I just ordered a blanket and I am in the process of gathering everything up to make a controller.
I will be honest, I have a lot to learn as far as electronics go... I think I have found a PID controller however it only has a linear DC output. Will this work with a SSR as described in the article on this website?
Heat Blanket
Moderators: Head Monkey, kelvin, bigKam, skidesmond, chrismp
I'm no electronic whiz myself, but, I believe that most SSR's use DC voltage as the control input. All of the relays that I've seen say right on their face what the input voltage is... 3 to 32 VDC is a very common rating. The output rating is designated in amps... you'll want to calculate your heat blanket's load rating to make sure that your SSR can handle it. A 10 amp rating can be borderline. 20 amps is probably enough to handle most any ski press heater (watts / volts = amps). Regarding your PID, they can be pretty intimidating, and many are sold without operating instructions. I'd suggest that you try real hard to get the instructions for the unit that you are getting.
One more thing... SSR's are generally attached to a 'heat sink' that helps to disapate the heat that they generate. Most SSR's that I've seen aren't sold with the heat sink attached. Also, the heat sink should be attached with a 'thermal grease' between the SSR and heat sink (helps with heat conduction). You may find an SSR (new or used) that appears to be a good deal, but, after buying the heat sink and the thermal grease (as much as $50 more), the deal starts to not look so good, especially if it's a used unit (like from ebay). Grainger sells a complete new 10 amp unit for around $50. I already had some thermal grease, and I had 1/2" x 6" x 8" piece of aluminum laying around the shop. I attached the SSR to the aluminum and used it as the back of my control box. The aluminum has so much mass, it never even gets warm. Good luck.
G-man
One more thing... SSR's are generally attached to a 'heat sink' that helps to disapate the heat that they generate. Most SSR's that I've seen aren't sold with the heat sink attached. Also, the heat sink should be attached with a 'thermal grease' between the SSR and heat sink (helps with heat conduction). You may find an SSR (new or used) that appears to be a good deal, but, after buying the heat sink and the thermal grease (as much as $50 more), the deal starts to not look so good, especially if it's a used unit (like from ebay). Grainger sells a complete new 10 amp unit for around $50. I already had some thermal grease, and I had 1/2" x 6" x 8" piece of aluminum laying around the shop. I attached the SSR to the aluminum and used it as the back of my control box. The aluminum has so much mass, it never even gets warm. Good luck.
G-man
As to scrounging heat sinks... 
I don't know how big your SSR is but you could take apart an old computer and pull the fan/heatsink off the processor. The fan runs on either 5 or 12 volts, so you could run it on a couple AAs or a 9 volt or some AC/DC power cord from something you have lying around. And these heatsinks/fans were meant to dissapate maybe 50-75 watts of heat, so you should have no problem. Thermal paste can be found at a CompUSA or similar store.
Good luck.
I don't know how big your SSR is but you could take apart an old computer and pull the fan/heatsink off the processor. The fan runs on either 5 or 12 volts, so you could run it on a couple AAs or a 9 volt or some AC/DC power cord from something you have lying around. And these heatsinks/fans were meant to dissapate maybe 50-75 watts of heat, so you should have no problem. Thermal paste can be found at a CompUSA or similar store.
Good luck.
------------------Take nothing I say as expert advice------------------
Linear DC output refers to a voltage or current that is proportional to the amount of power you need. In order to use this controller, you will need a SCR (silicon controlled rectifier). Sometimes it is called analog output.
To use a SSR, you need a controller with a DC voltage pulse output. This is either on or off and controls the power by the varying the amount of time that it is on.
Either one will work, but a SSR is usually cheaper and more than adequate for our purposes. In the article, I use a SSR. For a more detailed explanation, here is a good article:
http://www.omega.com/temperature/Z/pdf/z110-114.pdf
If you are buying from ebay or similar, be sure you get the EXACT part number, then look up that part number from the manufacturer's website. Since there are usually hundreds of different configurations of the same model controller, the only way to be sure what you are getting is to download the datasheet and decipher the part number code.
Heat sinking is important if you are running at rated capactiy, but without one the capacity is usually around 50%. So if you get a big enough SSR you can skip the heat sink, or just attach it to the metal enclosure. I'm only using about 50% on my SSR, but it came with a heat sink.
-kelvin
To use a SSR, you need a controller with a DC voltage pulse output. This is either on or off and controls the power by the varying the amount of time that it is on.
Either one will work, but a SSR is usually cheaper and more than adequate for our purposes. In the article, I use a SSR. For a more detailed explanation, here is a good article:
http://www.omega.com/temperature/Z/pdf/z110-114.pdf
If you are buying from ebay or similar, be sure you get the EXACT part number, then look up that part number from the manufacturer's website. Since there are usually hundreds of different configurations of the same model controller, the only way to be sure what you are getting is to download the datasheet and decipher the part number code.
Heat sinking is important if you are running at rated capactiy, but without one the capacity is usually around 50%. So if you get a big enough SSR you can skip the heat sink, or just attach it to the metal enclosure. I'm only using about 50% on my SSR, but it came with a heat sink.
-kelvin
So if I have a controller that sends out an AC relay signal...i should find an SSR that has an AC input and output? is there a benefit to having a DC signal over an AC signal? I recently purchased the Omron E5CJ and an SSR with DC input, AC output. the problem is that when i went to wire everything, the side of the controller said that it sent a 3A, 250AC signal, not the 12DC signal i suspected. so now i dont know if there is something i am misunderstanding, or if i need to replace either the SSR (with an AC in, AC out SSR), or if I should replace the controller with a DC output. any advice would be greatly appreciated as the blanket should be arriving any day now, and i already have a couple custom board orders to fill!
Hey mattman,
I just did a little checking on:
www.grainger.com/Grainger/wwg/productIn ... +Relays%2C
They have SSR's with AC input/AC output. It almost sounds like the PID controller that you have requires a 220v input, rather than 110v. It also looks like most of the AC input SSR's on the Grainger site have a 220v output. So, I'm just wondering if maybe the AC output PID controllers are more intended for situations where 220v power sources are used, both for the PID input and for the switching side of the SSR. I don't really know, though... I was actually surprised to find that AC input SSR's even existed.
But, in terms of your present situation, it looks like your PID controller and your SSR are not compatible. You can get a new DC output controller for about 50 bucks, or you can get an AC input SSR for about the same. If you don't want to have to deal with 220v supply current, I'd say go with the DC output controller.
Does your AC output controller require a 220v input? I'm curious to know.
G-man
I just did a little checking on:
www.grainger.com/Grainger/wwg/productIn ... +Relays%2C
They have SSR's with AC input/AC output. It almost sounds like the PID controller that you have requires a 220v input, rather than 110v. It also looks like most of the AC input SSR's on the Grainger site have a 220v output. So, I'm just wondering if maybe the AC output PID controllers are more intended for situations where 220v power sources are used, both for the PID input and for the switching side of the SSR. I don't really know, though... I was actually surprised to find that AC input SSR's even existed.
But, in terms of your present situation, it looks like your PID controller and your SSR are not compatible. You can get a new DC output controller for about 50 bucks, or you can get an AC input SSR for about the same. If you don't want to have to deal with 220v supply current, I'd say go with the DC output controller.
Does your AC output controller require a 220v input? I'm curious to know.
G-man
first off, thanks for the fast help!! my controller says that its supply voltage is 100 to 240...yet it says that its relay signal is 3A, 250V...the only DC output that it has is the "Voltage control" which is 20mA at 12V DC...but i am assuming that is the wrong output for SSRs. I do not want a 110V controller, because I intend to run a 240V blanket and its temp controller off the same power source (very similar circuit to the skibuilder's article). I just dont want multiple cords. I can pick up a new SSR with both sides rated to 240 AC for under 20 on ebay...so if there is no reason that a DC signal is better, I will do that. any other thoughts i should keep in mind before buying? again, thanks for the help.
mattman,
After reading your last post, I happened to remember that I had a back-up PID controller in a drawer right next to my computer. I pulled out the spec sheet that I had downloaded when I got the controller, and what do you know, the sheet said that mine had a 'relay contact volume' of AC220V/3A. My first thought was that "dang, I screwed up and bought the wrong controller... now I have to buy an AC SSR". Then, I got on ebay to see if the controller was still available so that I could see how I managed to net see that it was an AC controller. It is still available (the VTC-620), but the specs listed didn't say anything about the output voltage. Then I clicked on another model, and its spec sheet said:
Output mode
Relay contact: 3A@240VAC, SSR: 10VDC, 40 mA.
Here's the page:
http://cgi.ebay.com/UNIVERSAL-PID-TEMPE ... dZViewItem
So, I'm kinda thinking that these controllers may have both AC and DC outputs. If so, your controller may work fine with a DC input SSR. I need to do some more research, but it's late and I'm getting too blurry eyed to do it tonight. I just wanted to catch you before you ordered another controller that maybe you don't need. I think that I need to check out the controller that I have on my press at my shop (10 miles away, in town) and see what the spec sheet says about it's control output. If it says tht there is an AC option, we're in the clear because I'm running a DC input SSR off of it. I'll probably be going by the shop tomorrow and I'll let you know what I find out.
I don't know where these controllers come from that are sold on ebay. They seem to work fine, and the price is right, but the spec info always seems to be on the slim side.
G-man
After reading your last post, I happened to remember that I had a back-up PID controller in a drawer right next to my computer. I pulled out the spec sheet that I had downloaded when I got the controller, and what do you know, the sheet said that mine had a 'relay contact volume' of AC220V/3A. My first thought was that "dang, I screwed up and bought the wrong controller... now I have to buy an AC SSR". Then, I got on ebay to see if the controller was still available so that I could see how I managed to net see that it was an AC controller. It is still available (the VTC-620), but the specs listed didn't say anything about the output voltage. Then I clicked on another model, and its spec sheet said:
Output mode
Relay contact: 3A@240VAC, SSR: 10VDC, 40 mA.
Here's the page:
http://cgi.ebay.com/UNIVERSAL-PID-TEMPE ... dZViewItem
So, I'm kinda thinking that these controllers may have both AC and DC outputs. If so, your controller may work fine with a DC input SSR. I need to do some more research, but it's late and I'm getting too blurry eyed to do it tonight. I just wanted to catch you before you ordered another controller that maybe you don't need. I think that I need to check out the controller that I have on my press at my shop (10 miles away, in town) and see what the spec sheet says about it's control output. If it says tht there is an AC option, we're in the clear because I'm running a DC input SSR off of it. I'll probably be going by the shop tomorrow and I'll let you know what I find out.
I don't know where these controllers come from that are sold on ebay. They seem to work fine, and the price is right, but the spec info always seems to be on the slim side.
G-man
Back again,
Okay, I think I've got it. My PID controllers can be used for either a mechanical relay (with contact points, like a mercury switch) or with a solid state relay (no moving parts). A mechanical relay (connects to the J1 or J2 terminals on the PID unit) requires AC current from the controller. A solid state relay (connects to the SSR terminals on the PID unit) requires DC current from the controller. I'm betting that your controller isn't too much different from mine... it seem that most of the controllers offered on ebay have the same configurations (you can check out the terminal diagrams for them by clicking on them). When you see "relay output" or "relay contact output", they are talking about the output for a mechanical relay, not a SSR. The spec info often doesn't specifically mention the DC output for the SSR, even though the option is there. So, I think that you are okay with what you have for running a DC input SSR. Maybe someone that knows more about this stuff than I do will chime in.
G-man
Okay, I think I've got it. My PID controllers can be used for either a mechanical relay (with contact points, like a mercury switch) or with a solid state relay (no moving parts). A mechanical relay (connects to the J1 or J2 terminals on the PID unit) requires AC current from the controller. A solid state relay (connects to the SSR terminals on the PID unit) requires DC current from the controller. I'm betting that your controller isn't too much different from mine... it seem that most of the controllers offered on ebay have the same configurations (you can check out the terminal diagrams for them by clicking on them). When you see "relay output" or "relay contact output", they are talking about the output for a mechanical relay, not a SSR. The spec info often doesn't specifically mention the DC output for the SSR, even though the option is there. So, I think that you are okay with what you have for running a DC input SSR. Maybe someone that knows more about this stuff than I do will chime in.
G-man
I found the PDF instruction manual for the PID controller that I have been using on my press. I tried to attach it to this post, but I couldn't figure ot how to do it. Anyway, the specification section of the manual only lists a voltage/amperage value for the contact relay mode (just like the specs on the other PID's on ebay) . That value is 220v/3A. It does not say what the SSR voltage/amperage output is, but it certainly works fine with my SSR. So, this seems to confirm my hunches stated in my last post. I'd suggest that, when you get your heat blanket, you lay all of your stuff out on the kitchen table, wire it up, flip on the power switch and see if your blanket heats up. I bet it works just fine and you won't have to purchase any other parts.
G-man
G-man
do you use the same two connections on the back of your controller as you would for any other output? (9 and 10 on mine).
I think i am going to take your advice and wait to see if the setup works...worst case scenerio i kill an SSR that i would have to replace anyway! it is reassuring to hear that your manual says the SAME THING as mine and your DC ssr works just fine. thanks!
I think i am going to take your advice and wait to see if the setup works...worst case scenerio i kill an SSR that i would have to replace anyway! it is reassuring to hear that your manual says the SAME THING as mine and your DC ssr works just fine. thanks!
mattman,
Here's a page from ebay that shows the terminal connections for the same PID as I have on my press:
http://cgi.ebay.com/Universal-Digital-P ... dZViewItem
Yes, I use terminals 9 & 10 for DC output to the SSR. On this controller, one would use terminals 4 & 5 (J1 output) for a contact relay connection (a mechanical relay like a mercury switch). Terminals 4 & 5 would have an AC output of 220V/3A.
I have learned a lot here, also. Let us know how your test assembly works.
G-man
Here's a page from ebay that shows the terminal connections for the same PID as I have on my press:
http://cgi.ebay.com/Universal-Digital-P ... dZViewItem
Yes, I use terminals 9 & 10 for DC output to the SSR. On this controller, one would use terminals 4 & 5 (J1 output) for a contact relay connection (a mechanical relay like a mercury switch). Terminals 4 & 5 would have an AC output of 220V/3A.
I have learned a lot here, also. Let us know how your test assembly works.
G-man
It looks like you guys are talking about 2 different controllers here. The controller that Gman has looks like it has 2 outputs. The e5cj normally has 1 output, but can be ordered with 2 outputs.
mattman, what is the part number of the controller you have? The 3A, 250vac refers to the maximum power that the internal relay can handle. If your heater was small enough, you could connect it directly to the controller, with no additonal relay. Most likely your blanket will use more power, and you will need an external relay (mechanical or solid state). Hooking up your dc ssr to this output most likely won't do anything. The relay outputs do not supply any power, it is basically just a switch.
As a side note, you can run 110v stuff off a 220 plug as long as it is a 4 wire plug (look at your dryer plug). There are 2 hot wires, a neutral, and a ground. If you hook up one hot wire and neutral, you have 110. 3 wire plugs leave out the neutral so you can't do this.
-kelvin
mattman, what is the part number of the controller you have? The 3A, 250vac refers to the maximum power that the internal relay can handle. If your heater was small enough, you could connect it directly to the controller, with no additonal relay. Most likely your blanket will use more power, and you will need an external relay (mechanical or solid state). Hooking up your dc ssr to this output most likely won't do anything. The relay outputs do not supply any power, it is basically just a switch.
As a side note, you can run 110v stuff off a 220 plug as long as it is a 4 wire plug (look at your dryer plug). There are 2 hot wires, a neutral, and a ground. If you hook up one hot wire and neutral, you have 110. 3 wire plugs leave out the neutral so you can't do this.
-kelvin
my controller is the omron e5cj-R2-F it was my understanding that the conroller outputs sent out a signal that was recieved by the ssr. when this signal was sent through one side of the relay, the other side of the relay closed the heat blanket circuit. i know that the "R2" part of the name refers to "relay" and "2 alarms". if its referring to the wrong kind of relay, what kind is it? my blanket will be 2300V (ish) so that I can use 10amp switches on a 240V line. i am really not sure what to buy now and i havent had much luck getting a hold of omron's tech support