Anyone out there using a Hamilton MPE2? I have one integrated onto my STAR systems, it works about half the time… the issue is always “PID control of the valve was lost due to too large of an error between the desired and actual output pressures.”
I am running a filtration step process that takes nearly 2 hours to complete.
ControlPoint = pressure,15,300" looped 3 times ---- top wells off ---- loop x times.
I clean my system daily with EtOH and DI water after.
I’ve used one in the past, but don’t have access to one at the moment to test. I remember it being a bit finnicky to initialize correctly at the start of a method, but didn’t have issues once it got going. Our filtration steps were more like 3 minutes, so a far cry from 2 hours.
It sounds to me like the PID controller output is maxing out (aka the valve is fully open) and the pressure feedback is still too far from the setpoint. What is your air source? There’s a chance that the MPE2 is using more air than the source can generate, and therefore the pressure is slowing dropping out of range over the 2 hours.
Could also be more of a software issue, something like integral windup in the PID controller. Have you tried, say, two 1 hour filtration steps instead of one 2 hour step?
Thank you for this post! We have air line from the wall into regulator (100psi) then to MPE2 control box which connects to the MPE. I have broken my cycles in 5 min intervals in hope to not reduce work load on the device. Still getting back the PID issue, after 20 - 120 seconds into the cycle.
I have sent it in to Hamiltons MPE2 team, so if I have any further development I will be sure to enlighten all using this product.
Can you share the full text of the error? It should say whether it’s associated with the high pressure valve, low pressure valve or manifold. A valve error can be a sign of a leak. One thing to test would be holding at 10 psi which goes through the low pressure circuit and holding at 20 psi and seeing if either of those error.
Reviving an old topic, but I ran across this issue. My fix was to ramp up/down the pressure slowly. I ramped 1psi/second and that cleared up the error message. I’m sure you could use a faster ramp speed, but this was the first rate that was error free for me and the time savings would be minimal for my application.
I worked with it a few years ago. One of the issues I found was the input pressure being to close to the minimum required. Then when the cycle started there was always momentary small drop in pressure that would cause issues if it went down lower than the min pressure required by the MPE2.
Increasing the input by ~20psi did the trick. I think input ended up being around 100psi to get it to work in a stable way.
Also, as others mention, ramping up the pressure in small stretches helps preventing this error.