Analog Modules
4-155
Programmable Logic Controllers S7-300 Module Data
A5E00105505-03
Technical specifications of the SM 331; AI 2 x 12 bits
Dimensions and Weight
Dimensions W x H x D
(in millimeters)
40 x 125 x 117
Weight Approx. 250 g
Data for Specific Module
Supports clocked operation No
Number of inputs
• For resistance-type
sensor
2
1
Length of cable
• Shielded
max. 200 m
max. 50 m at 80 mV and
thermocouples
Voltages, Currents, Potentials
Rated supply voltage of the
electronics L +
24 VDC
• Reverse polarity
protection
Yes
Power supply of the
transmitters
• Supply current max. 60 mA (per channel)
• Short-circuit-proof Yes
Constant current for
resistance-type sensor
typ. 1.67 mA
Isolation
• Between channels and
backplane bus
Yes
• Between channels and
power supply of the
electronics
– Not for 2-wire
transmitter
Yes
Permitted potential
difference
• Between inputs and
M
ANA
(U
CM
)
– At signal = 0 V
2.5 VDC
• Between M
ANA
and
M
internal
(U
ISO
)
75 VDC / 60 VAC
Insulation tested with 500 VDC
Current consumption
• From the backplane bus max. 50 mA
• From the backplane bus
L +
max. 30 mA (without
two-wire transmitter)
Power dissipation of the
module
typ. 1.3 W
Analog value generation
Measuring principle Integrating
Integration time/conversion
time/ resolution (per
channel)
• Parameters can be
assigned
Yes
• Integration time in
milliseconds
2.5 16
2
/
3
20 100
• Basic conversion time
including Integration
time in milliseconds
6 34 44 204
Additional conversion
time for measuring
resistance, in ms
or
11 11
Additional conversion
time for open-circuit
monitoring, in ms
or
10 10 10 10
Additional conversion
time for measuring
resistance and
open-circuit monitoring,
in ms
16 16 16 16
• Resolution in bits (incl.
overrange)
9
bits
12
bits
12
bits
14
bits
• Noise suppression for
frequency f1 in Hz
400 60 50 10
• Basic response time of
module, in ms (all
channels enabled)
6 34 44 204
Smoothing of the measured
values
None