| When the Citect CCM driver is establishing
communications with the PLC it sends a request to the Scratchpad,
if the PLC responds then the driver will set the Unit status to
Online. Unfortunately GE seem to have a problem with the new 925
CPU to CCM module communications. In this model, requesting a read
from the CCM Scratchpad causes the CCM processor to hang up. This
has been verified by two other diverse methods as to be the case.
If any other command (such as read a register) is made, the CCM
module responds and operates correctly (provided it has not been
caused to hang up by a previous read Scratchpad command). A hang up
in this case means that the CCM module refuses to respond to
<ENQ> from the other unit |
