West Control Solutions KS 800 ISO1745 Interface Manual - Manual (Page 6)

2 Interface protocol
2.1 Protocol layer 1
Bus connection is physical:
w via the PC interface as a TTL signal (COM 1)
w via an RS485/422 connection (COM 2) with version KS800-RS.
2.1.1 Data format
The following transmission format, fixed, must be used:
w 1 start bit,
w 7 bits ASCII value or 7 bits binary
w 1 parity bit (EVEN)
w 1 stop bit
LSB is transmitted first, MSB is parity bit.
2.1.2 Baud rate
The Baud rate for the serial interface is adjustable. The following Baud rates are available:
w 2400 Baud
w 4800 Baud
w 9600 Baud
w 19200 Baud
2.1.3 Parity
Parity detection is fixed to EVEN.
2.1.4 Addressing
KS 800 can be operated together with KS40, KS50, KS90, KS92, KS94 , KS98, KS4580,
DIGITAL 280/380 and PRO 96 and the ICS 90 and ITS 90 systems at the same bus. Decisive for instrument
selection is the address (2 bytes).
The KS 800 (0...99) address is adjusted via the “KS800 Engineering Tool” (general instrument settings Ä
communication Ä address).
2.2 Protocol layer 2
A fixed master/slave principle is used, whereby KS800 is always slave. Transmission control
(communication start and cancelation by EOT) is always by the master.
Two communication services are available:
q for data sending: SDA (Send Data with Acknowledge)
, acknowledged by KS 800
Data flow direction : master r KS 800
a) Master EOT <address> STX <data> ETX BCC
b) KS 800 ACK NAK
1)
no reaction
2)
c) Master
EOT
or continue with a
repeat a,
or EOT
(1)
after timeout:
EOT or continue with a
(2)
Interface protocol
9499 040 49411 6 990924
1) Possible after disturbance of transmission or after sending inadmissible data.
2) Possible after KS 800 failure, bus failare or faulty address specification.