Siemens S7-200PLC Manual de usuario descargar pdf (Pagina 19)

Appendix 1 – Syntax of S7-200 tag addresses

Chapter 8.

8.4 Examples

Address Pointing to

MW4 the Word at address 4 (in bytes) in the Internal Memory

HCL1 the High Speed Counter number 1, read it as Signed Word

AQW5 the Word at address 5 (in bytes) in the Analog Output zone

IB3 the Byte at address 3 (in bytes) in the Discrete Inputs zone

I5#2 the bit 2 from the Byte (read ’Bit access modifer’ note below) at address 5

in the Discrete Inputs zone

Table – Examples of register addresses for S7-200

8.5 Bit access modifier

For Memory Types M, SM, V, I and Q, it is possible to access a single bit.

A [#x] must be appended to the Value Name.

As the address refers to a starting byte, the Bit index goes only from 0 to 7. No other Modifier

than B is allowed.

The syntax can be used for reading Bits and for writing them as well.

Examples:

Valid: AQ10#5 is OK because it represents bit 5 of Byte 10 in the Analog Output zone

Invalid: IW5#2 is wrong because there is a Modifier

I5#10 is wrong because the Bit number is greater than 7

8.6 Status register

The STATUS Tag is a special Tag that returns information about the current state of the

communication for a given device. The status Tag ValueName is composed of:

Status[Global Device Address]

Possible values of the Status tags:

Status

Value Corresponds to

0 Communication not initialized. Status UNKNOWN.

If no Tag is polled on that device address, the communication status is

unknown.

1 Communication OK

2 Communication NOT OK

Table – Tag status value meaning

• You can define a status Tag for each PLC used.

Polling Data Registers from Siemens S7-200 PLC Series (How to) Page 19/21

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Siemens S7-200PLC Manual de usuario Pagina 19