Detec­tion of short cir­cuits in the CAN bus – Error pat­terns

The robust­ness of the CAN bus also based on its tole­ran­ce to occur­ring short cir­cuits. In the fol­lowing, we sum­ma­ri­ze the pos­si­bi­li­ties and show how the CAN­touch detects the­se errors.

CaseDescrip­ti­onCom­mu­ni­ca­ti­onCAN­touch

Bus Sta­tus

CAN­touch 

CAN Levels
Abso­lu­te

CAN­touch

Node Mea­su­re­ment

CAN­touch

Bus Wiring

OK

CAN-Bus without errors

yes
Remark I Bus Sta­tus : valid CAN messages avail­ab­le

 
CAN_​H
shor­ted to
CAN_​V+

 
noTest set­up without com­mu­ni­ca­ti­on
Remark Vdepends on the CAN trans­cei­ver type, some types can still com­mu­ni­ca­te with this error

Remark VIdepen­ding on the vol­ta­ge level and the dura­ti­on of the error (over­hea­ting of the CAN trans­cei­ver)

Remark IIBus Sta­tus : sta­ti­cal­ly reces­si­veRemark IVMea­su­re­ment not pos­si­ble without com­mu­ni­ca­ti­onRemark IIIfinds errors when sup­ply vol­ta­ges are mea­su­red too


CAN_​L
shor­ted to
CAN_​V+


noTest set­up without com­mu­ni­ca­ti­on
Remark Vdepends on the CAN trans­cei­ver type, some types can still com­mu­ni­ca­te with this errorRemark IIBus Sta­tus : sta­ti­cal­ly reces­si­veRemark IVMea­su­re­ment not pos­si­ble without com­mu­ni­ca­ti­onRemark IIIfinds errors when sup­ply vol­ta­ges are mea­su­red too


CAN_​H
shor­ted to
Vcc


yes
Remark I Bus Sta­tus : valid CAN messages avail­ab­leRemark VII Error in dif­fe­ren­ti­al signal not detec­ta­bleRemark VIIIA wiring test with con­nec­ted par­ti­ci­pants remains not recom­men­ded. It pro­vi­des unde­fi­ned errors who­se state­ments are dif­fi­cult to judge. The dis­play­ed results depend stron­gly on the inter­nal wiring of the par­ti­ci­pants.


CAN_​L
shor­ted to
Vcc


no
Remark IIBus Sta­tus : sta­ti­cal­ly reces­si­veRemark IVMea­su­re­ment not pos­si­ble without com­mu­ni­ca­ti­onRemark VIIIA wiring test with con­nec­ted par­ti­ci­pants remains not recom­men­ded. It pro­vi­des unde­fi­ned errors who­se state­ments are dif­fi­cult to judge. The dis­play­ed results depend stron­gly on the inter­nal wiring of the par­ti­ci­pants.


CAN_​H
shor­ted to
CAN_V-


no
Remark IIBus Sta­tus : sta­ti­cal­ly reces­si­veRemark IVMea­su­re­ment not pos­si­ble without com­mu­ni­ca­ti­onRemark IIIfinds errors when sup­ply vol­ta­ges are mea­su­red too


CAN_​L
shor­ted to
CAN_V-


yes
Remark VII Error in dif­fe­ren­ti­al signal not detec­ta­bleRemark IIIfinds errors when sup­ply vol­ta­ges are mea­su­red too


CAN_​H
shor­ted to
CAN_​L


no
Remark IIBus Sta­tus : sta­ti­cal­ly reces­si­veRemark IVMea­su­re­ment not pos­si­ble without com­mu­ni­ca­ti­on

Legend :

Vcc : Sup­ply vol­ta­ge of the CAN trans­cei­ver

I) Bus Sta­tus : valid CAN messages avail­ab­le

II) Bus Sta­tus : sta­ti­cal­ly reces­si­ve

III) finds errors when sup­ply vol­ta­ges are mea­su­red too

IV) Mea­su­re­ment not pos­si­ble without com­mu­ni­ca­ti­on

V) depends on the CAN trans­cei­ver type, some types can still com­mu­ni­ca­te with this error

VI) depen­ding on the vol­ta­ge level and the dura­ti­on of the error (over­hea­ting of the CAN trans­cei­ver)

VII) Error in dif­fe­ren­ti­al signal not detec­ta­ble

VIII) A wiring test with con­nec­ted par­ti­ci­pants remains not recom­men­ded. It pro­vi­des unde­fi­ned errors who­se state­ments are dif­fi­cult to judge. The dis­play­ed results depend stron­gly on the inter­nal wiring of the par­ti­ci­pants.

Article last edited onArticle first published on
2020/​01/​082019/​09/​30