GE Mark VIe System Manual page 17

1.4.1 I/O Packs
1.4.2 Terminal Boards
Signal flow begins with a sensor connected to a terminal block on a board. Wide and narrow terminal boards are arranged in
vertical columns of high and low-level wiring. An example of a wide board is a board that contains magnetic relays with
fused circuits for solenoid drivers. A shield strip is provided to the left of each terminal block. It can be connected to a metal
base for immediate grounding or floated to allow individual ground wires from each board to be wired to a centralized,
cabinet ground strip.
Simplex Terminal Board
Input
Screws
I/O Pack
Connector
Control System Overview
I/O packs have a common processor board and a data acquisition board that is unique
to the type of connected device. I/O packs on each terminal board digitize the I/O
variables, perform algorithms, and communicate with the controller.
The I/O pack provides fault detection through a combination of special circuitry in the
data acquisition board and software running in the Central Processing Unit (CPU)
board. The fault status is transmitted to and used by the controllers. The I/O pack
transmits inputs and receives outputs on both network interfaces if connected.
Each I/O pack also sends an identification message (ID packet) to the main controller
when requested. The packet contains, the hardware catalog number of the I/O board,
the hardware revision, the board barcode serial number, the firmware catalog number,
and the firmware version. The I/O packs have a temperature sensor that is accurate to
within ±2°C (±3.6 °F). Every I/O pack temperature is available in the database and can
be used to generate an alarm.
Output
Input
Screws
Screws
Public Information
TMR Terminal Board
I/O Pack
Connector
Vote /
Select
I/O Pack
Connector
I/O Pack
Connector
GEH-6721_Vol_I_BP System Guide 17
Output
Screws