AB 440CR30 Programmable Safety Relay

[cjarvis64]

Working with this unit for the first time, is there a way to make this unit behave like a safety relay, as in break a PLC output based on inputs from a safety device, i.e. light curtains or an E-Stop? I want to bring a PLC output to an input on the 440CR30 unit and then connect a solenoid valve to the output side of the unit - which instructions in CCW would make this possible? Or am I thinking of this unit all wrong? It's confusing to me why they would have sourcing outputs on this controller and not relay outputs - they even call it a 'programmable safety relay.'

Thanks

 

[Robobob]

If you want relay outputs there is a plug in addon module available. Part number 2080-OW4I. This will give you 4 relay outputs. The outputs are not safety rated thought.

 

[cjarvis64]

If you want relay outputs there is a plug in addon module available. Part number 2080-OW4I. This will give you 4 relay outputs. The outputs are not safety rated thought.

They aren't safety outputs though. Is the idea to source your PLC relay outputs with this safety relay? I don't understand how else the 440CR30 unit would work without the help of force-guided relays, which is what I have planned to implement.

Edit: I just now saw your edit adding that the relay output plug in module is not safety rated

 

[arpus4KM]

Working with this unit for the first time, is there a way to make this unit behave like a safety relay, as in break a PLC output based on inputs from a safety device, i.e. light curtains or an E-Stop? I want to bring a PLC output to an input on the 440CR30 unit and then connect a solenoid valve to the output side of the unit - which instructions in CCW would make this possible? Or am I thinking of this unit all wrong? It's confusing to me why they would have sourcing outputs on this controller and not relay outputs - they even call it a 'programmable safety relay.'

Thanks

use it in conjunction with IceCube Safety relays.

700-HPS2Z24, etc

 

[Ken Roach]

why they would have sourcing outputs on this controller and not relay outputs

Because the outputs are "OSSD" (Output Switching Signal Device) devices, not just ordinary PLC-style sourcing outputs. OSSD outputs are often used in pairs, with an output voltage feedback sensing circuit and tiny delay, which allows both short circuits and cross-wiring to be detected. That's the sort of redundancy and self-testing that contributes to high performance / safety levels.

I suppose RA calls it a "Programmable Safety Relay" because of the programmability: you can use it with various kinds of safety circuits like E-stops and light curtains and cord-pulls and pressure mats and two-hand control, depending on how it's programmed.

Your application sounds like it's better suited to a dedicated-purpose safety relay with series contacts. I have used dozens of the ordinary 440R-S12R2 single-input safety relay with dual-channel E-Stop buttons to interrupt power to a light-duty load through the two output relay channels in series.

 

[JeffKiper]

We don't use safety relays at all anymore. We use CR30 for everything, the diagnostic feedback can take a long troubleshooting time to zero with those few LED on the face of the unit.

As Ken has stated OSSD are for switching. Whe they fail statistically they will fail in the safe conditions. When you use EDM (External Device Monitoring) in conjuction with a 700-HPS2Z24 as arpus4KM stated you can monitor that the unit is switching to the correct function. Ie when I say switch off, the relay sill feedback a signal and say I switched off.

Think of this as a "Configurable safety relay". The safety inout goes to this unit not the PLC. This unit handles all the logic for the safety then it can be a signal to the PLC.

I try to explain it as input , logic , output. Just like a PLC. In safety my goal is to keep people then machine safe. By historical design with tried methods removing the hazard is (safestish with some exceptions). If you take all the inputs to the PLC and rely on the PLC to pass the data to the safety circuit you have just introduced another point of failure in to the safety chain. Lets reduce these to the needed minimum.

Sorry Im rambling I've been up since 5am yesterday and am having a liver biopsy today. Im a little excited somy thoughts are all over the place.

 

[joseph_e2]

We don't use safety relays at all anymore. We use CR30 for everything, the diagnostic feedback can take a long troubleshooting time to zero with those few LED on the face of the unit.

As Ken has stated OSSD are for switching. Whe they fail statistically they will fail in the safe conditions. When you use EDM (External Device Monitoring) in conjuction with a 700-HPS2Z24 as arpus4KM stated you can monitor that the unit is switching to the correct function. Ie when I say switch off, the relay sill feedback a signal and say I switched off.

Think of this as a "Configurable safety relay". The safety inout goes to this unit not the PLC. This unit handles all the logic for the safety then it can be a signal to the PLC.

I try to explain it as input , logic , output. Just like a PLC. In safety my goal is to keep people then machine safe. By historical design with tried methods removing the hazard is (safestish with some exceptions). If you take all the inputs to the PLC and rely on the PLC to pass the data to the safety circuit you have just introduced another point of failure in to the safety chain. Lets reduce these to the needed minimum.

Sorry Im rambling I've been up since 5am yesterday and am having a liver biopsy today. Im a little excited somy thoughts are all over the place.

Jeff: I hope the biopsy goes well (as well as possible...)


I used the CR30 a few times at my previous location but found the I/O count to be too limited relative to its price. It was very useful if used in conjunction with a Logix 5000 PLC over Ethernet to get diagnostics out, but...by the time its cost was more attractive than traditional safety relays it couldn't match the complexity of the safety relays.


Here, I've used the Keyence GC-1000 programmable safety controller a bunch and really like it. The logic options are more extensive than the CR30, the IO count is higher and expandable (with safety IO), and they have instructions for adding it to an AB PLC (MicroLogix 1400 and Logix 5000 systems) for diagnostics and communications. Their price point is less than the CR30 as well. Frankly, in my experience, there's nothing the CR30 can do that the GC-1000 can't do better...except have its program be contained within a Logix 5000 project. It even has a color LCD screen that provides diagnostic info.

 

[dummy_bit]

We've tinkered with the CR30, but in the end we just went with a safety rated CompactLogix controller so we have one less part number to accomodate for.

I detest working with CCW anyway...

 

[JeffKiper]

Jeff: I hope the biopsy goes well (as well as possible...)

Thank you.

20 years ago I had a fall out with Keyence over a $30.00 light curtain bracket. I was mad and made this statement "I will never buy or use another Keyence product". It cost me a few jobs that had them spec'd.

The CR30 integrates nicely with 5k as you said. On a small stand alone machine I will add a small HMI for diagnostics. What we have found is we can make an extremely complicated safety relay system with traditional relays, but troubleshooting for the general maintenance team is time consuming. I typically have my kids, wife or someone from the customers office look at the HMI and tell me where the problem is with the system when we are doing commissioning. That little bit of diagnostics just helps so much.

 

[JeffKiper]

We've tinkered with the CR30, but in the end we just went with a safety rated CompactLogix controller so we have one less part number to accomodate for.

I detest working with CCW anyway...

I prefer 5069- safety as well. I we have to have a small system where cost becomes an issue a CR30 usually fits the bill. CCW for CR30 is OK the Micro800 suck.

 

[travispedley]

I just had a 700-HPS2Z24 failed CLOSED on an e-stop circuit. I didn't think they were capable of that. E-stop failed to drop output power and air dump sol. CR30 output was off, no power on the coil of the HPS, and it was still energized. What the heck do you do after that??

 

[joseph_e2]

I just had a 700-HPS2Z24 failed CLOSED on an e-stop circuit. I didn't think they were capable of that. E-stop failed to drop output power and air dump sol. CR30 output was off, no power on the coil of the HPS, and it was still energized. What the heck do you do after that??

Use redundant relays, both monitored.

 

[JeffKiper]

I just had a 700-HPS2Z24 failed CLOSED on an e-stop circuit. I didn't think they were capable of that. E-stop failed to drop output power and air dump sol. CR30 output was off, no power on the coil of the HPS, and it was still energized. What the heck do you do after that??

What safety category was the circuit designed to? Any mechanical component is going to fail eventually. If the system qas 2 channel you should have caught the failure on the first channel fault.

 

[kamenges]

Originally posted by travispedley:

I just had a 700-HPS2Z24 failed CLOSED on an e-stop circuit. I didn't think they were capable of that.

As stated, they are most certainly capable of failing closed. What will NOT happen, however, is the OTHER contact being open at the same time. That little fact is what makes this a safety relay. You are guaranteed (to within some miniscule percentage) that the two contacts will always be in the same state regardless of the command state. It is the functional basis of monitoring.

Keith

 

[g.mccormick]

As stated, they are most certainly capable of failing closed. What will NOT happen, however, is the OTHER contact being open at the same time. That little fact is what makes this a safety relay. You are guaranteed (to within some miniscule percentage) that the two contacts will always be in the same state regardless of the command state. It is the functional basis of monitoring.

Keith

So that means that if you are monitoring the NC contacts in your sfety loop, then the safe off position will not be true.

This is also the only way that those safety rated relays are of any value. I have seen (still do) people insist on using the safety rated ice cube relays in a "safety" system, but not do any contact feedback with them. All I can do is sigh and grumble.

I