Disable feedback current readout on flawed HW Revs #96

atse · 2024-01-31T12:17:48+08:00

atse commented

2024-01-31 12:17:48 +08:00

Thermostats v2.2 and below have a noisy and offset feedback current tec_i caused by missing hardware on 2 MAX1968 TEC driver pins:

A missing RC filter on the ITEC pin that would have isolated CPU
sampling pulses from the signal; and
Some missing buffering on the VREF pin that would have avoided
loading the VREF signal, preventing voltage drops from the nominal 1.5V.

Since the resulting signal tec_i derived from these two signals can have an error of around +/- 100mA, and readback may affect the stability performance of the Thermostat, disable current readback entirely on affected hardware revisions for now.

See https://github.com/sinara-hw/Thermostat/issues/117 and https://github.com/sinara-hw/Thermostat/issues/120.

On hardware revisions v3.x and above, this would be fixed.

Thermostats v2.2 and below have a [noisy and offset feedback current `tec_i`](https://git.m-labs.hk/M-Labs/thermostat/issues/92) caused by missing hardware on 2 MAX1968 TEC driver pins: 1. A missing RC filter on the ITEC pin that would have isolated CPU sampling pulses from the signal; and 2. Some missing buffering on the VREF pin that would have avoided loading the VREF signal, preventing voltage drops from the nominal 1.5V. Since the resulting signal `tec_i` derived from these two signals can have an error of around +/- 100mA, and readback may affect the stability performance of the Thermostat, disable current readback entirely on affected hardware revisions for now. See https://github.com/sinara-hw/Thermostat/issues/117 and https://github.com/sinara-hw/Thermostat/issues/120. On hardware revisions v3.x and above, this would be fixed.

atse added 1 commit 2024-01-31 12:17:48 +08:00

ae3d8b51d4 Disable feedback current readout on flawed HW Revs

Thermostats v2.2 and below have a noisy and offset feedback current
`tec_i` caused by missing hardware on 2 MAX1968 TEC driver pins:

1. A missing RC filter on the ITEC pin that would have isolated CPU
sampling pulses from the signal; and
2. Some missing buffering on the VREF pin that would have avoided
loading the VREF signal, preventing voltage drops from the nominal 1.5V.

Since the resulting signal `tec_i` derived from these two signals can
have an error of around +/- 100mA, and readback may affect the stability
performance of the Thermostat, disable current readback entirely on
affected hardware revisions for now.

See https://github.com/sinara-hw/Thermostat/issues/117 and
https://github.com/sinara-hw/Thermostat/issues/120.

On hardware revisions v3.x and above, this would be fixed.

sb10q merged commit ae3d8b51d4 into master

2024-01-31 12:18:47 +08:00

linuswck referenced this pull request

2024-05-02 17:45:30 +08:00

Improve ADC Readings with Averaging Filter #105

Sign in to join this conversation.

No reviewers

No Label

No Milestone

No Assignees

1 Participants

Notifications

Due Date

The due date is invalid or out of range. Please use the format 'yyyy-mm-dd'.

No due date set.

Dependencies

No dependencies set.

Reference: M-Labs/thermostat#96