in the PMC.
As far as I know, Safety PMC only helps to build logic in a more convenient manner than Safe IO Connect, but doesn't have certified blocks to program safety functions (like monitoring of e-stop or door) - at least not in acordance with European standards. So this means, that each component still requires a safety relay, which is then connected to robot's safety input.
Correct me if I'm wrong.
excerpt from DCS Function Operator's Manual MAROBDLCH04121E Rev. H:
The following is the significant differences of Safety PMC function from Integrated PMC function.
- Safety PMC function is the safety function as Category 4, PL e, SIL 3.
- Safety PMC function can output to Safe I/O.
- The available signals of Safety PMC program is only Safe I/O and internal relay(R). Safety PMC
function cannot use the normal I/O such as DI/DO
This seems like you can do your safety logic in the Safety PMC to monitor e-stop's, door sensors, etc.
it's a safety function, as Safe IO Connect is. You can either write:
---|Estop1|---|Estop2|---|Estop3|---|Estop4|---(EstopOk)---using Safety PMC, or:
SPO[1:EstopOk] = SIR[1] AND SIR[2]
SIR[1] = SPI[1:Estop1] AND SPI[2:Estop2]
SIR[2] = SPI[3:Estop3] AND SPI[4:Estop4]using Safe IO Connect - and get the exact same result. The more complicated the system is, the more convenient it is to use Safety PMC instead of Safe IO Connect.
The problem is that you can't properly evaluate/diagnose/monitor the status of each safety device, which can be done by means of any proper safety PLC (pic related). That's why safety relays should be used - to ensure all that.
And in this case, the SPIs mentioned in the examples above should come from the relays' outputs.
The problem is that you can't properly evaluate/diagnose/monitor the status of each safety device, which can be done by means of any proper safety PLC (pic related). That's why safety relays should be used - to ensure all that.
And in this case, the SPIs mentioned in the examples above should come from the relays' outputs.
Safety plc and relays would be 2 different things, I would say either use one or the other.
What monitoring of devices you want to do except for checking consistency of OSSDs and EDM? Those 2 things should be doable using DCS safe I/O and interconnect.
For me it looks like a single relay to cut power of the external devices circuit should be enough though.
There is a safety PMC option that you can buy that will allow you to do safety level logic in the PMC.
Still not considered safe as standard Digital I/O is not considered safe, so overwriting it's status with safety signal won't make it safe, even if the PMC have safe functionality.
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Question,
We always add on safety relays to add as addition to the safety input to the robot. I always thought this was unnecessary due to the safety inputs for the Fence and E-stops to already be redundant and self monitoring.
Do you wire E-stops directly into the ESTOP circuit on the robot or do you use something in between?
Is the Robot completely control reliable by default?
Thanks in advance!
Which controller? If it happens to be an R-J2, I just recently went through the entire safety circuit on one less than 24 hours ago, so it's still pretty fresh in my mind.
Edit: Also it depends what exactly you're trying you potect/prevent. There are various safety checks being sent back and forth to all the components for all sorts of things. And yes the controller checks and rechecks multiple things at different times, depending on what's happening. Need more specifics
Safety plc and relays would be 2 different things, I would say either use one or the other
That's what I mean - you either use a safety PLC, or Safety PMC/Safe IO Connect with safety relays.
IDK if it's allowed to write some arbitrary logic for different safety devices. They should react to different events (like reset) in a defined manner. That's why these ready-made blocks are available in safety PLC programming tools - they are certified "black boxes" that can only have some signals assigned to them - but their working principle cannot be changed.
Safety relays work in a similar manner to these program blocks - you can connect some predefined signals to them, but can't influence the way they work.
Im Having this same kind of issue but I think there wiring it wrong...I added 2 safety relays and I have the prints that show which sfdo and sfdi they use. sfdo12 and 22(SPO2) sfdo13 and 23(SPO3). also sfdi13/23(SPI3) and sfdi14/24(SPI4)
Im trying to setup the Safe IO, but keep getting DCS-448 PLSCHK alarm(sfdo22) They want one relay to E-Stop signal and the other to V-Stop Signal(gates OK)
Ive spent a lot of time and cant figure it out!! can anybody walk me thru this PLease.
You need to supply power from the same source to the 24v and gnd in the estop board controller. The pulse check is not getting through. I was fighting that for at least 3 days couple of weeks ago.
So the sfdo12 gos to A1 and sfdo22 to A2. Dcs24v gos to NO contact and machine 24v that want to be safe to other.. sfdi13 and 23 go to NC 
That sound correct then how do I set up the safe IO connect with that, I’ve read safe IO manual but still not understanding what I’m doing wrong
