User`s manual

XP8000 Series (PLCBus
TM
) Z-World 530-757-3737 7
EEPROM Coefficients
Compensation coefficients, determined by precise measure-
ment, are stored in the on-board EEPROM for each of the 18
software A/D modes.
Measurement of Ambient Temperature
The TEMP pin on U1 (LT10 19 ) puts out a voltage that is directly
proportional to absolute temperature, with a slope of 2.1 mV
per degree. Room temperature (295°K) generates ~620 mV.
Excitation Voltage at Each Input
To provide an excitation voltage at each input channel on head-
ers H1 and H2, install RN2 and RN3 on the board and connect
EX1 (on H1) and EX4 (on H2) to V+ on header H5.
The ADC4
Z-World’s ADC4 expansion board adds eleven 12-bit ADC chan-
nels to your system. Four channels have signal conditioning
that can match your input voltage range. The ADC4 board nor-
mally operates at 24V, but will operate at 12V.
P1
P2
H1
U1
J1, J2
H2
Regulator
U8
PAL
U9
C11
J3
U5
U2
U7
U3
U6
J4, J5
RP4 RP3
Gain and
Bias
The four channels (CH0–CH3) that have signal-conditioning
circuitry, as shown below. You can match the voltage range of
the device you are measuring to the fixed voltage range (2.5V)
of the ADC chip by changing socketed resistors (labelled GAIN
and BIAS here).
–
+
CH0–CH3
VREF+
ADC AIN0–AIN3
GAIN
BIAS
+5ANA
0.01µ
10K 1%
10K 1%
U3
U2
VREF+
INPUT
REF
+5ANA
RP2
+5ANA
Channel
CH0
CH1
CH2
CH3
Bias
R2
R4
R6
R8
Gain
R1
R3
R5
R7
R8
R7
CH3
R6
R5
CH2
R4
R3
CH1
R2
R1
CH0
The factory defaults for the gain and bias resistors are 2370 Ω
and 39.2 kΩ respectively, giving an input range of 0–10V.
Excitation Resistors
Some transducers (such as thermistors) require excitation resis-
tors. You can install excitation resistors in the RP2 sockets. You
can use a resistor pack or individual resistors:
CH3
+5V
CH2
+5V
CH1
+5V
CH0
+5V
RP2
RP2
RP2
RP2
H1