INFICON BPG400 ATM to Ultra-High Vacuum Gauge - Manual (Page 37)

tina03e1-b (2004-02) BPG400 v1.om
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This interface allows operation of BPG400-SR with part number
353-509 and
353-513
in connection with other devices that are suited for RS485 bus operation.
Two adjustable switching functions are integrated in BPG400-SR. The corre-
sponding relay contacts are available on the sensor cable connector (
→ 21).
Additionally, the relay contact of the switching function A is accessible on the
RS485 interface connector (
→ 24).
The basic sensor and sensor electronics of all BPG400 gauges are identical.
Caution
Caution: data transmission errors
If the gauge is operated via RS485 and RS232C interface at the same
time, data transmission errors may occur.
The gauge must not be operated via RS485 and RS232C interface at
the same time.
Via this interface, the following and further data are exchanged between a bus
master (host) and the BPG400-SR (device) in the RS485 protocol.
• Pressure reading
• Pressure unit (Torr, mbar, Pa)
• Degas function
• Operation modes
• Status and error messages
• Thresholds of the switching functions
The BPG400-SR can be operated in two operation modes. While the "BPG" mode
(default mode) takes full advantage of all the gauges capabilities.
The "RIG" mode has a somewhat reduced scope of parameters (
→ 40).
The controlling host sends its commands to the individually addressed devices
connected to the bus. In replay the device returns the data requested via bus to the
host.
A maximum of 127 devices can be connected to a RS485 bus system.
• Data rates: 300, 1200, 2400, 4800, 9600, 19'200 1) , 28'800 Baud
• Byte: 8 data bits 1)
1 stop bit 1)
No parity 1)
1) Default settings
4.9 RS485 Interface
(BPG400-SR)
4.9.1 Description of the
Functions and Modes
Operation modes of the
BPG400-SR
4.9.2 Data Exchange
4.9.2.1 Operational Parameters