Commreq #11: Read Device Command - GE GFK-2892F User Manual

COMMREQ #11: Read Device Command

To read up to 128 bytes of data from another CPU and place it in the host PLC CPU memory, use the Read
Device command. This causes the Genius Gateway to issue a Read Device datagram. When the requested data
is received, it will automatically be placed in the CPU memory location specified in the Command Block.
Note that while the GCG001 does support this COMMREQ, the Genius devices which respond to such a
COMMREQ are not currently supported by the GCG001.
Command Block for the Read Device Command
Address Command Length
Address +1 No Wait
Address +2 Status Block memory type
Address +3 Status Block offset
Address +4 Idle timeout value
Address +5 Max. communications time
Address +6 Command number
Address +7 PROFINET Device number
Address +8 Genius Device Number
Source Memory Address,
Address +9
bytes 1, 2
Address +10
bytes 3, 4
Program name,
Address +11
characters 1, 2
Address +12
characters 3, 4
Address +13
characters 5, 6
Address +14
characters 7, 8
Block name,
Address +15
characters 1, 2
Address +16
characters 3, 4
Address +17
characters 5, 6
Address +18
characters 7, 8
Source Data length,
Address +19
(in words, bytes, or bits).
Maximum Deposit memory
Address +20
length
Address +21 Deposit Memory type
Address +22 Memory offset
Address +23
Device Memory Addressing
For Series 90 and PACSystems PLCs, Address+9 contains the segment selector value for the memory type
being read. Address+10 contains the zero-based offset into the memory being read.
For legacy devices, use an absolute address, where Address+9 is the least-significant word of the address and
Address+10 is the most-significant word of the address field.
GFK-2892F
Chapter 6. COMMREQ/Data_Init_Comm Programming
18
0
70 (%I), 72 (%Q), 8 (%R), 10 (%AI), 12 (%AQ) or 196 (%W)
Beginning address for the COMMREQ Status Block.
0
0
11
1-255: The device number of the targeted GCG Genius Gateway.
0-31: the SBA of the targeted Genius Device from which data is to be
retrieved.
Specify the location FROM which the requested data will be read.
(It is not necessary to specify a source memory address when sending a
Read Device COMREQ to a computer).
Required to read %P or %L memory in another PLC, otherwise zero.
If the target of the command is NOT a PLC, Address +11 through Address
+18 are ignored; they may contain any value.
Program names are limited to 7 characters. Character 8 and all other
trailing characters MUST be entered as nulls (00h).
Required to read %L memory in a PLC, otherwise zero.
For %P, Address+15 through Address +18 are ignored.
Block names are limited to 7 characters. Character 8 and all other trailing
characters MUST be entered as nulls (00h).
This is the amount of data to be read from the targeted device. When
reading a PLC, data length is defined in bits or words, depending on the
memory type being read. For other types of devices, the length entered
here is as expected by the target device.
The maximum length is equal to 128 bytes.
Memory length needed for the returned data. Value in bits or words
(depends on memory type selected in Address+21 below).
Enter the code representing the CPU Memory Type where the GCG will
deposit the data obtained from the target Genius Device. Use the same
codes as in Address+2.
bytes 1, 2 Starting address within the Deposit Memory type.
bytes 3, 4 (Byte 4 is MSB, Byte 1 is LSB)
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