Micromod Micro-DCI: 53MC5000 PLC AND PRINTER INTERFACES - Manual (Page 40)

Table 4-5. Allen-Bradley PLC Write Control Bytes
Title Definition DDI-A DDI-B Set
By
De-
fault
PLC Address It is the address of the PLC to be accessed. B674 B650 User 0
Starting PLC Memory
Address (Low) The two byte PLC memory address that
states where to start writing data into the
PLC memory. Each byte is a decimal
number; however, both bytes together
function as a 16 bit unsigned binary integer
(see Allen-Bradley Read Control Bytes for
example. The value provided in the
example may have to be doubled and
must be an even number for some byte
address oriented Allen-Bradley PLC’s.
Generally, the SLC500 is word address
oriented and other Allen-Bradley models
are byte address oriented. Reference the
appropriate Allen-Bradley
documentation.) B675 B651 User 0
Starting PLC Memory
Address (High) B676 B652 User 0
Number of L-Words
to Write The number of L-words that are to be
written to the PLC. B677 B653 User 0
Number of C-Words
to Write The number of C-words that are to be
written to the PLC. B678 B654 User 0
Write Command Only 0 (Protected Write) or 8 (Unprotected
Write) are acceptable entries. B679 B655 User 0
PLC Error Code*
(Reply Status) The status codes are reported in decimal;
however, they are listed in hexadecimal in
the PLC manual. 255 = no reply; 00 =
Success - No Error. See the PLC book for
the Remote STS (Status) Error Codes. B681 B657 Soft-
ware 0
Communications
Error* 0 = no errors. 255 = timeout error - a
timeout error indicates no response came
back from the PLC. 254 = bad checksum
(CRC) - a bad checksum indicates even
though the frame was formatted properly,
the data can not be used. 253 = bad
message - bad message indicates that
errors were found in the predictable portion
of the message from the PLC. 252 and 251
= PCS hardware malfunction. B682 B658 Soft-
ware 0
Error Count* This byte is a running total of PLC Error
Code responses that are not 00 (Success -
No Error) and non-zero Communications
Error Codes. B683 B659 Soft-
ware 0
*User can reset by writing zeros into the datapoints.
53MC9015 53MC5000 PLC and Printer Interfaces
4-6
ALLEN