Bed Temp Calibration

[Mike K Ender 5 Pro]

Newbie here.
Is there a way to calibrate the bed temperature? Here is the situation:
I have an Ender 5 pro and have printed several items with PLA. The bed eventually warped so I replaced it with 1/4” (6.35mm) cast aluminum precision plate. I also upgraded the bed heater to a 500 watt 120 volt unit. The heater kit came with a new thermistor which I installed. I printed a few more pla items with no problem.
I recently designed a part that will live outdoors in full sun, so I chose asa resin for uv resistance. And I can’t get good bed adhesion. I tried increasing the temp and found that despite the Ender 5 specs stating a max bed temp of 135 degrees, it would only go to 110. Creality tech support claims that this is the limit, not 135. To make things worse the measured temperature is 10 - 15 degrees cooler than the setting. I feel like if I could get an honest 110 I might have a good chance. But as it is it isn’t sticking. Creality support recommends adjusting the PID parameters for better stability, but I think they are missing the point. Stability is not the issue, accuracy is. Is my thinking right?

[LePaul]

Well a few things, Creality is giving you specs for their bed. I suspect that stock bed is a 24v bed?

You said you went with an AC 500W bed. What thermosistor is that using? There are different types out there, so it may be different that what the Ender 5 Pro's FW is set to

You say resin, then ASA, so those are two different things. Resin, like the liquid, is used in resin printers. I am guessing you have ASA filament, yes?

ASA bed temps should be between 90-120C.

You need to use something to see what that bed temp really is when heated. (IR / laser pointer temp measurement? FLIR? Thermocouple off a multimeter?)

Also, here is how to set up the bed PID in this link

https://teachingtechyt.github.io/calibration.html#pid