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mx7b_im rev E Page
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9.
RS-485 and USB Communications
9.1
Description
9.1.1
This gauge communicates with the host computer through an RS-485 or USB interface. Each
communication correspondence consists of a command line sent by the host computer and a
response from the gauge.
9.1.2
To communicate with the MX7B via RS-485, the user must have an RS-485 capable device to send
commands to the MX7B. Each command must be preceded by a *, the address, and will be an S,
R, W, RC, or WC.
9.1.3
To communicate with the MX7B via USB, the user must have a USB capable device to send
commands to the MX7B. Each command must be preceded by a * and will be an S, R, W, RC, or
WC. Because USB is a serial bus, the unit address is omitted from commands. See the
Communications Specifications heading for information on what settings are necessary to
properly communicate with the MX7B.
9.2
Changing Communications Settings
9.2.1
The communication parameters, (baud rate, address, etc.), are changed through the local menu.
Please see Section 6 in this manual entitled Explanation of Menu Items and Navigation for more
information on navigating and editing within the menu. Below are provided some specifics on
the RS-485 and USB Communications of the MX7B.
9.3
Communications Specifications
9.3.1
RS-485 Communications Specifications
Interface
RS-485 compatible
Data Transfer Method
Synchronous/half duplicate method
Baud Rate
9600/19200/38400/57600/115200
Data Format
1 start bit, 8 data bits, 0 parity bits, 1 stop bit
Error Detection
Parity bit
Parity Bit
None
Stop Bit
1
Transfer Distance
Max 100 meters
9.3.2
USB Communications Specifications
Interface
USB type B receptacle on module
Type
USB 2.0
Class
USB communications device class (USB CDC)
Baud Rate
115200
Transfer Distance
Max 5 meters
