Crystal 30 Series Digital Pressure Calibrator - Manual (Page 4)

Communication  2
30 Series Programming Instruction Manual
Communication
—
30 SERIES COMMUNICATION FORMAT
All Model 30 series products communicate and are calibrated through the micro USB interface. The port can be used to collect both displayed and internal
data, and all front panel keys can be actuated with the exception of the
(
contrast
)
and
(
power
)
keys.
The interface contains optical isolation, so that there is no direct electrical connection between the internal circuits and the external micro USB interface.
This eliminates the possibility of ground loops, which may affect the accuracy of measurements. It also presents an electrically dead connection (versus live,
exposed pins) when the unit is used in areas requiring intrinsic safety.
The Model 30 series products respond to one or two byte commands.
Two byte commands are used to distinguish between P1 and P2, for the Zero and Units keys.
Command Table
Command (ASCII) Operand Description Response
Z “1” or “2” ASCII Zero / Tare Same as pressing P1 or P2 ZERO key
C (none) Continuous Data Collection See Data String Format Table
S (none) STOP collecting data n/a
V (none) Firmware version Transmits Firmware version
P “1” or “2” ASCII P1 or P2 Units key Same as pressing P1 or P2 UNITS key
m (none) Press mA key Same as pressing mA key
Data Strings
Once an ASCII “ C” is sent, the unit will begin transmitting 31 byte, fixed length ASCII strings. The data string is identified by the prefix, has delimeters between
fields, and a line terminator that reflects battery condition. The last character of the 31-byte string is one of three battery status characters. If the battery is
good the character is “
>”, if the battery is low the character is “<”, and if the battery is dead (too low for accurate operation) the character is a question mark “?”.