JLD612 & PT100 with SSR

[jsigup]

I need some help. I have tried to setup the JLD-612 PID controller with a PT100 probe and an external SSR (solid-state relay), but the display shows "EEEE" after programming the controller.

Intended Use:
I want the PID controller to initially provide low voltage DC power to the SSR input so the SSR will closed and allow 120VAC power to energize a heater element until an upper temp limit of 130 F is achieved in a fluid. At that time I want the PID controller to switch power off to the SSR input until a lower temp limit of 80 F is achieved. At that time I want the PID controller to switch the low voltage DC power back on to the SSR input. I want this on-off switching to continuously loop until I manually shutdown the system.

PID Connections:
1. Power = 120 VAC connected to PID controller terminal screws 1&2
2. SSR = low voltage DC input connect to PID ctrller terminal screws 6 & 7
3. Probe = pt100 colored wires connected to terminal screws: RD=8, BL=9, BL=10 (RD=red, BL=Blue)

Ohm measurements show the following: .8 ohms across the 2 BL wires. Open between the RD wire and either BL wire, I assume the PT100 probe has a thermistor in it, so I guess the thermistor is wired in series between the BL wires and that explains the .8 ohms measurement. Is it possible the 2 blue wires should be reverses on terminal screws 9 & 10. I doubt it, but I think it is probably worth asking, just to be thorough.

PID Controller Setup Procedure:

1. Initialization parameters settings
â—‹ Entered 0089 programing mode
â—‹ Set or verified the following parameters:
â—‹ IntY = pt 100
â—‹ OutY = 2
â—‹ HY = 0.3
â—‹ Psb = 0
â—‹ Rd = 0
â—‹ C or F = 1
After exiting programing mode,
• Upper PID controller display (PV) shows "EEEE"
• Lower PID controller display (SV) shows "130"

2. Temperature and Alarm parameter setting mode
â—‹ Entered 0001 programing mode
â—‹ Set or verified the following parameters:
â—‹ Sv = 130
â—‹ AH1 = 130
â—‹ AL1 = 130
â—‹ AH 2 = 80
â—‹ AL 2 = 80

After exiting programing mode,
• Upper PID controller display (PV) shows "EEEE"
• Lower PID controller display (SV) shows "130"

3. Initiated auto tuning by pressing "Set" and ">" button simultaneously

• This cause the "AT" LED to light up
• Upper PID controller display (PV) still shows "EEEE"
• Lower PID controller display (SV) still shows "130"

4. I tried some IntY setting options - room temp = 79F
Below is the value shown as PV
â—‹ Pt 100 = EEEE
â—‹ Pt 10.0 = EEE.E
â—‹ K = 90
â—‹ E = 90

Did I connect something incorrectly?? Did I forget program something?? Is the PID malfunctioning?? Is the probe defective??

Does anyone have any idea what I can do next to make this thing work??

Thanks in advance.

[richiem]

The first and most serious problem is that the Pt100 probe is open -- the resistance between the red wire and either blue wire should be around 105-110 ohms at room temp, and you should see essentially a dead short between the blue wires, depending on the length of the cable and the gauge of the wires -- 8 ohms seems a bit high to me. Strike that -- just saw that there was no leading zero on the ohms, which you posted as .8 and I read as 8 -- so the blue wires are just fine.

The probe is not a thermistor in the precise sense -- it is a platinum sensor that has a resistance of 100 ohms at 0 deg C/32 deg F, (why it's called Pt for platinum and 100 for the 0 deg C resistance) and will be about 135 ohms at 100 deg C/212 deg F.

I haven't had a chance to look over your settings, but you'll get errors galore with an open probe.

I'll say more after I've had a chance to review your settings and application. Just wanted to give you the heads up on the probe.



OK, I would use the Pt10.0 setting for best precision. Read the Manual and Tech_Marco's explanations of using the Hy (hysteresis) mode to set the controller to work like a regular thermostat but with a very large dead band (80 deg on, 130 deg off). You do not want to use PID control for this application, so auto-tuning won't do anything for you.

The alarm settings are usually just used to provide an over or under temp warning via a light or horn; again, read the manual carefully to see the options available to you. For this application, the only thing the probe and the controller will do for you is to precisely set the on temp and the off temp, plus giving you the very large temp gap between them.

[msfigaro]

Hi Richiem,

Thanks for responding to my post.

I retested the probe & it is still open across the RD wire & either BL wire. It looks as though I will need to return the probe for a good probe to resolve that problem. Thanks for the "pt10.0" setting suggestion. That setting should provide a more precise display value.

Can you provide me with a url to "...Tech_Marco's explanations of using the Hy (hysteresis) mode to set the controller to work like a regular thermostat..."? I searched this website & I have not seen anything like what you have described?

I have reviewed the PID controller manual again. I find nothing in it of any benefit regarding the hy mode configuration as it pertains to my intended application. Frankly, I find the PID controller manual to be badly written. I see in the manual that one of the diagrams shows the input side of the SSR is to be connected to the PID controller SSR output using terminal screws 6 & 7. I do not see anything in the manual that clearly specifies the PID controller SSR output current type (AC/DC) and voltage, its intial state, and which events de/energized it. I need it on until my heated fluid temp is 130 F, then switched off until the fluid temp is 80 F, then looped until I manually disable the system. The only thing that I can be sure of at this point is the SSR label shows a minimum of 3 vdc is required to energize the SSR; but, I see nothing in the manual to indicate which "hy" parameter/s and/or other parameter/s to set in the PID controller to make the PID controller control my heater as previously described.

Assuming I connect a functional probe to the PID controller, do you know where I can find a simple step-by-step PID programming procedure for the simple application that I'm trying to setup? A good theory of operation document for the JLD612 would be quite useful too. Why the manufacture of JLD612 doesn't have a setup procedure for each mode of operation for such a simple device is quite unimpressive, imo.

Thanks in advance

[richiem]

Yeah, the manual is not good, but it is all there. They assume some familiarity with industrial control systems which is what this controller is designed for. Be sure to download the 2011 dated manual from the lightobject manuals page. I'll refer to that manual and its information.

The manual specs page show the SSR output as a current source with an open circuit voltage of 6 VDC -- it's probably actually 8 VDC --, and a short-circuit current output of 40mA. This will drive any DC controlled SSR that I've seen on the market. Correct connection polarity is essential -- PID controller SSR output + to SSR input +.

Be sure to set temp setting to Fahrenheit, not Celsius. Set output mode to heating. Set probe type to Pt10.0. Ignore the various alarm settings, you don't need to do anything with them at all.

See the bottom of page 3 for the numbered notes -- you want to use the note 3 config, with diagram in Fig 3 on the next page. Use the left side of figure 3 (heating), where the output of the SSR is on (latched) when the actual temp is below your lower limit (SV-HY), and stays on until it reaches the upper limit (SV). So, set SV to 130, and set HY to 5.0 (ignore the decimal point). When the PV (present value being read by the probe) is less than 80 deg, the SSR is on and heating occurs. Heating stops at 130 deg, and stays off until the PV is again less than 80 deg.

Try it out with water first to be sure you've got everything set correctly.

Hope this helps.

[msfigaro]

Hi Richiem,

Thanks again for responding to my post.

I am still waiting for the new probe to arrive. I will try what you have recommended when the probe arrives.

In the mean time, I tested the PID controller output voltage on terminal screws 6 &7. My meter showed 0 VDC & 8 VAC. An AC output seems a bit odd since the SSR input requires DC. I guess the AC *may* work to drive the coil in the SSR, if the current is high enough. What do you think?

I also looked again at the JLD612 (2011) manual and I do not see any reference to what the hy (hysteresis) setting does (i.e. how various values affect the controller's functioning). I know you have recommended that I use a setting of 5 and I see in the manual that the hy range is 0 to 9999, so what you've recommend is feasible, but I do not see any details in the manual that explain what that setting does exactly.

I also reviewed the heating mode notes on the bottom of page 3 and the "heating" graph in "Fig. 3" on page 4. Based on what you have typed & what I see in the manual, I am a bit puzzled. The graph seems to indicate that the probe temp (i.e. PV) initially rises when PV is below my lower & upper limit temps (i.e. 80F & 130F, respectively). That makes sense to me as the initial heating should continue until my upper temp limit of 130 F is realized by the PID controller. At that time, the PID controller should switch off power to terminal screws 6 & 7.

What is a bit puzzling is that the "heating" graph in "Fig. 3" shows the PV continues to rise beyond the SV (i.e. into the unlatched region of the graph) for what appears to be about 1/3 of the unlatched state (i.e. when there is an open circuit (power is off) on PID controller terminal screws 6 & 7). It also shows that after the lower temp limit (i.e. SV-HY) is reached, the PV continues to fall for about 1/3 of the 2nd "latched" state before it begins to rise again. Is there some kind of time delay before the power is switched off and on to terminal screws 6 & 7? Also, if SV-HY = 130 F - 5 = 125, how does 125 cause power to be restored on terminal screws 6 & 7 so the heater will energize--125 is much higher than 80 F? Does a hy setting of "5" = 5 * 10 F = 50 F, so that 130 F - 50 F = 80 F?

One last item. You typed "See the bottom of page 3 for the numbered notes -- you want to use the note 3 config,...". By "note 3" do you mean the 3rd note (i.e.: "2: Relay J1 and J2 as alarm outputs; SSR PID output 8V SSR signal. Target: SV" or actually note 3 (i.e. "3. J1, J2 alarm output; differential control by SSR. See Fig 3")?
It appears to me that note "2" is the correct note for my application.

Thanks in advance.

[richiem]

[quote="msfigaro"]

In the mean time, I tested the PID controller output voltage on terminal screws 6 &7. My meter showed 0 VDC & 8 VAC. An AC output seems a bit odd since the SSR input requires DC. I guess the AC *may* work to drive the coil in the SSR, if the current is high enough. What do you think?

This is worrisome -- the SSR output is supposed to be DC. I think that either this controller does not supply a DC control output for the SSR, or something is wrong, or perhaps you misread the meter settings. What was the AC voltage on the output? Note that SSRs are totally solid-state -- there are no coils in them.

I also looked again at the JLD612 (2011) manual and I do not see any reference to what the hy (hysteresis) setting does (i.e. how various values affect the controller's functioning). I know you have recommended that I use a setting of 5 and I see in the manual that the hy range is 0 to 9999, so what you've recommend is feasible, but I do not see any details in the manual that explain what that setting does exactly.

I recommended a setting of 50, which appears in the display as 5.0, which is completely counter-intuitive, and is why I said to ignore the decimal point. Your application requires a hysteresis of 50 degrees -- 130 -80 = 50. Unfortunately, the only detail about the Hy function in the manual is Figure 3. But at least it does show how it works.
....
What is a bit puzzling is that the "heating" graph in "Fig. 3" shows the PV continues to rise beyond the SV (i.e. into the unlatched region of the graph) for what appears to be about 1/3 of the unlatched state (i.e. when there is an open circuit (power is off) on PID controller terminal screws 6 & 7). It also shows that after the lower temp limit (i.e. SV-HY) is reached, the PV continues to fall for about 1/3 of the 2nd "latched" state before it begins to rise again. Is there some kind of time delay before the power is switched off and on to terminal screws 6 & 7? Also, if SV-HY = 130 F - 5 = 125, how does 125 cause power to be restored on terminal screws 6 & 7 so the heater will energize--125 is much higher than 80 F? Does a hy setting of "5" = 5 * 10 F = 50 F, so that 130 F - 50 F = 80 F?

See previous clarification about the hysteresis value, above. As to the diagram, it isn't meant to be taken too literally -- when your heater turns off, it probably won't have sufficient thermal mass to keep on heating the solution very much if at all, so your system will essentially peak at the turn-off point, then start to cool off. Likewise for the lower limit -- as the solution cools, when the heater turns on, the solution will start to heat up more or less immediately, with little or no undershoot. If it turns out that there is a lot of undershoot, you may need a larger heater....

One last item. You typed "See the bottom of page 3 for the numbered notes -- you want to use the note 3 config,...". By "note 3" do you mean the 3rd note (i.e.: "2: Relay J1 and J2 as alarm outputs; SSR PID output 8V SSR signal. Target: SV" or actually note 3 (i.e. "3. J1, J2 alarm output; differential control by SSR. See Fig 3")?
It appears to me that note "2" is the correct note for my application.

The notes are numbered 0 thru 4. Note number 2 is for using the "fuzzy logic" PID control system -- but you aren't using the PID system, you just want an accurate thermostat with hysteresis. As I understand it, note number 3 is the correct setup, since that note refers specifically to Figure 3, which shows the hysteresis mode in action.

But nothing beats trying something else if number 3 doesn't work. I've never used the hysteresis function myself, so I have no direct experience with it. Good luck.

[jsigup]

I finally got a chance to get back to setting up the PID controller with the new probe attached. Below are the final settings that I used:

1. Initialization parameters settings:
â—‹ Entered 0089 programing mode
â—‹ Set or verified the following parameters:
â—‹ IntY = pt10.0
â—‹ OutY = 3
â—‹ HY = 46.0 Note: My final upper temp limit = 130 F. My lower temp limit = 84 F. Since 130-84 = 46, the HY parameter must be set 46 to work for my application
â—‹ Psb = 0
â—‹ Rd = 0
â—‹ C or F = 1

After exiting programing mode,
• The upper PID controller display (PV) showed "78.2"
• The lower PID controller display (SV) showed "130.0"

2. Temperature and Alarm parameter setting mode:
â—‹ Entered 0001 programing mode
â—‹ Set or verified the following parameters:
â—‹ Sv = 130.0
â—‹ AH1 = set as default value, since it isn't needed for this application
â—‹ AL1 = set as default value, since it isn't needed for this application
â—‹ AH 2 = set as default value, since it isn't needed for this application
â—‹ AL 2 = set as default value, since it isn't needed for this application

I tested the setup with hot & cold water & it functioned perfectly!

Thank you, richiem for your help! I couldn't have figured this out without your help.

I hope this information will be useful to others who have problems understanding the JLD-612 PID controller manual.

[richiem]

So just to confirm, the Hy = 46.0 worked OK for the lower limit, with IntY = pT10.0? It actually is a 46 degree difference? If so, as Marco said it is in another post, that's important info and will help me a lot in my own setup.

[jsigup]

So just to confirm, the Hy = 46.0 worked OK for the lower limit, with IntY = pT10.0? It actually is a 46 degree difference? If so, as Marco said it is in another post, that's important info and will help me a lot in my own setup.

Sorry I didn't respond to your last question. As I stated in my previous posting, the system seemed to work "perfectly". I used an analog thermometer (not as precise as a digital thermometer), but it seemed to be dead-on for the high & low temp limits of my application.

Thanks again for your help!