2--1 AD101 Analog Input Modules
There are two settings necessary for this Module: the operation mode and
the input ranges (offset and gain) for each input point
Select either two-word or four-word operation. If you select two-word opera-
tion, data is transferred between the Analog Input Module and PLC using the
I/O READ and I/O WRITE instructions, WRIT(87) and READ(88). If you se-
lect four-word operation, data is transferred between the Analog Input Mod-
ule and PLC via the MOVE instruction, MOV(21).
Use of WRIT(87) and READ(88) will simplify programming and shorten the
time required to access analog input data.
The switch for this setting is on the back of the Module and will not be acces-
sible while the Module is mounted to a Rack. Be sure to set this switch before
mounting the Module to the PLC. The setting of the switch is read when the
PLC power is turned ON.
Caution Only the following C120 and C500 CPUs are equipped with WRIT(87) and
READ(88), which are required for two-word operation: 3G2C4-SC023-E and
3G2C3-CPU11-EV1 With all other C120 and C500 CPUs, you must use
four-word operation. These instructions are supported by all C1000H and
C2000H CPUs. Two-word operation is not possible if the Analog I/O Module
is mounted to a Slave Rack in a Remote I/O System, regardless of the CPU.
Four-word operation
Two-word operation
Back of Module
Each input point is set with an offset (minimum) of 1 V (4 mA) and a gain
(maximum) of 5 V ( 20 mA) at the factory. Use the following procedure to
change these settings if necessary. The offset and gain can be set to any-
where between 0 and 10 V (0 and 20 mA) as long as the gain is greater than
the offset. (Refer to
Section 3 Operation
for details on AD conversion.)
Caution If an offset is set below 0 V (0 mA), the binary-converted value will be locked
at 000hex; if a gain is set above 10 V (20 mA), the binary-converted value will
be locked at FFFhex for voltage inputs, but not for current inputs.
Operation Mode
Input Ranges
Section 2--1
