- Emerson Remote Terminal Unit Instruction Manual

1-12 / Introduction CI-ControlWave Express
Table 1-4 - CPU/System Controller Bd. Switch SW3 Assignments
RS-485 Loopback & Termination Control (COM3)
Switch
RS-485 Function
Switch ON
Setting
SW3-1 TX+ to RX+ Loopback/2-Wire
ON – 2-Wire Operation or Loopback Enabled
OFF – 4-Wire Operation & Loopback Disabled
SW3-2
TX− to RX− Loopback/2-Wire
ON – 2-Wire Operation or Loopback Enabled
OFF – 4-Wire Operation & Loopback Disabled
SW3-3 100 Ohm RX+ Termination ON – End Nodes Only
SW3-4
100 Ohm RX− Termination
ON – End Nodes Only
SW3-7 RX+ Bias (End Nodes/Node)
ON – 4-Wire = Both End Nodes
2-Wire = One End Node Only
OFF – No Bias
SW3-8
RX− Bias (End Nodes/Node)
ON – 4-Wire = Both End Nodes
2-Wire = One End Node Only
OFF – No Bias
1.3.2.5 CPU/System Controller Board LEDs – LED Board
CPU/System Controller Boards are equipped with a piggyback mounted LED Board. These
LEDs provide the following status conditions when lit:
PG (Red) - Power Good
WD (Red) - a Watchdog condition has been detected
IDLE (Red) - the CPU has free time at the end of its execution cycle
TX1, TX2, TX3 (Red) - transmit activity on COM1, COM2 & COM3 (respectively)
RX1, RX2, RX3 (Red) - receive activity on COM1, COM2 & COM3 (respectively)
Six Status LEDs (Red) - provide run time status codes.
Normally, the Idle LED should be ON most of the time (unless disabled). When the Idle
LED is OFF, it indicates that the CPU has no free time, and may be overloaded.
1.3.2.6 CPU/System Controller Board LEDs
CPU/System Controller Boards are equipped with two red LEDs that provide the following
status conditions when lit: WD (CR1 - Right) – Indicates Watchdog condition has been
detected & IDLE (CR1 - Left) - Indicates the CPU has free time at the end of its execution
cycle. Normally, the Idle LED should be ON most of the time (unless disabled). When the
Idle LED is OFF, it indicates that the CPU has no free time, and may be overloaded.
1.3.3 Process I/O Board
The Process I/O Board is mounted to the CPU/System Controller Board via six nylon
mounting posts.
Interface to the CPU/System Controller Board is provided via a 20-pin connector (P1).
Process I/O Boards contain I/O circuitry that supports the following I/O:
• Four Dedicated Non-Isolated Internally Sourced Digital Inputs
• Two Dedicated Non-Isolated Digital Outputs
• Two Selectable Non-Isolated Digital I/Os which can be individually wired for
Internally-Sourced DI operation or DO operation
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