PT100 sensor on Duet2 sporadically hunting for target temp

mitch

After trying numerous times the macro just started running. Part way through I got the heater fault.

Log:

2021-02-28 10:59:51 [info] Event logging started at level debug
2021-02-28 10:59:51 [info] Running: Duet Ethernet 1.02 or later: 3.2 (2021-01-05)
2021-02-28 10:59:51 [info] M291: - WARNING - Grid bed compensation map will be disabled. Ok or Cancel?
2021-02-28 10:59:53 [info] M292: cancelled: false
2021-02-28 10:59:53 [info] M291: - Preheat and Home - Bed and nozzle will preheat and home all axis.
2021-02-28 10:59:54 [info] M292: cancelled: false
2021-02-28 11:00:15 [debug] {"beep_freq":666,"beep_length":500}
2021-02-28 11:00:16 [debug] {"beep_freq":1111,"beep_length":300}
2021-02-28 11:00:16 [info] M291: - [no title] - Preheating the bed to 60 and nozzle to 210 for accurate probing
2021-02-28 11:00:35 [info] M291: - [no title] - Nozzle will now move to center of bed and move close to the bed
2021-02-28 11:00:36 [info] M291: - Setting Z=0 - Carefully Jog the Z Axis until the bed and nozzle are touching and click OK
2021-02-28 11:01:16 [info] M292: cancelled: false
2021-02-28 11:01:16 [info] M291: - [no title] - Nozzle will now move to the 4 leveling points twice.
2021-02-28 11:01:18 [info] M291: - Adjustment Point 1 - Adjust point 1 by using jog to lower nozzle to 0, then use the bed height knobs and a piece of paper to tweak tension.
2021-02-28 11:03:00 [info] M292: cancelled: false
2021-02-28 11:03:03 [info] M291: - Adjustment Point 2 - Adjust point 2 by using jog to lower nozzle to 0, then use the bed height knobs and a piece of paper to tweak tension.
2021-02-28 11:04:05 [info] M292: cancelled: false
2021-02-28 11:04:07 [info] M291: - Adjustment Point 3 - Adjust point 3 by using jog to lower nozzle to 0, then use the bed height knobs and a piece of paper to tweak tension.
2021-02-28 11:04:45 [info] M292: cancelled: false
2021-02-28 11:04:48 [info] M291: - Adjustment Point 4 - Adjust point 4 by using jog to lower nozzle to 0, then use the bed height knobs and a piece of paper to tweak tension.
2021-02-28 11:05:36 [info] M292: cancelled: false
2021-02-28 11:05:36 [info] M291: - [no title] - The adjustment sequence will now repeat for fine adjustment.
2021-02-28 11:05:38 [info] M291: - Adjustment Point 1 - Adjust point 1 by using jog to lower nozzle to 0, then use the bed height knobs and a piece of paper to tweak tension.
2021-02-28 11:06:21 [info] M292: cancelled: false
2021-02-28 11:06:24 [info] M291: - Adjustment Point 2 - Adjust point 2 by using jog to lower nozzle to 0, then use the bed height knobs and a piece of paper to tweak tension.
2021-02-28 11:06:38 [info] M292: cancelled: false
2021-02-28 11:06:40 [info] M291: - Adjustment Point 3 - Adjust point 3 by using jog to lower nozzle to 0, then use the bed height knobs and a piece of paper to tweak tension.
2021-02-28 11:07:13 [info] M292: cancelled: false
2021-02-28 11:07:16 [info] M291: - Adjustment Point 4 - Adjust point 4 by using jog to lower nozzle to 0, then use the bed height knobs and a piece of paper to tweak tension.
2021-02-28 11:07:21 [warn] Error: Heater 1 fault: temperature excursion exceeded 15.0°C (target 210.0°C, actual 225.8°C)
2021-02-28 11:07:23 [info] M292: cancelled: false
2021-02-28 11:07:23 [info] M291: - [no title] - Nozzle will now move to center of bed to reset Z0
2021-02-28 11:07:30 [info] M292: cancelled: false
2021-02-28 11:07:32 [info] M291: - Setting Z=0 - Jog the Z Axis until the bed and nozzle are touching and click OK
2021-02-28 11:10:40 [info] M292: cancelled: false
2021-02-28 11:10:40 [info] M291: - [no title] - The bed has been mechanically leveled and Z0 set.
2021-02-28 11:11:01 [info] M292: cancelled: false
2021-02-28 11:11:01 [debug] {"beep_freq":666,"beep_length":600}
2021-02-28 11:11:02 [debug] {"beep_freq":1511,"beep_length":300}
2021-02-28 11:11:02 [info] M291: - [no title] - Probing complete. Turning off heaters and homing axis.
2021-02-28 11:11:17 [debug] {"beep_freq":666,"beep_length":600}
2021-02-28 11:11:17 [debug] {"beep_freq":1511,"beep_length":300}
2021-02-28 11:11:18 [info] M291: - [no title] - Run Trigger Height Macro to determine trigger height
2021-02-28 11:11:18 [info] Event logging stopped

mitch

@jay_s_uk Thanks,

I updated the file. Seems to still run the same. But I will make sure to find all the macros that have this command and add the quotes.

Just seems like sporadic behavior.

mitch

This may be a combination of some macro issues due to recent firmware updates as well as an intermittent connection near the hotend probe.

Thanks for the help. I am going to try to nail down the probe issue first to start to rule out some variables and make this easier to figure out.

Veti

post a picture of the temperature graph

mitch

I am attempting to run a print right now. The blips in the graph are heater faults I have had to clear. The temp just seems to stay on and then drift, clear it, it works again. Not spikes to 2000 or anything like that.

Veti

those are spikes none the less.

this points to either noise in the pt100 cabling. try to isolate the cables from other cables especially motor cables.

mitch

The PT100 wire is not twisted pair. It is just a straight through cable. However, all of the motor cables are in fact twisted pair.

Is tearing this wire bundle apart and using twisted pair for the PT100 sensor a necessity? If that would eliminate this issue I have not problem doing it. But it is quite the task if it isn't usually necessary.

Veti

for now just run the wire separate and see if the problem persists.

mitch

@Veti Ok, doing that now. I know I read something somewhere about 4wire vs 2wire on the PT100. Right now I am just running a straight 2wire.

Running a separate twisted 2wire now.

mitch

Well, so far so good. I ran a twisted pair and terminated new connectors. One of the two seemed to have fixed this issue for now. Thanks for the help.

Phaedrux

4 wire PT100 is the way to go if you can manage the wiring. I run a 4 wire setup with the two pairs twisted. It runs through a bundle with 2 fans, an extruder stepper, and the heater, for a meter and a half and it's been solid.

dc42

@mitch said in PT100 sensor on Duet2 sporadically hunting for target temp:

I recently changed to the E3D PT100 sensor and Daughterboard. The temps seem to be correct for the hotend but it has a hard time staying on temp. It seems to hunt around the target temp with a variance of about 0.1 - 0.9C even after a PID tune.

Regular oscillations about the target temperature when the print head is stationary suggest that the actual dead time of your hot end is higher than the M307 value. So try increasing the D parameter in your M307 command by about 25%.

Random fluctuations when the head is stationary are more likely to be caused by a bad connection, or by interference from stepper motor wires.