Module withdrawal and insertion may only be performed when control power has been removed from the
unit. Inserting an incorrect module type into a slot may result in personal injury, damage to the unit or con-
nected equipment, or undesired operation!
Proper electrostatic discharge protection (i.e. a static strap) must be used when coming in contact with
modules while the relay is energized!
The relay, being modular in design, allows for the withdrawal and insertion of modules. Modules must only be replaced with
like modules in their original factory configured slots. The faceplate can be opened to the left, once the sliding latch on the
right side has been pushed up, as shown below. This allows for easy accessibility of the modules for withdrawal.
MODULE WITHDRAWAL: The ejector/inserter clips, located at the top and bottom of each module, must be pulled
simultaneously to release the module for removal. Before performing this action, control power must be removed
from the relay. Record the original location of the module to ensure that the same or replacement module is inserted
into the correct slot. Modules with current input provide automatic shorting of external CT circuits.
MODULE INSERTION: Ensure that the correct module type is inserted into the correct slot position. The ejector/
inserter clips located at the top and at the bottom of each module must be in the disengaged position as the module is
smoothly inserted into the slot. Once the clips have cleared the raised edge of the chassis, engage the clips simulta-
neously. When the clips have locked into position, the module will be fully inserted.
Type 9G and 9H CPU modules are equipped with 10Base-T and 10Base-F Ethernet connectors. These connectors
must be individually disconnected from the module before the it can be removed from the chassis.
The version 4.0 release of the L90 relay includes new hardware (CPU and CT/VT modules). The new CPU mod-
ules are specified with the following order codes: 9E, 9G, and 9H. The new CT/VT modules are specified with the
following order codes: 8F, 8H.
The new CT/VT modules (8F, 8H) can only be used with the new CPUs (9E, 9G, 9H); similarly, the old CT/VT mod-
ules (8A, 8C) can only be used with the old CPUs (9A, 9C, 9D). To prevent hardware mismatches, the new CPU
and CT/VT modules have blue labels and a warning sticker stating "Attn.: Ensure CPU and DSP module label
colors are the same!". In the event that there is a mismatch between the CPU and CT/VT module, the relay will
not function and a
All other input/output modules are compatible with the new hardware. Firmware versions 4.0x and higher are only
compatible with the new CPU and CT/VT modules. Previous versions of the firmware (3.4x and earlier) are only
compatible with the older CPU and CT/VT modules.
Figure 3–5: UR MODULE WITHDRAWAL/INSERTION
L90 Line Differential Relay
3.1.2 MODULE WITHDRAWAL AND INSERTION
error will be displayed.