Edwards SCU-800 User Manual

SCU-800 Control Unit for Turbomolecular Pump
MT-49E-101-G
Page 71
5
SERIAL COMMUNICATION
PROTOCOL
ASCII
Stx
0
0
1
#
Etx
LRC
HEX
02
30
30
31
23
03
EC
However, when the MSB (most significant bit) is always 0 when data length is 7 bits, LRC is set to
6C
hex
.
5.3.7 Error control
1. Transmit the transmission frame repeatedly from the PC when the SIM transmits "Nak" (parity
check error). When the SIM receives "Nak" from the PC, the transmission frame is transmitted
again. This operation is repeated up to 5 times.
2. The SIM transmits "Ack" or "Nak" to the PC after the completion of communication command
reception. When the PC cannot receive "Ack" or "NaK" after 2 second, retransmit the
transmission frame from the PC.
When these communication statuses occur repeatedly, display to an error message or start the error
routine on the PC.

Edwards SCU-800 Specifications

General

Brand	Edwards
Model	SCU-800
Category	Control Unit
Language	English