GE Security EST3 - Substituting Known Good Signature Series Devices

Service and troubleshooting
EST3 Installation and Service Manual 8.41
The panel performs a ground fault test for 2 seconds at
40-second intervals. If the system is working properly, the
voltage between earth ground and logic negative should be
between 12.3 Vdc and 16.8 Vdc during the 2-second test. The
system reports a ground fault when the voltages are less than
12.3 and more than 16.8. In a non-faulted system, the voltage
outside the 2-second test period may float randomly, but if the
system is faulted the voltage is likely to be a fixed value such as
3 or 19.
Substituting known good Signature series
devices
When substituting a “known good” detector or module in place
of a suspect device, one of two scenarios can take place.
If the substituted device is the same model as the suspect device,
the system accepts it with no further operator action. When the
substituted device is installed, the system goes into trouble.
When the quantity of devices defined on the circuit is reached,
the system automatically remaps the circuit, stores the revised
information, and returns to normal. This process may take a few
minutes.
If the substituted device is a different model than the suspect
device, when the device count is correct, the Signature controller
module automatically remaps the circuit. A trouble occurs at the
address of the suspect device as the result of a map fault, because
the known good device’s parameters differ from those of the
suspect device that was removed from the circuit. You must
accept the parameters of the known good device to remove the
map fault. These can be changed later.
You cannot use device substitution as a troubleshooting
technique for Signature security devices. By design, the
Signature controller does not automatically remap a replaced
security device. This is intended to prevent swapping a security
device with one that has been compromised for criminal
purposes.
Detectors
When one or more devices are removed from a Signature Data
Circuit for servicing, as shown in Figure 8-11, the panel will
display a trouble condition for each device. If the System
Definition Utility program (SDU) were connected to the panel,
the DSDC Status screen would also indicate a trouble condition
and the need to re-map.
If the detector is removed from an isolator base, the isolator will
transfer.