Siemens simatic c7-621 - Page 96

7-14
C7-621 / C7-621 AS-i Control Systems
C79000-G7076-C621-01
The following table contains the technical data of the analog inputs of the C7
CPU.
Module-Specific Data
Number of inputs 4
Cable length
S Shielded max. 100 m
Voltages, Currents, Potentials
Permitted potential difference
S Between inputs and M
ANA
(U
CM
)
DC 1.0 V
Analog Value Formation
Measuring principle
Conversion time/resolution
(per channel)
S Base conversion time
S Resolution (including
overflow range)
Instantaneous value
encoding (successive
approximation)
100 ms
11 bits + sign
Noise Suppression, Error Limits
Noise voltage suppression
S Common mode voltage
(U
CM
< 1.0 V)
> 40 dB
Crosstalk between inputs > 60 dB
Error limit (in the entire
temperature range related to
the input range)
S Voltage input
S Current input
" 1.0 %
" 1.0 %
Noise Suppression, Error Limits, continued
Basic error limit (operational
limit at 25 °C relative to input
range)
S Voltage input
S Current input
" 0.9 %
" 0.8 %
Temperature error (relative to
input range)
" 0.01 %/K
Linearity error (relative to
input range)
" 0.06 %
Reproducibility accuracy (in
settled state at 25 °C, relative
to input range)
" 0.06 %
Status, Interrupts; Diagnostics
Interrupts none
Diagnostic functions none
Data for Selecting a Sensor
Input ranges
(rated values)/input resistance
S Voltage
S Current
" 10 V/50 kW
" 20 mA/105.5 W
Permitted input voltage for
voltage input (destruction
limit)
max. 30 V permanent;
38 V for max. 1 s
(pulse duty factor
1:20)
Permitted input current for
current input (destruction
limit)
34 mA
Connection of sensors
S for voltage measurement
S for current measurement
as 2-wire transducer
as 4-wire transducer
possible
not possible
possible
Analog Input
C7-621 Analog I/Os