Any High temp programmable relays?

strantor

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Sep 2010
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katy tx
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A colleague of mine is building panels with physical relay logic and it's fairly labor intensive. Simple applications, maybe 10 relays. I encouraged him to use a "micro"/"brick" PLC aka Programmable Relay, like an Omron Zen, AD Click, or similar. He is hesitant because of heat. His panels are not climate controlled, they go into non-climate controlled spaces, and contain heat generating components. I don't know what temperature they get up to, but I'm trying to find the highest ambient temp rated brick PLC on the market, and if that isn't enough to budge him, then I'll just leave him alone about it. Any suggestions?
 
So far this is the highest rated one I've found. 85C/185F. Never heard of this brand. Can anyone here vouch for it? It seems maybe closer geared toward the hobbyist. Analog inputs 0-5V.
 
I have difficulty finding that Velocio operating temperature specification to be credible. You can see the materials and connectors and lack of heatsink or vents for yourself.

If I were choosing a controller for very rugged duty, I would use one intended for the mobile equipment business.

The Eaton HFX series are not the cheapest controller on the market, but they are built with automotive style Deutsch connectors and are rated for very high vibration and temperature; the datasheet says 105 C is the maximum operating temperature.

IFM's Ecomat Mobile are the other CoDeSys-powered rugged controllers I've investigated, but I'd believe their testing to 85C operating temperature more than others.
 
If you can get us an idea of temperature, that would really help. They may not necessarily be rated for certain temperatures, but I have seen micrologix 1000 and 1100 units in panels with very large rheostats, up on catwalks towards the ceiling of the packing plant I worked in that were at minimum 12 years old. The ambient up there was just over 120F on the catwalks, plus the moisture from the process, and extreme humidity from hot, high pressure water spraydown. We literally had painted steel panels where the doors had rusted off and these things were going strong. I'm sure the temperature in the panel was over 130 with the rheostat going all day.
 
Oddball products like that are not something I like to hang my hat on, they tend to come and go in the market, leaving industrial customers holding the bag for long term support.

Some of the major PLC suppliers offer a "harsh environment" or "extended range" version of their products, using words to that effect (but varying by marketing depts.). Not all of them do it for the inexpensive little micro PLCs, but some do. Typical for those will be 70C operation as the extended temperature range. The little Siemens LOGO! unit for example used to have an "extended range" version that took it from 50C to 70C, but I just noticed that now the standard unit is rated for 70C.

The thing is, you will find that most OTHER components are not rated for high temperature operation either. For example circuit breakers are calibrated at 40C and need de-rating for higher, contactors have to be de-rated at above 40C but max out at 60C and the little "ice cube" relays are usually 50C max, etc. etc. If he is using what are called "machine tool relays" they are typically good for 70C, but beyond that, it gets more and more rare to find anything that can take even 70C, let alone higher.
 
I have difficulty finding that Velocio operating temperature specification to be credible. You can see the materials and connectors and lack of heatsink or vents for yourself.

If I were choosing a controller for very rugged duty, I would use one intended for the mobile equipment business.

The Eaton HFX series are not the cheapest controller on the market, but they are built with automotive style Deutsch connectors and are rated for very high vibration and temperature; the datasheet says 105 C is the maximum operating temperature.

IFM's Ecomat Mobile are the other CoDeSys-powered rugged controllers I've investigated, but I'd believe their testing to 85C operating temperature more than others.

Thank you. I had never heard of those. I don't think it fits the bill of what I'm trying to pitch to him, but it does give me some ideas of my own for future projects. Thank you.
 
If you can get us an idea of temperature, that would really help. They may not necessarily be rated for certain temperatures, but I have seen micrologix 1000 and 1100 units in panels with very large rheostats, up on catwalks towards the ceiling of the packing plant I worked in that were at minimum 12 years old. The ambient up there was just over 120F on the catwalks, plus the moisture from the process, and extreme humidity from hot, high pressure water spraydown. We literally had painted steel panels where the doors had rusted off and these things were going strong. I'm sure the temperature in the panel was over 130 with the rheostat going all day.

I wish i had better info to go on, but I don't think he even knows how hot they get. Just that they get "hot" and he's been building them this way for years without issue. Hard to argue with that. But if he could cut the panel building time in half (and probably save on components as well) without any decrease in reliability then he could make more profit on them. I'm just trying to help him (nothing in it for me) but I'm not sure he's going to be open minded unless my case is pretty strong.
 
Oddball products like that are not something I like to hang my hat on, they tend to come and go in the market, leaving industrial customers holding the bag for long term support.

Some of the major PLC suppliers offer a "harsh environment" or "extended range" version of their products, using words to that effect (but varying by marketing depts.). Not all of them do it for the inexpensive little micro PLCs, but some do. Typical for those will be 70C operation as the extended temperature range. The little Siemens LOGO! unit for example used to have an "extended range" version that took it from 50C to 70C, but I just noticed that now the standard unit is rated for 70C.

The thing is, you will find that most OTHER components are not rated for high temperature operation either. For example circuit breakers are calibrated at 40C and need de-rating for higher, contactors have to be de-rated at above 40C but max out at 60C and the little "ice cube" relays are usually 50C max, etc. etc. If he is using what are called "machine tool relays" they are typically good for 70C, but beyond that, it gets more and more rare to find anything that can take even 70C, let alone higher.

Good points. I'm not going to ask him; I'll just assume he's taken all that into into account. And maybe your first sentence us among his reasons for doing things the way he does.
 
Kind of echoing what others have said, even cheapo PLCs have pretty high temperature ratings these days. The Micro800 series is rated to 149* for example. I'm sure they have some serious fudge factor built into that as well.

I'm really curious where these panels are getting installed and what kind of internal wattage is being generated. Hard to argue with going with what's worked for years, but even relays can die early with too high of temps for too long.
 
Kind of echoing what others have said, even cheapo PLCs have pretty high temperature ratings these days. The Micro800 series is rated to 149* for example. I'm sure they have some serious fudge factor built into that as well.

I'm really curious where these panels are getting installed and what kind of internal wattage is being generated. Hard to argue with going with what's worked for years, but even relays can die early with too high of temps for too long.


True, but you don't have to worry about getting replacement components 10 years down the road.
 
True, but you don't have to worry about getting replacement components 10 years down the road.

Good point, as long as he's sticking with standard form factor and design relays. But if he's using some special high temp or timer/ multifunction relays, he may have the same problem.
 
Remove the heat-generating equipment from the panel.

One prime candidate is a control voltage transformer, e.g. from 400V to 230V. These things generate a lot of heat. Instead, design the control panel for 3-phase AC for power, and 24 VDC for control.
For the 24 VDC no transformer, just a 3-phase-to-24VDC PSU.

If you have VFDs, then maybe try to find a version with the heat-sink being mounted in a cut-out in the panel, so that the electronics are on the inside but the heatsink is on the outside. "push-through" as I think it is called.
edit: And brake resistors go on the outside of the panels as well.

The PLCs themselves used to generate heat a lot (lay your hand on the chassis of an SLC500 for example), but current tech PLCs are all cool to the touch, or luke-warm at worst.
 

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