Danfoss PVED-CLS User Manual

168 | © Danfoss | August 2018 AQ00000211
ENGINEERING TOMORROW
17.5.2 Sector CRC calculation
Upon having verified the correctness of the data in a given sector, the sector CRC shall be calculated and stored at the
CRC address. The CRC shall be calculated in accordance with CRC-CCITT polynomial, x
16
+ x
12
+ x
5
+ 1 (0x1021).
17.5.3 Example
Example for calculating the sector CRC for “Valve calibration data”:
Name
Address
Data type
Description of parameter
Value
Dec
Value
Hex
Max spool position, left
P3162
S16
Spool left most position
-420
FE5Ch
Max spool position, right
P3164
S16
Spool right most position
420
01A4h
Closed loop dead-band edge,
left
P3166
S16
Spool closed loop dead-band edge,
Left
-105
FF97h
Closed loop dead-band edge,
right
P3168
S16
Spool closed loop dead-band edge,
Right
105
0069h
Open loop dead-band edge
offset
P3170
S16
Spool open loop dead-band offset
25
0019h
Sector CRC
P3183
U16
CRC value for the valve calibration
sector
F934h
Table 79
The data that is target for the CRC calculation is given in Table 79. The last byte that shall be included in the CRC
calculation is P3171 which holds the high byte of the Offset Dead-band OL parameter. Unused byte may be set to 0.
To calculate the sector CRC, the data is first rearranged into little endian format as follows:
“5CFEA40197FF69001900”. The CRC-CCITT result for this data is
F934h.
The low byte (34h) shall be stored at P3183 and the high byte (F9h) at P3184.
17.5.4 Signature CRC calculation
Attention
As a step in safe parameterization of the PVED-CLS software, to ensure the correctness of the data in one or more
modified sectors it shall be signed. Signing off correctness is understood as it has been verified that all values in a sector
are correct. This is valid for the entire parameter sector.
The PVED-CLS software checks the sector data integrity (sector CRC) and if the sector data is approved (Signature
CRC) as an instance of the power-up self-test. The PVED-CLS enters the safe state with a specific CAN diagnostic
trouble code if one of the checks fail.
Important
• Two PSAC (Parameter Sector Approval Code) levels exists; OEM and Dealer.
• See Table 78 for which PSACs are valid for the sectors.
• The PSACs are fixed and cannot be changed for a given application software.
• Contact Danfoss Product Application Engineering for the relevant PSACs.
• It is the responsibility of the OEM/system integrator to keep the PSACs secret for unauthorized personnel.
• The PSACs shall be treated as confidential code and thus not displayed directly on a service tool page.
• Disclosing the PSACs may lead to loss of safety integrity of the product.
The data in a particular sector is approved by the following steps:

Danfoss PVED-CLS Specifications

General

Brand	Danfoss
Model	PVED-CLS
Category	Controller
Language	English