Siemens SIMATIC S5-90U System Manual page 533

S5-90U/S5-95U
The maximum data flow rate is 6 bytes of user data per 2 program cycles; i.e. at a program cycle
time of, for example, 50 ms a maximum of 60 bytes per second can be transmitted.
The following terminals and communications devices can be used as I/O devices:
• Keyboard
• Terminal
• Another CP 521 SI
• CP 523
• S5-95U with second serial interface
• CP 524/CP 525-2 (in connection with special driver 6ES5 897-2AB11)
• CPU 944 (with ASCII driver, 3964(R) driver)
• Other I/O devices with serial interface, e.g. bar code readers
Which of the I/O devices and transmission modes are used depends on the intended application of
data transmission. In the bidirectional data exchange mode of the module you are, for example, able
to network programmable controllers (point-to-point link).
I/O devices and CP 521 SI are connected with each other via a serial interface. Either a passive
TTY interface or a 24 V voltage interface are available (programmable).
Parameterizing (matching) of the I/O interface and configuring of the message texts are supported by
the DB editor of programmers. The parameters of the I/O interface are stored either on a memory
submodule in DB1 or are directly transmitted in the user program. The CP 521 SI can be
programmed and operated wihtout the COM software.
Integrated Real-Time Clock
The CP 521 SI has it's own real-time clock which is battery-backed when the module is in the de-
energized state. Independent of the type of function selected for the CP 521 SI, the clock data can
be read from the CPU and can be used in the user program for date and time-dependent tasks.
Installation
As other I/O modules, the CP 521 SI is mounted on the bus unit.
• With the S5-90U, a maximum of 2 CP 521 SI modules (limited by current consumption) can be
plugged in only at slots 0 to 5.
• With the S5-95U, a maximum of 7 CP 521 SI modules (limited by current consumption) can be
plugged in only at slots 0 to 7.
• The module has no connection to the terminal block.
Adressing
The CP 521 SI is addressed like a 4-channel analog module.
EWA 4NEB 812 6115-02b
Function Modules
16-65