Section 3 SPA operation principle
3.1 Operation principle
IP14401-1 v3
M11880-3 v2
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.
3.1.1 Introduction of SPA protocol
M11880-7 v2
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".
3.1.2 SPA protocol
M11880-10 v5
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 SPA address NEW_VAL
PCFCNT:1 6-O-2788 6-O-2787
PCFCNT:2 6-O-2794 6-O-2793
PCFCNT:3 6-O-2800 6-O-2799
PCFCNT:4 6-O-2806 6-O-2805
PCFCNT:5 6-O-2812 6-O-2811
PCFCNT:6 6-O-2818 6-O-2817
PCFCNT:7 6-O-2824 6-O-2823
PCFCNT:8 6-O-2830 6-O-2829
PCFCNT:9 6-O-2836 6-O-2835
PCFCNT:10 6-O-2842 6-O-2841
PCFCNT:11 6-O-2848 6-O-2847
PCFCNT:12 6-O-2854 6-O-2853
PCFCNT:13 6-O-2860 6-O-2859
PCFCNT:14 6-O-2866 6-O-2865
PCFCNT:15 6-O-2872 6-O-2871
PCFCNT:16 6-O-2878 6-O-2877
1MRK 511 396-UEN E Section 3
SPA operation principle
SPA, 670 series 11
Communication protocol manual
© Copyright 2017 ABB. All rights reserved
To Next Page
Loading...
