ProSoft Technology MVI56-101S - Manual (Page 101)

MVI56-101S ♦ ControlLogix Platform Reference
IEC 60870-5-101 Slave Communication Module User Manual
ProSoft Technology, Inc. Page 101 of 193
August 2, 2011
Read Block
This block transfers IEC output (control) data sent from the remote IEC 104
Client through the module to the ControlLogix processor. The following table
outlines the structure of data contained in the input image of a normal Read
Block.
Offset Description Length
0 Reserved 1
1 Write Block ID 1
2 to 201 Read Data 200
202 Program Scan Counter 1
203 to 204 Product Code 2
205 to 206 Product Version 2
207 to 208 Operating System 2
209 to 210 Run Number 2
211 to 214 Data Transfer Status 4
215 Port Select 1
216 Bad Checksum Count 1
217 Sync Error Count 1
218 Length Error Count 1
219 Timeout Error Count 1
220 RX Frame Count 1
221 TX Frame Count 1
222 to 248 Spare 27
249 Read Block ID 1
The Read Block ID is an index value sent by the module and used by the ladder
logic to determine where the current 200-word block of input data should be
placed in the ControlLogix processor IEC870S.ReadData controller tag array.
Each input data block transfer can move up to 200 words of user application data
(Read Block offsets 2 to 201) from the module to the processor. In addition to
moving user data, the block also contains module status data. This status data is
transferred with each new input image block and can be used for module
diagnostics.