Sign up

[LaneLearning]

I am setting up an SYL-2352P for the first time.  I'm no PID programing expert and am having a problem.  The ramp function appears to be bypassed by the Safety Start feature.  I want to use the ramp function and need to understand how to turn off the Safety Start. I've attached a diagram of my schematic (that includes another unrelated circuit.  My SYL-2352P circuit is working...  I just can't get the ramp function working.  I should correctly say that the ramp is working, but at full on power. I want to be able to slow ramp based on a set time i prescribe in the settings rather than only being limited by how fast my heating element can ramp up at 240V. 

I've tried different combinations of Hy-1 and Hy-2 (typically something like 3), and Hy (typically something like 2).  Here is a very simple program I'm trying to get the ramp function working on. 
C1 = 90, T1 = 1 (ambient is typically at 60 or so.  and my heating coil heats very quickly, so this gets it to 90 quickly)
C2 = 90, T2 = 1 (just to sit for a minute to give me time to watch it)
C3 = 350, T3 = 15
C4 = 350, T4 = -121

No matter whether I set T3 for 15 or 120 (or I presume any other value), the controller sends 240V to my heating coil and it ramps up at maximum speed with the Hy-2 intermittently flashing in the bottom window of the controller. 

I'm sure it's probably something I'm doing wrong...  hope so anyway so that I can fix it.  Thanks for any ideas on how to get this ramping program ramping at a slow speed i set! 

[Kkane]

Well, by the default settings, safety start is disabled (Hy-1 = 9999, Hy-2 = 9999, Hy=0.3).  Please be advised, the output signal from the controller is time proportional ON/OFF. When there is an output, it is 100% ON. When there is no output, it is 0% OFF. If the current output is 10% and if your cycle time is 10s, it means the output will be ON for 1s and OFF for 9s. So the average power output for 10s is 10%.

Your program looks incorrect. Here is the explanation for your program:

C1 = 90, T1 = 1 //hold at 90 (change from C1 to C2) for 1 minute (T1)
C2 = 90, T2 = 1 //ramp up from 90 (C2) to 350 (C3) in 1 minute (T2)
C3 = 350, T3 = 15 //hold at 350 for 15 minutes
C4 = 350, T4 = -121 //stop

Hy-1 and Hy-2 are functional for the derivation alarm and safety start feature. Safety start means, in a specific ramp step, when the time is up but your temperature difference between your reading temperature and set temperature is different than the derivation value (decided by Hy-1, Hy-2), the timer will be on hold.

If you have a hard time to maintain at 350F, you can consider processing auto-tune at 350F. You can use the following program to run auto-tune:

C01 = 350, t01 = 1
C02 = 350, T02 = 0

Auto-tune will optimize your control based on your temperature and on your oven. You should have better control than before.

The bottom line is, if your system is extremely fast acting (like only taking a couple seconds to heat up from 90 to 350), it might be difficult for the PID to control, since the overshoot/undershoot issue is likely to happen. You may need to consider using a smaller heating element.

====

The following reply is for your attached drawing. Your system could be more complicated than I thought. So you have two elements. One is controlled by our PID. Another is controlled by a SSVR with potentiometer. It is not recommended to use two control systems for a single oven, since two systems will conflict with each other. If you don't adjust your top heating element (the position for the potentiometer is unchanged), it will be easier for the PID to control the bottom heater. If you are always adjusting the power for your top heating element, it will be hard for the PID to adjust the temperature. In that case, you may consider using one PID to drive two SSRs, each SSR drives each element (not using SSVR for the top heater)

[LaneLearning]

Thanks KKane,

The complexity of the circuit is misleading.  I set up the second heating element in the event that I needed a really low level heat source to maintain temperature.  Turns out that I don't need the second heating element controlled by that SSVR w pot.  The PID controlled element is clearly more than enough heating engine. 

I have tried the Hy-1 and Hy-2 setting at 9999 with the Hy=0.3.  it did get rid of the Hy-2 flashing.  But the ramping is still taking place at 100 percent of the 240V source voltage.  This is even when I set up a very slow ramping time like 1 hour.  Instead of taking an hour to ramp up, mine ramps up like a rocket.  My heating coil can heat from room ambient to 400F in about 4 minutes.  But I want to be able to use a slow ramp to ramp from ambient (~65F) to 400F or so in a very linear fashion over perhaps 1 hour or so.  I thought this SYL-2352P could do that and am still hopeful it can and I just need to learn how to do it. 

I could use the OUTH (output high limit) at a lower percentage than 100% and indeed have the controller take longer to ramp up the heating element.  But I would rather use the ramp function of the controller to precisely alter the time proportional output as you mention to do that ramp using ramping time.  Right now, even using Hy-1 = 9999, Hy-2 = 9999, Hy=0.3, my controller is delivering 100% of 240V to my heating element during the ramp up phase, regardless of how long I set the ramp up time. 

BTW, I agree with you that using autotune is helpful.  I've tried it in several different situations with this SYL-2352P and it does help the steady state stability.  The PID function is great...  I just need to figure out how to get the controller to ramp up slowly rather than constantly delivering 240V to my controller during ramping phase. 

Appreciate any insight you have. 

[Kkane]

Please check if your output cycle time parameter t is set to 2s by default. Also please check if your parameter OUTL is set to 0. If you issue remains, you may need to give a call to Auber support and verify all the settings there.

Here is an example to ramp up from ambient to 400 in one hour

C01 = 80, T01 = 60 //ramp up from 80 to 400 in one hour
C02 = 400, T02 = 15 //hold at 400 for 15mins
C03 = 400, T03 = -121 //stop

To heat up from 80 to 400 in 60 mins, the ramp rate is 5.33 degrees per minute, or 0.089 degrees per second, which is a very slow ramp rate. Assuming your heater's max rate is 80 to 400 in 4 mins, which is 80 degrees per minute or 1.33 degrees per second. I don't think you can really reduce the rate from 1.33 degrees per second to 0.089 degrees per second, which is 93% reduce. Yes, you can try to reduce OUTH value down and see how it works. 
If still no help, you may need to consider using a smaller heating element, or maybe you can consider using a PID with SSVR approach, to reduce the voltage output, instead of the time proportional ON/OFF solution provided by SYL-2352P. 

[LaneLearning]

I've tried the cycle time at 1 as well as 2seconds with the same result.  Regardless, during ramping, the SYL-2352P provides full 240 volts to the coil.  The only way I can achieve getting the controller to activate the SCR (the SSR) in a time domain limited fashion is to set the OUTH to something less than 100.  For instance, when I set the OUTH to 50, during ramp up, the coil is powered with a 50% off time as designed.  In all of these instances, the OUTL is set at 0.  I've got an o-scope monitoring the delivered voltage to the heating coil to verify this as well as a current sensing coil and volt meter. 

Here is a list of typical settings that I've used:
ALM1: 600
ALM2: 30
Hy-1: 9999
HY-2: 9999
Hy:  0.3
At: 3
I: 750
P: 48
d: 21
t: 1
Sn: 0
dP: 0
P-SL: 30
P-SH: 600
Pb: 0
OP-A: 0
OUTL: 0
OUTH: 50 or 100
AL-P: 0
COOL: 10
Addr: 1
bAud: 4800 (It came with the 4800 setting and I can't get it to take 9600)
FILt: 0
A-M:  2
LocK: 808

I hope you see something wrong in my settings that I can alter to get this thing to ramp up using time domain drive.  I'm pretty sure it should drive the ramp function by altering the Von time to deliver the appropriate on time to ramp at whatever the ramp speed demands.  I sure hope to be able to use it that way. 

My Oscope verifies that when in the PID mode near my target voltage, the controller is able to deliver tiny fractions of "on time".  Clearly, the controller and deliver in that mode...  I can't figure out why it can't do the same during ramp up (like I assume it is supposed to be able to). 

I really appreciate your help KKane!  Fingers crossed

[Kkane]

Other than T and AL-P, your parameter looks good.

For SSR PID system, t=1 doesn't really help since the AC frequency in US is 60Hz, which will reduce your control resolution. One complete 60Hz sineware period is 16.67ms, which is larger than 10ms (1% of 1000ms).You can set it back to 2s.

AL-P default is 17. If you set it to 0, it means all alarms functions are assigned to AL2 relay, and the display will flash alarm when it is triggered.

Your P,I and D values are different than the default values, which is normal if you ran auto-tune before.

The bottom line is, if reducing OUTH helps your control, you can keep it.

Again, if I'm right, your issue is because that your heater is too powerful to achieve your required slow ramp rate.

[LaneLearning]

I'm a bit confused regarding how this SLY-2352P controller works.  I assumed it used basic AC phase control to titrate the amount of "on" time out of a cycle delivered to the load. I figured this was how it allowed the ramp temperature control.  A slow ramping speed would deliver a very small fraction of a total cycle to the load.  A faster ramping speed would deliver a higher fraction of a total cycle to the load.  But i'm gathering this controller does not allow setting a variable ramping speed.  Is that true? 

I can tell with my oscope that the PID function indeed uses a form of AC phase control to control the phase on percentage to very tiny, sensitive levels.  And i can see that if i set the OUTH level to 50, the controller uses AC phase control to control the phase on to exactly 50% and therefore decrease the speed of heating during ramping. 

I'm hoping i'm wrong and the controller can actually be used to set a slow ramp time that does use AC phase control. 

[LaneLearning]

KKane,

thank you for your help.  And i owe you an apology.  indeed i was wrong in the way i was setting the time value.  When i used the correct method, i was able to alter the ramp rate.  And it indeed uses a time on time off methodology.  This what i was referring to as AC phase control.  perhaps my vernacular is incorrect, but i'm an old engineer and make plenty of mistakes - haha. 

I'm pleased with this controller and am really glad i don't have to use the OUTH function to control the ramp.  thanks for your patience. 

[Kkane]

I'm glad to hear that you fixed your issue. The ramp soak programming in this controller is a little bit tricky and you need some times to learn it. If the program is incorrect, most likely it will not function as designed.

If you are interested, you can check the programming examples in its manual on the last several pages, which will be easier to read and understand.