BASEstartm Open DAS
for Allen-Bradley Data Highwaytm
on OpenVMStm
Installation and User's Guide
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Figure 3-34 shows the structure of a legal Block-Transfer Read/Write Control data table address for the PLC-5/250. Figure 3-35 shows a PLC-5/250 Block-Transfer Read/Write Control structure.

Table 3-22 shows examples of legal Block-Transfer Read/Write Control data table addresses for the PLC-5/250.

Figure 3-34 PLC-5 / 250 Block-Transfer Read / Write Control Address Format

Figure 3-35 PLC-5 / 250 Block-Transfer Read / Write Control Structure

Table 3-22 Example PLC-5 / 250 Block-Transfer Read / Write Control Addresses
Example Address MMS Type1 Description
BR01:1.DLEN UNSIGNED_16 I/O rack 0, group 1, remote scanner 1, slot 1 done length.
BW16:0.PLEN INTEGER_16 I/O rack 1, group 6, remote scanner 1, slot 1 programmed length.
BR103:1.EN BIT_STRING 2 IO rack 10, group 3, remote scanner 2, slot 1 enable bit.
$BW27:1 Structure 3

UNSIGNED_16
UNSIGNED_16
UNSIGNED_16
UNSIGNED_16
UNSIGNED_16
UNSIGNED_16
UNSIGNED_16
UNSIGNED_16 		All of Block-Transfer Write Control for I/O
rack 2, group 7, remote scanner 1, slot 1.
Error code/status bits.
Done/programmed length.
Time stamp.
Current/programmed time-out.
File number/file offset.
Reserved.
BT directory offset.
BT directory length.

1Arrays are not supported for structures other than ASCII strings.
2Control bits should be treated as read only and modified only under PLC program control. Modifying these bits from a computer can give unpredictable results.
3Write operations are not allowed to Block-Transfer Read/Write Control structures.

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