Installation
CEI-220 Discrete Inputs
CEI-100/CEI-200/CEI-
x20 User’s Manual
38
threshold and dividing by the LSB value from the Table 33, for your
chosen mode.
As you can see in Table 34, one value may be appropriate for various
modes. The logical value of the discrete inputs is returned from the
AR_GET_CONFIG API routine. The format is shown in Table 35.
Table 32. Typical Discrete Input Application
Mode
Typical Application
Avionics
Open/Low
Input is driven to 0 Volts (Ground). Floats when not driven
such as a switch, relay closures with a pole tied to ground, or
an open collector driver. This mode handles wider voltage
ranges than CMOS/TTL Open Collector Mode. This
accommodates for large ground potential differences. The
CEI-220 provides a 47K
pull-up resistor to the voltage
applied to the DISINHIn input.
Avionics
Open/High
Input is driven to a supply voltage. Floats when not driven.
This includes switches or relays with a pole tied to a supply
voltage.
Avionics
High/Low
Input is driven between a supply voltage and 0 Volts.
CMOS/TTL
Input is driven by either a TTL or CMOS (5V or 3.3V) driver
CMOS/TTL Open
Collector
Either an open collector or open drain logic device drives
input. The CEI-220 provides a 47K
pull-up resistor to the
voltage applied to the DISINHIn input. The maximum
threshold is 4.98 Volts.
Table 33. CEI-220 Discrete Input Operating Modes Specification
Discrete
Input Mode
Jumper
1
(J2-J5)
DISINHIn
Connection
DISINLOn
Connection
Typical
Accuracy
(Percent
Full Scale)
Full Scale
Threshold
(Volts)
2,3,4
Typical
LSB
Value
(Volts)
Low
Pass
Filter
(Hz)
Avionics
Open/Low
Installed
Supply Voltage Discrete Input
6%
59.766
60/256
340
Avionics
Open/High
Installed
Discrete Input Open
6%
59.766
60/256
340
Avionics
High/Low
Installed
Discrete Input Open
6%
59.766
60/256
340
CMOS/TTL
Not
Installed
Discrete Input Open
4%
4.980
5/256
None
CMOS/TTL
Open Collector
Not
Installed
Supply Voltage Discrete Input
4%
4.980
5/256
None
1. Jumper installed by default.
2. Inputs protected to
100 Vdc.
Notes:
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