abaco systems CEI-520 - CEI-420;420 A;520;520 A;620;820 Discrete Inputs; Figure 20. CEI-420;420 A;520;520 A;620;820 Discrete Input Circuit; Table 34. Programming Examples; Table 35. Read Discrete Input (AR_GET_CONFIG) Format

Installation CEI-420/420A/520/520A/620/820 Discrete Inputs
CEI-100/CEI-200/CEI-x20 User’s Manual 39
3. All Four Inputs Discretes use the same threshold set by the
AR_SET_CONFIG API routine.
4. Minimum Threshold value is 0 Volts with a code of 00h.
Table 34. Programming Examples
Signal Type
General
28V Avionics
2
TTL/CMOS
Threshold (Volts)
V
TH
18
1.5
Programmed Value (Hex)
V
TH
/LSB
1
4D
4D
Jumper Setting
Installed
Open
1. LSB value from Operating Modes Specification table.
2. Default Configuration from the factory.
Table 35. Read Discrete Input (AR_GET_CONFIG) Format
Discrete #
3
2
1
0
Value - condition
0 : V
IN
(3) < V
TH
1 : V
IN
(3) > V
TH
0 : V
IN
(2) < V
TH
1 : V
IN
(2) > V
TH
0 : V
IN
(1) < V
TH
1 : V
IN
(1) > V
TH
0 : V
IN
(0) < V
TH
1 : V
IN
(0) > V
TH
1. There is ~4mV (jumper not installed) of internal hysteresis for
clean switching.
2. V
TH
Threshold Voltage.
3. V
IN
(0) Discrete # 0 Input Voltage.
CEI-420/420A/520/520A/620/820 Discrete Inputs
Each of the CEI-420/420A/520/520A/620/820 discrete inputs has a circuit
as shown in Figure 20.
22K
4.7K
+5V
DISCRETE
Logic-level
Output
Fixed
Comparator
Threshold
(+4.0V)
Comparator
Figure 20. CEI-420/420A/520/520A/620/820 Discrete Input Circuit
Notes:
Notes:
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com