Omron ZEN - Page 73

49
Wiring Section 2-2
less than 0.8 mA. If the leakage current exceeds this value, insert a
bleeder resistor in the circuit to reduce the input impedance, as
shown in the following diagram.
Note The OFF voltage of the analog/digital input terminals on the CPU
Unit is 30 V DC. A 2-wire DC sensor can not be connected.
Refer to page 123 Input Specifications for details on the values L
C
, I
C
, and E
C
.
The input impedance, input current, and OFF voltage may vary depending on
the input being used.
R
ZEN
Input power
supply
Bleeder
resistor
2-wire sensor, etc.
I: Device's leakage current (mA)
R: Bleeder resistance (kΩ)
W: Bleeder resistor's power rating (W)
The equations above were derived from the following equations:
L
C
: ZEN's input impedance (kΩ)
I
C
: ZEN's input current (mA)
E
C
: ZEN's OFF voltage (V) = 5.0 V
R =
L
c
× 5.0
I
×
L
c
− 5.0
kΩ max.
W =
2.3
R
W min.
R ×
Input voltage (24)
Input Current (I
c
)
R +
Input voltage (24)
Input Current (I
c
)
I ×
≤ OFF voltage (E
c
: 5.0)
W ≥
Input voltage (24)
R
× Input voltage (24) × tolerance (4)
Z211-E1-03.book Page 49 Friday, November 21, 2008 10:38 AM