ProSoft Technology MVI94-DNP - Manual (Page 84)

Reference MVI94-DNP ♦ Flex I/O
User Manual DNP 3.0 Server over Ethernet Communication Module
Page 84 of 131 ProSoft Technology, Inc.
December 17, 2010
CROB Control Block for Digital Outputs (Block 9901)
The CROB (Control Relay Output Block) controls a digital output on an IED unit
connected to a master port under program control. This block provides more
control than the binary output control offered in the command list. The selected
point can use the pulse on/off feature of the DNP protocol using this block. Refer
to the Basic 4 documentation for a full discussion of the CROB object and its
functionality. The structure of the block sent from the processor to the module is
shown in the following table.
Word Offset in Block Data Field(s) Description
0 Block ID This field contains the block identification code of
9901 for the block.
1 Slave Address This is the IED node address for the slave to
consider on the network.
2 Function Function codes 3, 5 and 6 supported. Function
code 4 is automatically sent after a successful
function 3.
3 Address in Slave Point in IED to consider with the CROB.
4 Control Code This is a standard DNP protocol control code
byte (see description below).
5 Pulse Count This parameter specifies the number of pulses to
generate for pulse output control. This parameter
has a range of 0 to 255 as the value is a byte
parameter in the CROB. If a value of zero is
entered, the operation will not execute.
6 Pulse On/Off Time This parameter specifies the on-time and off-time
intervals for pulse control. The same time value is
used for both parameters in the constructed
CROB message.
The Control Code field of the block defines the method of output control. This bit-
mapped value has the following definition:
Bits Definitions Description
0 to 3 Code These bits determine the control operation to be
performed by the command: 0=No operation,
1=Pulse on, 2=Pulse off, 3=Latch on and 4=Latch
off. All other values are undefined in the DNP
protocol.
4 Queue 0=Normal (execute once), 1=Requeue (place at
end of queue after operation).
5 Clear This parameter clears the queue. If the value is
set to zero, the queue is not affected. If the value
is set to 1, the queue will be cleared.
6 to 7 Trip/Close These two bits select the trip or close relay. For
close relay control, set the bits to 01. For trip
relay control, set the bits to 10. A value of 00 for
the bits is used for single point control of normal
digital output points.
When the module receives this block, it will place the request in the command
queue as long as there is room in the queue for the command. This will cause
the command to be executed at a high priority. The module does not send a
response message back to the processor for this block.