Siemens SIMATIC User Manual

Other signal modules
7.4 Position decoder module SM 338; POS-INPUT; (6ES7338-4BC01-0AB0)
S7-300 Module data
506 Manual, 06/2017, A5E00105505-AJ
Parameters
Range of values
Note
Monoflop time
1),2),3)
16 µs; 32 µs; 48 µs;
64 µs
The monoflop time represents the minimum inter-
val between two SSI frames.
The configured monoflop time must be greater
than the monoflop time of the absolute value
encoder.
Scaling
• Places
• Steps per revolution
4
0
to 12
2 to
8192
Scaling right-aligns the encoder value in the ad-
dress space; irrelevant places are discarded.
Enabling the Freeze function
off
; 0; 1 Definition of the digital input that initiates freezing
of the encoder value at the positive edge.
1
Refer to the technical specifications of the absolute value encoder
2
The monoflop time represents the interval between two SSI frames. The configured mo
n-
oflop time must be greater than the mono
flop time of the absolute value encoder (see the
technical data of the manufacturer). The time 2 x
(1 / transmission rate) is added to the
value set in HW Config. A transmission rate of 125 kHz and configured monoflop time of
16 µs sets an effective monoflop time of 32 µs.
3
Restriction of the monoflop time of the absolute value encoder:
(1 / transmission rate) < monoflop time of the absolute value encoder < 64 µs + 2 x (1 /
transmission rate)
4
to powers of two
Note
Please note that in asynchronous
mode, the transmission rate and monoflop time affect the
accuracy and update quality of the encoder values. In isochronous mode, the transmission
rate and monoflop time have an influence on the accuracy of the freeze function.

Siemens SIMATIC Specifications

General

Product type designation	SIMATIC
CPU	Varies by model
Memory	Varies by model
Input/Output	Varies by model
Communication	Varies by model
Programming Language	STEP 7
Operating Temperature	0°C to 60°C (varies by model)
Protection Class	IP20
Category	Programmable Logic Controller (PLC)