Communication Between Communication Module, Reader And Transponder; Rf300 - Siemens SIMATIC RF300 System Manual

t
v
t :
V:
t :
K
4.1.8

Communication between communication module, reader and transponder

Communication between the communication module, reader and transponder takes place
asynchronously through the RS422 interface. Depending on the communication module
(ASM) used, transfer rates of 19200 baud, 57600 baud or 115200 baud can be selected.
Calculation of the communication time for interference-free transfer
The communication time for fault-free data transfer is calculated as follows:
t
K
If the transmission is interrupted briefly due to external interference, the communication
module automatically continues the command.
Calculation of the maximum amount of user data
The maximum amount of user data is calculated as follows:
t :
k
t :
v
n:
n
max
t
byte
K
:
SIMATIC RF300
System Manual, 11/2009 - Zwischenstand 17.09.2009, A5E01642529-04
t ≥
K
Dwell time of the data memory within the field of the reader
Communication time between transponder and communication module
= K t + ⋅ n
(n >1)
Byte
Communication time between communication module, reader and transponder
Dwell time
Amount of user data in bytes
: Max. amount of user data in bytes in dynamic mode
: Transmission time for 1 byte
Constant; the constant is an internal system time. This contains the time for power
buildup on the transponder and for command transfer
RF300 system planning
4.1 Fundamentals of application planning
37