REX C100 wiring
Hi there folks,
Nearly finished building the extruder but am having issues with my wiring. Have followed the wiring diagram for logic and wired everything up. I have 2 REX C100’s and 4 heating elements, all wired the same as Dave’s (1 REX c100 for 1 heating element at front and another REX c100 for 3 at the back). The one at the front works fine but the three at the back connected together don’t seem to be working.
Has anyone else encountered this and does anyone have any solutions? Should I be wiring all three thermistors to the 1 REX c100 or should I just be wiring 1 in?
Thanks in advance! So close to having this guy working!
Each PID should have it’s own thermocouple and its own heating element(s). Wiring the same thermocouple to multiple PIDs defies the purpose of having multiple PIDs for fine tuning the temps.
If one of your PIDs is working fine, I assume you wired something incorrectly in the other 3. I can’t tell what could be wrong without pictures, but I suggest making sure that you wired the SSR relay with the right polarity. If you invert the SSR polarity, it won’t turn on.
What Olivier said.
Also, you said thermistor, did you mean thermocouple? I think the sensor hookup for resistance thermometers is a little different from the thermocouple models.
When you say not working, what does that mean? Does the PID show a reasonable PV temperature? When you set the temperature higher, does the output light come on? Does your PID output match the SSR (low voltage signal) etc.
Yeah, some pictures or symptoms will help
Thanks for the replies – to clarify, I have two REX c100’s (or two PID’s), each with a thermocouple and four heating elements total. the front heating element is connected to to 1 PID and the other 3 heating elements are connected to the other PID.
I had extra thermocouples and had wondered whether the PID could take a combined reading of all three heating elements but I will keep it simple and just connect 1. Therefore I have the following:
– PID connected to 1 heating element & 1 thermocouple
– PID connected to 3 heating elements & 1 thermocouple
The first works but the PID connected to three heating elements does not. Both wired exactly the same with the heating elements wired in parallel. Have uploaded an image of the PIDs – you can see the lower one is climbing (connected to one heating element) whilst the second can read temperature but does not heat the element.
What wattage is each of the 3 bandheaters? Are you using a SSR or relay output? You may be trying to draw too much current and have burnt something out. Note that the cheapo SSRs can’t cope with the current they are supposedly rated for, so play it safe. If you swap the connections does the PID for the 3x heaters work on the single one?
They are 200W bandheaters, so 600W together? Using a cheap SSR (states 40A) and I had wondered whether I was drawing too much current but the current draw of all three bandheaters together at 230V would only be 2.6A I think? I have a very basic understanding of electronics so forgive me if my calcs are way off!
Will try and swap the connections to see if its the SSR or PID maybe – great tip.
Thanks again folks! Hope I can get this up and running.
Having tried another SSR, I am having the same issue. the indicator LED for both SSR’s is on, so it looks like it’s getting power and a signal to turn on?
I would start taking some measurements with a multimeter.
– Confirm that both PID’s are producing the right output that matches what the SSR needs (the PIDs look identical but have different dash numbers for the different type)
– Confirm you got mains power coming to the SSR and check whether it switches on.
– Check continuity in your heater loop
– Check that your thermocouple is mounted with the tip pressed against the tube.
You’ve probably done many of these, just a check list
You must be logged in to reply to this topic.