Siemens SIMATIC S5 CP 521 Manual page 16

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In In ASCII mode, the CP 521 assumes a peripheral device (terminal, modem,
enables you to transmit message frames between the CPU and an peripheral
device connected to the CP 521. Maximum data throughput is six bytes of useful
data per two program scans. This means that a maximum of 60 bytes/s can be
transmitted given a program scan time (OB 1 ) of, for example, 50 ms.
The CP 521 can be used to
The CP 521 can be used to
. Send fixed-length message frames
. Send variable-length message frames
Receive fixed-length message frames
Receive variable-length message frames
You can define the transmission mode in the user program.
The time from the module's own real-time clock can also be used in ASCII mode
for tasks in the user program requiring the date and time of day.
Figure 1-2. Complete Configuration: Point-To-Point Connection
GWA 4NEB 812 6030-02b
System Overview
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