@dc42 @alankilian @Phaedrux
Thanks for all the help. it is working now.
What I discovered:
The reason my AGC was so good was that the magnet was almost touching the hall-effect sensor. In fact, when I disassembled the MFM I found that the shaft from the hob gear was scratching a nice circle on the top of the hall-effect sensor. I believe this was causing the magnet to turn intermittently.

What I did:
I reprinted the housing using .06mm layers and gradually sanded it down until I got 90 agc. I then moved my MFM mount down about 50mm and added PTFE tubes on the enter and exit. I'm printing a XYZ calibration cube at the moment and here is my M591 D0:

Duet3D rotating magnet filament monitor v3 on pin e0stop, enabled, sensitivity 24.80mm/rev, allow 10% to 190%, check every 10.0mm, version 3, mag 131 agc 91, measured sensitivity 27.16mm/rev, min 89% max 103% over 1234.5mm

Again thanks for all the help.

By the way, that worked. Thanks

@OwenD Ah, that makes sense. As I only have 1 Z probe, the first element in the array would be 0, correct?

I am running a macro that is using the object "sensors.probes[].diveHeight" I know that it has been replaced by sensors.probes[].diveHeights. I ried updating the macro, however, when I replace diveHeight with diveHeights, I get the error:

M98 P"0:/macros/Maintenance/Calibrate Z Offset"
Error: in file macro line 26 column 41: G1: expected numeric operand

Line 26: G1 Z{sensors.probes[0].diveHeights} F360 ; if axes homed move to dive height

If I change it back to diveHeight, I get the warning that the object is obsolete, but the macro works.

@dc42 @alankilian @Phaedrux
Thanks for all the help. it is working now.
What I discovered:
The reason my AGC was so good was that the magnet was almost touching the hall-effect sensor. In fact, when I disassembled the MFM I found that the shaft from the hob gear was scratching a nice circle on the top of the hall-effect sensor. I believe this was causing the magnet to turn intermittently.

What I did:
I reprinted the housing using .06mm layers and gradually sanded it down until I got 90 agc. I then moved my MFM mount down about 50mm and added PTFE tubes on the enter and exit. I'm printing a XYZ calibration cube at the moment and here is my M591 D0:

Duet3D rotating magnet filament monitor v3 on pin e0stop, enabled, sensitivity 24.80mm/rev, allow 10% to 190%, check every 10.0mm, version 3, mag 131 agc 91, measured sensitivity 27.16mm/rev, min 89% max 103% over 1234.5mm

Again thanks for all the help.

@dc42 I reprinted the housing and reassembled but now I'm getting seven red flashes on boot up. If I'm reading the firmware correctly it means that the magnet is too far away (FLASHES_ERR_TOO_WEAK = 7)? Running the M591 D0 results in:

M591 D0
Duet3D rotating magnet filament monitor v1 on pin e0stop, enabled, sensitivity 24.80mm/rev, allow 10% to 190%, check every 10.0mm, no data received

@alankilian I took the housing apart and sanded the inside of the idler to allow the bearing to get closer to the hobbed gear. Put it all back together and still have the same problem. I'm going to try reprinting the housing. If that doesn't work I'll see if I can get the housing SLA printed.

Thanks for now.

@phaedrux The printer is a D-bot using the bowden-type extruder. Below is a picture of it. The bracket below the extruder holders the filament sensor.

Upon power up I get three green flashes. When the printer is extruding I am seeing green and red flashes on the led.

I modified the M591 parameters to give a wider tolerance range and increased the distance between comparisons but I still get the same error.

M591 D0
Duet3D rotating magnet filament monitor v3 on pin e0stop, enabled, sensitivity 24.80mm/rev, allow 10% to 190%, check every 20.0mm, version 3, mag 132 agc 88, measured sensitivity infmm/rev, min 0% max 0% over 42.3mm

M122
M122
=== Diagnostics ===
RepRapFirmware for Duet 2 WiFi/Ethernet version 3.2.2 running on Duet WiFi 1.02 or later
Board ID: 08DJM-9178L-L2MS8-6J9DA-3S86J-K8GAN
Used output buffers: 3 of 24 (22 max)
...
=== Filament sensors ===
Extruder 0: pos 0.00, errs: frame 0 parity 0 ovrun 0 pol 0 ovdue 0

I am trying to perform the calibration but shortly after the print starts the job pauses and the error message "Extruder 0 reported 'tooLittleMovement'" is displayed.

Magnetic Filament Monitor v1.7a connected to Duet Wifi E0 endstop using a crossover cable.

M591 D0
Duet3D rotating magnet filament monitor v3 on pin e0stop, enabled, sensitivity 24.80mm/rev, allow 70% to 130%, check every 3.0mm, version 3, mag 132 agc 88, measured sensitivity infmm/rev, min 0% max 0% over 11.2mm

The sensor is mounted below and against the extruder.

What steps should I take to troubleshoot this error?

Thanks

I was assembling the sensor and dropped the hobbed assembly which broke the magnet in two. Is there a way to replace just the magnet or do I need to replace the whole assembly? Is it possible to just buy the assembly or do I need to replace the whole sensor?

Thanks!

I have a DuetWifi 1.02 running firmware 2.02(RTOS) (2018-12-24b1). I double-checked my configuration and it is actually my E0 end stop that is not functioning. If I disconnect all connectors from the board and power it through the USB port, when I issue a M119 the output is "Endstops - X: not stopped, Y: not stopped, Z: at min stop, Z probe: at min stop". Note that I am using a BLTouch for my Z probe which is connected to the probe port and the Heater 3 for control, hence the Z at min reading. I'm not sure why the E0 & E1 endstops do not report in M119 but on the Machine Properties page it shows for E0 "Endstop hit = Yes".