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
+5ANA
GND
CH3
CH2
GND
CH1
CH0
GND
The four conditioned channels appear on Wago connector H1,
pictured above, along with +5V analog and GND. The seven un-
conditioned channels (CH4–CH10) have pull-down resistors so
the inputs do not float when unconnected.
ADC
U3
CH[4–10]
10K
AIN[4–10]
VREF+
+5ANA
H2
GND AIN10
GND AIN9
GND AIN8
GND AIN7
GND AIN6
VREF+ AIN5
+5ANA AIN4
2
4
6
8
10
12
14
1
3
5
7
9
11
13
The seven unconditioned channels appear on header H2, along
with +5V analog, VREF+, and GND.
Modes of Operation
The ADC4 can operate in absolute mode or ratiometric mode,
and comes from the factory set to operate in absolute mode.
This mode compares the input signal against a very accurate
fixed voltage reference
In ratiometric mode, the voltage reference, and the sampled
voltage use the same power source. When power fluctuates,
both the voltage reference and the sample show the same fluc-
tuations and errors are minimized.
To use the ADC4 in ratiometric mode, place jumpers on pins 2
and 3 of both J1 and J2. To use the ADC4 in absolute mode,
place jumpers on pins 1 and 2 of both J1 and J2.
J2
Absolute
1
J1
J2
Ratiometric
1
J1
EEPROM
The ADC4 has an EEPROM that stores calibration constants for
channels CH0–CH3 (the four conditioned channels). The chan-
nels are calibrated at the factory. You can recalibrate these four
channels at any time. You can write-protect the EEPROM. Set
jumper J3 according to this figure:
J3
Write-protect Write-enable
1
J3
1
Power
The ADC4 has a 5V regulator to provide a clean 5V to the
board’s analog circuitry. Digital circutry on the board uses +5V
from the PLCBus. You must supply 24VDC (+V for a 24-volt
ADC4 board) or 12VDC (+V for a 12-volt ADC4 board).