Crystal XP2i-DP Digital Differential Pressure Gauge - Manual (Page 10)

Support  8
XP2i Programming Instruction Manual
Support
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trouBLeSHootInG tHe dIGItaL InterFace
The following section gives possible reasons for various error codes.
N,Ø . . . . . . . . .The “ Ø ” indicates there were no overrun or framing errors, so the command was properly received. However, the “ N ” means the XP2i could not
match it to any allowed command. This means the syntax must have been wrong. The command is rejected and nothing is done.
X Possible reasons:
•
Instruction sent without a comma between “ P ” and “ U ” of the “ ?P,U ” query.
•
More than 30 seconds passed to finish a command.
•
Line termination is incorrect; send carriage returns (CR) only, do not send line feeds (LF).
N,2 . . . . . . . . .XP2i buffer overflow, no action. In an overrun, bytes are lost, consequently the XP2i will not be able to match the command string. If it can’t find
a match, it returns “ N ”.
X Possible reason:
•
Not enough time allowed between commands. Check the communication parameters.
N,4 . . . . . . . . .Framing error: Bytes were lost. Therefore, the command could not be matched. A framing error can sometimes occur after power-on, after reset,
or when the batteries are changed; see the Programming tips on page 9 for suggestions on handling this.
X Possible reasons:
•
Noise on the line either created a false start bit or obscured the stop bit.
•
Multiple, but infrequent, framing errors are probably due to noise on the connection.
•
Frequent framing errors likely mean the XP2i or the PC is not operating at precisely 9600 Baud.
•
Occasionally, plugging the RS-232 connection into the XP2i will create a single framing error.
N,6 . . . . . . . . .Both buffer overrun ( N,2 ) and framing errors ( N,2 ) occurred during this command. The “ 6 ” represents the binary OR masking of the two bits
used to indicate a buffer overrun (bit 1) and a framing error (bit 2).
X Possible reason:
•
Look at “Possible reasons” for troubleshooting the N,2 and N,4 error codes, above.