- Emerson Remote Terminal Unit Instruction Manual

2-20 / Installation & Operation CI-ControlWave Express
2.3.4.8 Non-isolated High Speed Counter/Digital Inputs
Process I/O Board Terminal Block connector TB4 provides the interface to two internally-
sourced single-ended High Speed Counter/Digital Inputs (HSC/DIs). All Input circuits have
surge suppression and signal conditioning. HSC inputs are switch-selectable (SW1-1 for
HSC1 & SW1-2 for HSC2) for high frequency (10 kHz) or low frequency (300 Hz).
High Speed Counter/Digital inputs are sourced from 3.3Vdc and are switch selectable for a
source current of 200uA or 2.2mA (SW1-3 ON = 2.2mA, OFF = 200uA). Note: SW1-3 sets all
DIs and all HSCs.
2.3.4.8.1 High Speed Counter Configurations
A total of 2 HSC inputs with surge protection are provided. HSC Configuration Switches
must be set per Table 2-9.
Table 2-9 - Non Isolated HSC/DI Switch Assignments
Switches Purpose Notes
SW1-1
SW1-2
Configures HSC1
Configures HSC2
OFF = High Frequency (10 kHz)
ON = Low Frequency (300 Hz)
SW1-3 HSC Source Current
OFF = 200uA Source Current
ON = 2.2mA Source Current
2.3.4.9 Non-isolated Pulse Counter/Digital Inputs
CPU/System Controller Edge connector TB5 provides the interface to two non-configurable
Open Collector Pulse Counter/Digital Inputs (Pulse 1 and Pulse 2). Pulse Counters act like
high speed counters but cannot be used with contact relays because they lack contact
debounce circuitry. Signal conditioning circuitry provides 20 microsecond filtering. Each
Pulse Counter/Digital input circuit has surge suppression which consists of a 16V transorb
between signal and ground. Pulse Counter/Digital Inputs are field driven by open collector
circuits and are sourced for 3.3V (internally) with a 200uA source current. Maximum input
frequency for each Pulse Counter/Digital Input circuit is 10 kHz. Figure 2-10 shows the
Open Collector Wiring arrangement.
Figure 2-10 - Pulse Input Wiring Diagram
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