Command Syntax: Pcread; Response Syntax: Pcread - Siemens SIMATIC TI505 386/ATM User Manual

Communicating during PLC Scan: Special Function Cycle (continued)
Command Syntax:
PCREAD
Response Syntax:
PCREAD
5-8 PLC Communications
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PCREAD allows you to read PLC memory. The syntax of a PCREAD
command is as follows.
:pr:memory_type:start_point:count::<cr>
where:
:
is the separating delimiter for the command.
pr is the command syntax for PCREAD.
memory_type
is the memory type: VMEM, WX, WY, TCC, TCP, DSC,
DCP, STW, DCP, KMEM, XREG, YREG, CREG
start_point
is the starting address for the memory type;
ASCII/decimal.
count is the number of data items that you want to read in this
transaction; ASCII/decimal.
:: is the ending delimiter for the command.
<cr>
is the ASCII character 0D HEX denoting the end of the
response transaction.
PCCOMM responds to the PCREAD command in the following format.
:pr:error_code:val_1:val_2:val_n::<cr>
where:
:
is the separating delimiter for the command.
pr is the command response for PCREAD.
error_code
if positive, the number of values read from the PLC
if zero, a bad memory_type, a bad start_point for the
memory_type or a bound count. No words were returned.
if negative, a communications failure with the PLC.
val_1 to val_n are the values returned from the device driver.
::
is the ending delimiter for the command.
<cr> is the ASCII character 0D HEX denoting the end of the
response transaction.
386/ATM Coprocessor User Manual