6ES5521-8MA21
Siemens Simatic S5 CP521 Communications Processor Module with Serial Interface for S5-90U/95U/100U

The Siemens 6ES5 521-8MA21 is a CP 521 SI (Serial Interface) communications module for Simatic S5 PLCs. It is a powerful I/O module with its own central processor. The following is an overview of the module's mode of operation.

Features of the 6ES5521-8MA21

Function

The CP 521 SI can be used for unidirectional and bidirectional data exchange.

Unidirectional Data Exchange

For unidirectional data traffic, the CP 521 SI is provided with a printer driver. If the printer driver is used, the following must be connected to the serial interface of the CP 521 SI:

• A printer with TTY interface (active) or
• A printer with V.24 (RS 232C) interface
• This enables you to log process states and process disturbances. The output of messages on the printer does not extend the response time of the programmable controller
• The following messages and texts can be output:
• Message texts, which you have configured on a memory submodule in data blocks DB 2 to 63
• Time of day and date, which are provided by the module's own clock
• Values for variables which are transmitted to the CP 521 SI via the I/O bus
• The message texts are stored on an EPROM or EEPROM memory submodule (up to 8/16 Kbytes)

Bidirectional Data Exchange

The following drivers are implemented for the bidirectional data exchange:

• ASCII driver, transparent
• ASCII driver, interpreting
• 3964(R) driver
• SINEC L1 driver, master (point–to–point link)
• SINEC L1 driver, slave
• Terminal driver
• The use of these drivers enables the transmission of data frames between the CPU and an I/O device connected to the CP 521 SI
• 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
• 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 device and CP 521 SI are connected with each other via a serial interface
• Either a passive TTY interface or a V.24 voltage interface are available (programmable)
• Parameterising (matching) of the I/O interface and configuring of the message texts are supported by the DB editor of the programmers. The parameters of the I/O interface are stored either on the memory submodule in DB1 or are directly transmitted in the user program. The CP 521 SI can be programmed and operated without the COM software.

Integrated Real-Time Clock

The CP 521 SI has its own real–time clock which is battery–backed when the module is in the de–energised 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 BASIC is mounted on the bus unit.

• The module can be plugged in only at slots 0 to 7
• The module has no connection to the terminal block
• The printer is connected to the module with a 25–pin sub D connector

Addressing

The CP 521 BASIC is addressed like a 4–channel analog module.

6ES5521-8MA21 Technical Specifications