Pressure Systems 98RK, 9816 user manual Interpreting Offset Values Re-zero Calibration Adjustment

Pressure Systems, Inc. 98RK-1 & 9816 User’s Manual©

The error response consists of the letter ‘N’ (for NAK, or negative acknowledge), followed by a 2-digit hexadecimal error code. The following table lists the error codes that can be returned from a 9816 NetScanner™ System module:

CODE

MEANING

00 (Unused)

01Undefined Command Received

02Unused (by TCP/IP)

03Input Buffer Overrun

04Invalid ASCII Character Received

05Data Field Error

06Unused (by TCP/IP)

07Specified Limits Invalid

08NetScanner error: invalid parameter

09Insufficient source air to shift calibration valve

0A Calibration valve not in requested position

The Acknowledge response is returned from a module when a command is received that requires no data to be returned, and no error is detected. It indicates successful parsing and execution of the last received command. It consists of the letter ‘A’ (for ACK, or acknowledge).

The Acknowledge with Data response is returned when a module receives a command requesting data. Model 9816 modules will typically return only the requested data values, each preceded by a space character (except for format 7). No 'A' (acknowledge) letter begins this data response. Data are returned for the highest requested channel number first. Data for lower requested channels follow in reverse order (e.g., P&S, then 16-1).

3.1.4.1Interpreting Offset Values (Re-zero Calibration Adjustment)

When a Model 9816 module is instructed to execute the command Calculate and Set Offsets ('h'), a datum corresponding to the calculated offset correction term (or coefficient) is returned for each affected channel. Each such coefficient value is stored internally, and will be subtracted in all subsequently calculated data conversions, to correct for zero drift effects. The command only returns them in the response (in current engineering units (EU) of pressure near 0.0) to allow the user to make reasonableness checks on them. The Read Internal Coefficients ('u') command will return them on demand.

3.1.4.2Interpreting Gain Values (Span Calibration Adjustment)

When a Model 9816 module is instructed to execute the command Calculate and Set Gains ('Z'), a datum corresponding to the calculated gain correction term (or coefficient) is returned for each affected channel. Like the offset coefficient, each gain coefficient is stored internally, and will be used in all subsequently calculated data conversions, to correct for gain change effects. The command returns them in the response (as a unitless factor near 1.0) to allow the

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