Mailbox commands, Mailbox structure, Mailbox from plc to gw – ProSoft Technology 5205-104S-PDPS User Manual
Page 63: Mailbox from gw to plc, Example raw database exchange

Protocol Implementation
4205/5205-TS-104S-PDPS ♦ ProLinx Standalone
IEC-60870-5-104 to PDPS Communication Module with Time Stamp
ProSoft Technology, Inc.
Page 63 of 128
July 12, 2007
Mailbox Commands
Start Stop
Direction
Description
100
101
PLC to GW
Event Data
150
151
PLC to GW
Database write transfer
160
161
GW to PLC
Database read transfer
200 200
Both
Set
Time
201 201
Both
Get
Time
202
202
Both
Get Event Buffer Counts
PLC = PROFIBUS master interface in PLC
GW = ProLinx Gateway
NOTES:
The block number for each device must be changed to trigger an operation.
The I/O data area is owned exclusively by only the PLC or GW.
A timeout must be implemented in the PLC in case the GW is not present.
Mailbox Structure
Mailbox From PLC to GW
Start Byte
End Byte
Description
0
0
Block number of data in block
1
1
Block number of data requested
2
198
Data for block
199
199
Block number of data in block
Mailbox From GW to PLC
Start Byte
End Byte
Description
0
0
Block number of data in block
1
1
Block number last requested by PLC
2
198
Data for block
199
199
Block number of data in block
Example Raw Database Exchange
Start Byte
End Byte
Description
0
0
150 (Raw data write)
1
1
160 (Raw data read)
2
3
Start register in database for write
4
5
Number of registers to write (1 to 94)
6
7
Start register in database for read
8
9
Number of registers to read (1 to 96)
10
197
Words to write to the database
198 198
Reserved
199
199
150 (Raw data write)