ESD electronic CAN-CBM-PLC/331-1, Hardware Manual

Page: 120 / 149

Commands and Parameters
esd Protocol for CAN Modules Rev. 3.2 3 - 9
The kind of the parameters interchanged to the module depends on the selected sub
command:
Sub command $00 --
<
store parameter
active
mod. no...
To store all interchanged parameters (also those of other commands) the actual
module no. has to be entered into byte 5 when calling this sub command.
The actual module no. is either the number adjusted by the coding switches (default
parameter active) or the number changed by sub command 'set module no.'.
Sub command $01 --
<
set module no.
new. mod. no.. Here the desired new module no. is entered. The module is addressed immediately
after this command by the new module no. The module no. adjusted by the coding
switches is ignored.
If the new module no. should remain active after a RESET, the parameters have to
be stored by the sub command 'store parameters' before a power down or a RESET.
Sub command $02 --
<
set CAN-status byte
cstat... A 'set' access onto the CAN-status byte sets the bits 2 and 7 of the byte to '0'. All other bits of the
status byte remain unchanged, because they serve as read only information (see also 'requesting the
actual parameters').
Bit 2 shows that a CAN error has been detected by the module. The bit serves the
documentation of errors which do not cause a 'standstill' for the CAN, but remain
only for a short period. Error arising for a short time can easily be overlooked,
because they make themselves visible only by a temporal limited flashing of the
status LED.
The bit is set to '1' when an error has been detected. A 'set' access with any data
(recommended: byte 5 = $00) onto the status byte or each RESET reset the bit back
to '0'.
The CAN-error bit can also be reset by the supervisor command 'reset CAN error'
(sub command $05). The other bits remain unchanged by this command.