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1MRK 511 418-UEN A
Section 3
3.1
3.1.1
3.1.2
650 series 2.2 IEC
Communication protocol manual
SPA operation principle
Operation principle
The SPA bus uses an asynchronous serial communications protocol (1 start bit, 7
data bits + even parity, 1 stop bit) with data transfer rate up to 38400 bit/s. For
more information on recommended baud rate for each type of IED, refer to
Technical reference manual. Messages on the bus consist of ASCII characters.
Introduction of SPA protocol
The basic construction of the protocol assumes that the slave has no self-initiated
need to talk to the master but the master is aware of the data contained in the slaves
and, consequently, can request required data. In addition, the master can send data
to the slave. Requesting by the master can be performed either by sequenced
polling (for example, for event information) or only on demand.
The master requests slave information using request messages and sends
information to the slave in write messages. Furthermore, the master can send all
slaves in common a broadcast message containing time or other data. The inactive
state of bus transmit and receive lines is a logical "1".
SPA protocol
The tables below specify the SPA addresses for reading data from and writing data
to an IED with the SPA communication protocol implemented.
The SPA addresses for the pulse counter values PCFCNT:1 to PCFCNT:16 are
found in table 1.
Table 1:
SPA addresses for the PCFCNT function
Function block
SPA address CNT_VAL
PCFCNT:1
6-O-2788
PCFCNT:2
6-O-2794
PCFCNT:3
6-O-2800
PCFCNT:4
6-O-2806
PCFCNT:5
6-O-2812
PCFCNT:6
6-O-2818
PCFCNT:7
6-O-2824
PCFCNT:8
6-O-2830
PCFCNT:9
6-O-2836
Table continues on next page
Section 3
SPA operation principle
SPA address NEW_VAL
6-O-2787
6-O-2793
6-O-2799
6-O-2805
6-O-2811
6-O-2817
6-O-2823
6-O-2829
6-O-2835
IP14401-1 v3
M11880-3 v2
M11880-7 v2
M11880-10 v5
13
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