Common Module - GasTech GTA-4100R Operator's Manual

There are five types of terminal block connectors on each back plane.
1. SENSOR INPUTS - First at the top right for top channel, or bottom right for bottom channel is the
sensor connector. This is a 2.5mm 3 way removable connector which is fitted to all back planes. The
terminals are clearly marked on the PCB. Some examples for common sensors are shown later in this
manual or you can refer to the sensor manual for the correct connection details.
2. COMMON ALARM RELAYS - The second set of connectors are the individual alarm relay connectors,
this is to the right of the sensor connector a 3 tier non-removable 1.5mm connector. The terminals
are for "N/C" Normally Closed, "C" Common, and N/O Normally open contacts. These are clearly
marked on the PCB. The bottom tier is for Fault, the middle tier is for "AL1" (alarm 1) and the top tier
is for "AL2" (alarm 2).
3. REMOTE 4-20mA OUTPUT - The third connector is a 1.5mm removable connector at the top of the
relay connector. This is the 4-20mA output for each channel. The terminals are clearly marked on the
PCB "+ and –"
4. POWER – The power terminal block is a 2.5mm connector. On the standard 19" rack, the power
connector is a 3-way type at the top of the PCB between channel 17 and 19. There are two 5 Amp
fuses either side of the connector – one for the top channel and one for the bottom channel.
On the Micro Rack
to the 5 Amp fuse. There is a green LED next to the power connector on each PCB which indicates that
the board is receiving power. There is also a red LED next to each fuse. If a fuse is blown this red LED
will illuminate. The polarity for these power terminals are clearly marked on the PCB.
5. COMMON RELAYS – Each back plane contains common relays. These will be discussed in the next
section.
2.2.1

Common Module

The common modules purpose is to synchronize all the 4100R cards flashing LEDS as well as common up all the
alarm relays and runs a local buzzer. It also provides a global Ack/Reset button.
Common module
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TM
the power connector is a 2-way type located on the right side of the board, next
Common module
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