RIMS - DYI

[sbaldus8539]

I’m making a RIMS tube using Inkbird 106VH. The documentation that came with it is poor. So far I’d say Inkbird customer service isn’t any better. I’ve got it going, but the output cycles ON / OFF when it should be off. Also, what parameter controls the window or +/- from the set temperature? Thanks in advance.

 

[doug293cz]

I’m making a RIMS tube using Inkbird 106VH. The documentation that came with it is poor. So far I’d say Inkbird customer service isn’t any better. I’ve got it going, but the output cycles ON / OFF when it should be off. Also, what parameter controls the window or +/- from the set temperature? Thanks in advance.

The 106VH is a PID which adjusts the amount of power output to keep a constant set temperature, so even when you are at your target temp, the power will still be turning off and on. Also, a PID does not have a hysteresis band (+/- window) like typical fermentation chamber, or keggerator/keezer controllers.

Brew on

 

[sbaldus8539]

Doug,
Thanks for your reply. I’ve seen PIDs used for RIMS, but question if this is the correct application? It just seems strange to have it pulse on and off. Not being able to control the “hysteresis band” or ON / OFF temperature is also unusual to me. So, a PID will pulse on / off; will it pulse less the closer it is to the target?

Thanks!

 

[doug293cz]

Most PID's control power output by using Pulse Width Modulation (PWM.) For example, if the cycle time is 2 sec, then

@100% power the output is on full time​

@75% power the output is on for 1.5 sec and off for 0.5 sec​

@50% power the output is on for 1.0 sec and off for 1.0 sec​

@25% power the output is on for 0.5 sec and off for 1.5 sec​

@10% power the output is on for 0.2 sec and off for 1.8 sec​

When the system is heating up, the power will typically be at 100%. As the temp gets closer to the setpoint, the power is reduced to prevent overshooting. When you reach the setpoint the power is set at a level just high enough to keep the temperature constant, but will still be pulsing on and off.

The PWM cycle time is a settable parameter in the PID. For brewing use, especially RIMS, the cycle time should be set to the minimum allowed by the PID, usually 1 or 2 seconds.

PID stands for Proportional, Integral, and Differential. The PID algorithm is a mathematical formula that determines what level to set the power output. The proportional component sets the power output based on the difference between the current temperature and the setpoint. The further below the setpoint, the higher the output. The Integral component compensates for an offset between the steady state temp and setpoint. The differential component causes the output to be higher the slower you are approaching the setpoint, and lower the faster you are approaching the setpoint. This helps prevent overshooting the setpoint.

Brew on

 

[sbaldus8539]

Most PID's control power output by using Pulse Width Modulation (PWM.) For example, if the cycle time is 2 sec, then

@100% power the output is on full time​

@75% power the output is on for 1.5 sec and off for 0.5 sec​

@50% power the output is on for 1.0 sec and off for 1.0 sec​

@25% power the output is on for 0.5 sec and off for 1.5 sec​

@10% power the output is on for 0.2 sec and off for 1.8 sec​

When the system is heating up, the power will typically be at 100%. As the temp gets closer to the setpoint, the power is reduced to prevent overshooting. When you reach the setpoint the power is set at a level just high enough to keep the temperature constant, but will still be pulsing on and off.

The PWM cycle time is a settable parameter in the PID. For brewing use, especially RIMS, the cycle time should be set to the minimum allowed by the PID, usually 1 or 2 seconds.

PID stands for Proportional, Integral, and Differential. The PID algorithm is a mathematical formula that determines what level to set the power output. The proportional component sets the power output based on the difference between the current temperature and the setpoint. The further below the setpoint, the higher the output. The Integral component compensates for an offset between the steady state temp and setpoint. The differential component causes the output to be higher the slower you are approaching the setpoint, and lower the faster you are approaching the setpoint. This helps prevent overshooting the setpoint.

Brew on

Thanks for the detailed response. This helps a lot!!

 

[Bobby_M]

Doug,
Thanks for your reply. I’ve seen PIDs used for RIMS, but question if this is the correct application? It just seems strange to have it pulse on and off. Not being able to control the “hysteresis band” or ON / OFF temperature is also unusual to me. So, a PID will pulse on / off; will it pulse less the closer it is to the target?

Thanks!

Actually it's the other way around. It would be impossible to run a RIMS without PID (unless the element's native wattage just happened to be in the right zone for the output temp you wanted to maintain.