Siemens SM 338 - 3 Installation

17
Product Information on the Reference Manual Programmable Logic Controllers S7-300 Module Data Release 3
A5E00409892-01
1.1.7 Technical Specifications of the 338; POS-INPUT
Dimensions and Weight
Dimensions B x H x T
(mm)
40 x 125 x 120
Weight Approx. 235 g
Voltages, Currents, Potentials
Rated load voltage L+
• Range
• Reverse polarity
protection
24 VDC
20.4 ... 28.8 V
No
Isolation no, only against shield
Permitted potential
difference
• between input
(M connection) and
central grounding point
of the CPU
1 VDC
Encoder supply
• Output voltage
• Output current
L+ –0.8 V
max. 900 mA, short
circuit–proof
Current dissipation
• From the backplane
bus
• From the load voltage
L+ (no load)
max. 160 mA
max. 10 mA
Power dissipation of the
module
typ. 3 W
Encoder inputs POS INPUT 0 to 2
Position decoding absolute
Difference signals for SSI
data and SSI clock
according to RS422
Data transfer rate and cable
length of absolute value
encoders (twisted pair and
shielded)
• 125 kHz max. 320 m
• 250 kHz max. 160 m
• 500 kHz max. 60 m
• 1 MHz max. 20 m
Message duration of the
SSI transmission
• 125 kHz
• 250 kHz
• 500 kHz
• 1 MHz
13 bits 21 bits 25 bits
112 ms 176 ms 208 m s
56 ms 88 ms 104 ms
28 ms 44 ms 52 ms
14 ms 22 ms 26 ms
Monoflop time
2
16 ms, 32 ms, 48 ms, 64 ms
Digital inputs DI 0, DI 1
Isolation no, only against shield
Input voltage 0-Signal: –3 V ... 5 V
1-Signal: 11 V ... 30.2 V
Input current 0-Signal: v2 mA
(quiescent current)
1-Signal: 9 mA (typ.)
Input delay 0 > 1: max. 300 ms
1 > 0: max. 300 ms
Maximum repeat frequency 1 kHz
Connection of a two–wire
BEROS, type 2
Possible
Shielded line length 600 m
Unshielded line length 32 m
Status, Interrupts, Diagnostics
Interrupts
• Diagnostic interrupt Parameters can be
assigned
Status display of digital
inputs
Group error/fault
LED (green)
LED (red)
Inaccuracy of the encoder value
Free running encoder value acquisition
(Standard Mode)
• Maximum age
1)
(2 × Message duration)
+ monoflop time
+ 580 ms
• Minimum age
1)
Message duration
+ 130 ms
• Jitter
Message duration
+ monoflop time
+ 450 ms
Update rate Evaluation of the message
every 450 ms
Free–wheeling sensor value detection (Fast Mode)
• Maximum age
1)
(2 × Message duration)
+ monoflop time
+ 400 ms
• Minimum age
1)
Message duration+
100 ms
• Jitter Message duration+
monoflop time + 360 ms
Update rate Evaluation of the message
every 360 ms
Synchronous encoder value acquisition
• Age Encoder value at time T
i
of
the current PROFIBUS DP
cycle