Communication Between Communication Module, Reader (With Rs422 Interface) And Transponder - Siemens SIMATIC RF300 System Manual

4.1.10 Communication between communication module, reader (with RS422 interface)
and transponder
Communication between the communication module, reader and transponder takes place
asynchronously through the RS422 interface. Depending on the communication module
(ASM) used, transmission rates of 19200 bytes, 57600 bytes or 115200 bytes 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, 09/2007, J31069 D0166-U001-A5-7618
= 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
33