Fluke NetDAQ 2640A, Service Manual

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Theory of Operation
A1 Main to A3 A/D Converter Communications
2
2-47
Return Boot Firmware Version 2-83.
This Command Packet Format requests version number of the inguard boot firmware
and always returns a single response packet.
Response Packet Format The response consists of five ASCII characters (plus the
checksum byte), in the form Bxxyy, where B indicates boot software, xx are the two
digits of the major version number, and yy are the two digits of the minor version
number (there is an implicit decimal point between the two). Note that constraining the
bytes to be ASCII characters causes the most significant bit of each character to be a 0,
making the response packet always distinguishable from a NAK.
Set Global Configuration 2-84.
The Command Packet tells the A/D the following:
•
Measurement Rate, fast, medium, or slow
•
Power Line Frequency, 50 Hz or 60 Hz
•
Scheduled Housekeeping Measurements, Enable or Disable
Action Performed Sets global configuration parameters (instrument measurement rate,
AC power line frequency, and enable or disable housekeeping measurements). The
default state for the inguard is to measure on the fast rate, assuming 60 Hz, and with
scheduled housekeeping measurements enabled. The meaning of “scheduled
housekeeping measurements” depends on the current measurement rate.
Response Packets Returned Always returns a single response packet.
Response Packet Format Returns either an ACK packet or a NAK if the command
arguments are not recognized.
Set Channel Configuration 2-85.
The Command Packet tells the A/D the following:
Measurement Function VDC, VAC, 2-Wire Ohms, 4-Wire Ohms, Frequency,
Thermocouple, OFF.
Range 90 mV or 300 ohm, 300 mV or 3 k
Ω
, 3V or 30 kohm, 30V or 300 k
Ω
, 50V
(2645A), 150/300V (2640A), or 3 M
Ω
, 750 mV (reference junction calibration).
The range field is ignored for frequency and thermocouple channels.
Channel Number 0 to 19 (though user sees channel 1 to 20)
Enable Autorange if bit set (ignored for frequency and thermocouple).
Enable Open Thermocouple Detect if bit set.
Checksum Action Performed is configuration of a single channel to the parameters
given. The Response Packets Returned always returns a single response packet. The
Response Packet Format returns an ACK response packet if the channel was successfully
configured; otherwise, it returns a NAK.