Read Services - ABB Protronic 100 Manual

Description of the Read Service
The read service requires 4 bytes in the output data for the
request, and 10 bytes in the input data for the response. This
structure is defined directly in the device database file as a
module. A read job is written in the output data, the result is
returned in the input data. --
Output data (request) telegram:
Byte 0 Byte 1 Byte 2 Byte 3
Word 1
Service Polling Variable index
=0x20 number -
Service Polling Variable Variable
=0x20 number - index index
Lowbyte - Highbyte -
Table 9
Input data (response) telegram
Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 Byte 7 Byte 8 Byte 9
Word 1
Service Polling Variable index Status
=0x20 No. -
Service Polling Var. Var. Status
=0x20 No. - index index
Lowbyte Highbyt
-- e--
Table 10
The response becomes valid at the time when the polling number
has the same value in the response telegram as in the request
telegram.-
Description of the individual entries:
Entry Data type Description
Service Byte
Polling number Byte
Variable
index 16-bit integer Index of the variable that is to be
20 Operation
Error 1 to 4 data bytes
Error 1 to 4 data bytes
ID for the read service
(Index = 0x20)
When this value is changed, the
read job will be executed. - As long
as this value remains unchanged,
the read job is not executed any
longer.- Value 0 is permissible.- It
is useful to activate a read job by
incrementing the value by 1. - A
one byte overflow from 0xFF to
0x00 is not a problem. -
read. - Refer to
"Addressing the Data" for a list of
possible indices.
Variable
index
Lowbyte Byte
Variable
index
Highbyte Byte
Status Byte
Error Byte
1 to 4
Data bytes 4 bytesData block for REAL, DINT, TIME, INT and
Example
The output value of the 3rd control loop is to be read acyclically.
The required variable .L3_PID_Y_OUT has the variable index
0x0367. The byte value for the polling number must be different
from the byte value used before. A REAL number is read as the
requested value. -
section
Request:
0x20, byte value, 0x0367 (variable index as 16-bit integer)
0x20, byte value, 0x67, 0x03 (variable index in bytes)
Response (if processed without errors):
0x20, byte value, 0x0367, 0x01, 0x00 , 4 bytes for value
(Variable index as 16-bit integer)
0x20, byte value, 0x67, 0x03, 0x01, 0x00, 4 bytes for value
(Variable index in bytes)
The 4 bytes for the values are to be interpreted in accordance
with section "Numerical Formats and Displays". --
The low byte of the 16-bit integer value for
the variable index.--
attached variable index list these
are the 2 right digits of the
hexadecimal number.----
necessary when
system does not allow to define a
16-bit integer. --
The high byte of the 16-bit integer value for
the variable index. -- In the
attached variable index list these
are the 2 digits to the right of
0x....... in the hexadecimal number
format. Only necessary when the
master system does not allow to
define 16-bit integers.------
0x01 is delivered as the status when the
job has been carried out without
errors. - The error field contains
the value 0x00. Otherwise, 0x00 is
delivered as the status. In this
case, the error cause can be
derived from the error field.
Outputs information about the occurred
error, when the status field has the
value 0x00. Error codes:
0x00 No error occurred
0x40Unknown service entered in
the service field. --
0x20Unknown index entered in the
variable index field.-
BOOLean data.
In the
Only
the master