POST Static and Dynamic Thresholds
The POST (Power-On Self-Test of the bridge) performs two tests. The limits are not configurable.
1) The POST static gating test measures the voltage on each of the three phases before the bridge is enabled. The three voltages must measure 50% (+/- 25%) of battery voltage to pass.
2) If the static test passes the POST dynamic gating test enables and PWMs only one of the 6 FETS at a time. The 3 low side voltages must measure 15% (+/- 10%) of battery voltage. The three high side FETS must measure 85% (+/- 10%) of battery voltage.
The tests happen each time you enable a motor (if the motor is not already turning).
When you get static errors you can actually just read the live phase A voltage (B and C as well) and test results.
POST Static Gating Test Registers:
| Name | Description | Units | Address |
|---|---|---|---|
Phase A Voltage |
Measured Instantaneous motor phase A voltage | V | 285 |
Phase B voltage |
Measured instantaneous motor phase B voltage | V | 286 |
Phase C voltage |
Measured instantaneous motor phase C voltage | V | 287 |
Open circuit voltage test window |
Open circuit test voltage bounds, range 0 to 0.45 | V (norm) | 47 |
motor phase U open circuit voltage POST |
Measured phase U open circuit voltage normalized to the battery voltage | V (norm) | 306 |
motor phase V open circuit voltage POST |
Measured phase V open circuit voltage normalized to the battery voltage | V (norm) | 307 |
motor phase W open circuit voltage POST |
Measured phase W open circuit voltage normalized to the battery voltage | V (norm) | 308 |
POST Dynamic Gating Test Registers:
| Name | Description | Units | Address |
|---|---|---|---|
High/Lowside turn on voltage test window |
High/Low-side turn on test voltage bounds | V (norm) | 48 |
motor phase U high voltage POST |
Measured phase U voltage at 85% duty cycle normalized to the battery voltage | V (norm) | 300 |
motor phase U low voltage POST |
Measured phase U voltage at 15% duty cycle normalized to the battery voltage | V (norm) | 301 |
motor phase V high voltage POST |
Measured phase V voltage at 85% duty cycle normalized to the battery voltage | V (norm) | 302 |
motor phase V low voltage POST |
Measured phase V voltage at 15% duty cycle normalized to the battery voltage | V (norm) | 303 |
motor phase W high voltage POST |
Measured phase W voltage at 85% duty cycle normalized to the battery voltage | V (norm) | 304 |
motor phase W low voltage POST |
Measured phase W voltage at 15% duty cycle normalized to the battery voltage | V (norm) | 305 |