© Arun Microelectronics Ltd 2020. All rights reserved
Page 31
14.4.
Host Computer Commands
The host computer sends commands in the following format:
First byte:
‘
*
’
(0x2A)
Second byte:
Command character. All commands are represented by a single character.
Third byte:
Ignored on NGC3 (c
haracter ‘0’ to ‘8’ (0x30 to 0x38) or ‘X’ (0x58). This ensures
compatibility with PGC1, which had a multi-drop capability where instruments were
addressable (all the examples below
use ‘0’)
.
Optional parameter:
Additional command parameters, single ASCII characters.
14.5.
NGC3 Response
The NGC3 responds to the <poll> command with the
state byte
and
error byte
, followed by a CR-LF (0x0D, 0x0A). The
NGC3 responds to the <status> command as detailed on the following pages. All other commands are processed by the
NGC3 without a response being issued.
14.6.
Timing of Next Command
Following the transmission of a <poll> or <status> command, the host computer should not begin transmitting a new
command until a CR-LF has been received, signalling the end of transmission. It is not necessary to poll the NGC3 more
than 4 times per second, and we strongly recommend that a delay of at least 100 ms is implemented before the next report
request. The response to commands is typically less than 1 second.
14.7.
State & Error byte coding
State byte:
Bits 3-0 :
Instrument type (00102
–
NGC3)
Bit 4
:
0 = local mode, 1 = remote mode
Bit 5
:
1
Bit 6
:
0 = IG 1 selected, 1 = IG 2 selected
Bit 7
:
Ion Gauge disconnected
Error byte:
Bit 0
:
gauge - specific error
Bit 1
:
over temperature trip
Bit 2
:
bake error
Bit 3
:
temperature warning
Bit 4
:
0
Bit 5
:
0
Bit 6
:
1
The value in the error byte is maintained until reset by a <reset error> command.
Содержание NGC3
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