4-5
Section
Analog Input Functions
81
4-5
Analog Input Functions
4-5-1 Setting Inputs and Signal Ranges
The Analog I/O Unit only converts analog inputs specified by input numbers 1
and 2. In order to specify the analog inputs to be used, turn ON from a Peripheral
Device the DM bits shown in the following diagram.
15
14
13
12
11
10
09
08
07
06
05
04
03
02
01
00
Bit
DM (m)
Input 2
Input 1
0: Do not use
1: Use
The analog input sampling interval can be shortened by setting any unused input
numbers to 0.
Sampling interval = (1 ms) x (Number of inputs used) +(1ms) x (Number of
outputs used (see note a)) (+ (0.5ms) x (Number of loops used (see note b)))
Note
a) Refer to
4-6 Analog Output Functions
for output settings.
b) Only when using the ratio conversion function.
For the DM word addresses, m = 1000 + 100 x unit number (Units #A to #F = Unit
numbers 10 to 15).
Any of four types of input signal range can be selected for each of the eight inputs
(input numbers 1 and 2). In order to specify the input signal range for each input,
set from a Peripheral Device the DM bits shown in the following diagram.
15
14
13
12
11
10
09
08
07
06
05
04
03
02
01
00
Bit
DM (m+1)
Input 2
Input 1
00: -10 to +10 V
01: 0 to +10 V
10: 1 to 5 V / 4 to 20 mA
11: Same as 10 above.
Note
1. For the DM word addresses, m = 1000 + 100 x unit number (Units #A to #F =
Unit numbers 10 to 15).
2. The I/O signal range of “1 to 5 V” or “4 to 20 mA” is switched according to the
input terminal connections.
3. After making the DM settings from a Peripheral Device, it will be necessary
to either power up the PC again or turn ON the Special I/O Unit Restart Bit in
order to transfer the contents of the DM settings to the Special I/O Unit. For
details regarding the Special I/O Unit Restart Bit, refer to
4-9-4 Restarting
Special I/O Units
.
Input Numbers
Input Signal Range
