Discrete Inputs (Di) - Emerson FloBoss 107 Instruction Manual

FloBoss 107 Instruction Manual
4.8

Discrete Inputs (DI)

4-12
INTERNALLY
POWERED
Figure 4-8. Analog Output Wiring
The discrete input (DI) monitors the status of relays, open
collector/open drain type solid-state switches, and other two-state
devices. Discrete inputs come from relays, switches, and other devices,
which generate an on/off, open/close, or high/low signal.
The DI provides a source voltage for dry relay contacts or for an open-
collector solid-state switch.
Each DI channel can be software-configured to function as:
Standard discrete inputs.
Latched discrete inputs.
A latched DI remains in the active state until reset. Other parameters can
invert the field signal and gather statistical information on the number of
transitions and the time accumulated in the on- or off-state.
The DI senses the low voltage, which signals the FB107 electronics that
the relay contacts have closed. The opening of the contacts allows the
voltage to rise and the DI signals the FB107 electronics that the relay
contacts have opened. An FB107 can read a DI a maximum of 20 times
per second (50 millisecond scan).
When a field device (such as a relay contact or open collector) is
connected across + and GND, the closing of the contacts completes the
circuit This activates current flow that the DI circuitry senses and, in
turn, signals the FB107 electronics indicating that the relay contacts
have closed.
Inputs/Outputs and RTD Input Issued Feb-07