1MAC052634-MB D
Section 3
Vendor-specific implementation
615/620 series ANSI
29
Communication Protocol Manual
RespType
01 = Unsecured control response
10 = Secured control response
11 = Modbus 03 exception response valid. CMDResultCode is in this case 0. The reason
for the 03 exception is an invalid written value.
Table 19:
CMDResultCode
3.3.8
Event records
The IED creates a Modbus event record when a momentary digital input bit changes its
value. The IED then stores the changed Modbus bit location and value into the Modbus
event record buffer. The event time tag is also stored into the record. The time tag includes
a full time stamp from a year down to milliseconds.
The size of the IED's internal Modbus event record buffer is 500 events. The 500 latest
events are at any time readable from the IED. When the Modbus event record buffer
becomes full, the IED overwrites the oldest event records in the buffer.
Multiple clients support
Several Modbus clients can independently of one another read out Modbus event records
from the IED. The Modbus event buffer keeps track of where in the event buffer the
different clients are reading at the moment. Clients are identified either by the serial port
from where the requests are issued or by the client's IP address in the TCP/IP network. Up
to 25 different IP addresses are memorized by the IED.
Multiple events reading, backwards compatibility
The original 615/620 series event reading concept only allowed reading out one event
structure at a time. In later 615/620 series IED versions this was extended to include up to
10 event structures at a time. Multiple event structures reading adds one Modbus register,
“Num of event records in multiple event reading”, that normally should contain the
amount of event structures to be read. However, it is not necessary to write a “1” into this
register if the client only wants to read one event at a time. This feature provides
backwards compatibility with the original event reading concept.
3.3.8.1
Single event record structure
See Modbus ANSI point list manuals for specific event record structure mappings.
Code
Meaning
0
OK
201
Device in local mode
202
Control operation reserved by another client
203
Select-timeout or Execute/Cancel without select
204
Control operation internally blocked
205
Control operation timed out
250
Other reason
