User manual

PoStep60 user manual
29
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8.3.15 0x24 – Read temperature limit
To read temperature limit first Master writes 0x24 command (no data bytes are needed). In a next
step Master reads one byte of data. Calculated temperature is:
Temperature/ºC = BYTE0
8.3.16 0x25 – Read faults
First Master writes 0x25 command (no data bytes are needed). In a next step Master reads one byte
of data. Each bit in the read byte represents one fault. 0 represents no faults and 1 represents fault
occurred.
Bit
Error
Description
0 (LSB)
OTS
Device has entered over temperature shutdown. OTS bit will clear once
temperature has fallen to safe levels
1
AOCP
Channel A overcurrent shutdown. Please check wiring or possible short circuit.
2
BOCP
Channel B overcurrent shutdown. Please check wiring or possible short circuit.
3
APDF
Channel A predriver fault. Please check driver settings.
4
BPDF
Channel B predriver fault. Please check driver settings."
5
UVLO
Power supply voltage too low Bit clears after voltage rises above lower limit.
6
STD
Stall detected.
7 (MSB)
STDLAT
Latched stall detect.
Fault 0 (OTS) cannot be cleared due to the nature of the fault. Faults 1 – 5 can be cleared and
operation resumed by writing 0 to the bit location. Please see subsection 8.3.22 0x35 – Reset faults.
Faults 6 and 7 are faults related to stall detection and are not real faults – they are not stopping
operation of the PoStep60 driver. The faults 6 and 7 can be ignored.
8.3.17 0x30 – Set full scale current
Master writes 0x30 command followed by two bytes of data. BYTE0 and BYTE1 are calculated as
follows:
int Tq = 123 * xxCurrent; //xxCurrent: current value in A
int Ai = 3;
while(Tq > 255){
Ai--;
Tq = Tq >> 1;
}
(uchar)BYTE0 = Tq;
(uchar)BYTE1 = Ai;
8.3.18 0x31 – Set idle current
Master writes 0x31 command followed by two bytes of data. BYTE0 and BYTE1 are calculated using
same algorithm as in subsection 8.3.17 0x30 – Set full scale current.
NOTE!
When there is no external power supply available the fault data shows 0xFF – all
errors active! Please ignore the value while the power supply is not available.
NOTE!
Limiting values from subsection 6.1 - Electrical specification – limiting values applies.