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Measurement Specialties Inc. NetScanner System (9016, 9021, & 9022) User’s Manual

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channel is affected by the command. The least-significant (rightmost) bit 0 corresponds to

Channel 1, and the most-significant (leftmost) bit 15 corresponds to Channel 16. Since neither

model has more than sixteen (16) channels, the position field will usually be 16-bits, represented

by four (4) ASCII-hex characters in the command. For example, only Channels 16 and 1 are

selected below in this 16-bit (4-character) position field:

Bit#

Chan#

Binary

Hex

The above position field, with all applicable bits set (i.e., FFFF for 16-channel module), specifies

all channels. However, a module-independent variation allows a missing position field to

designate all channels — but only when there are no other parameters following the position field

in the command. For such commands, the hex position field may be reduced to 3, 2, or 1

characters when no channel bits need be set (1) in the discarded high-order characters (nibbles).

3.1.2.4 Datum Fields

Any datum fields in a command generally contain data to be sent to the module, usually specified

by a position field bit map. In some commands (when data are received from a module instead) no

datum fields are required in the command itself but the position field bit map is still used to specify

the order that data are returned in the command’s response. In either case, the order bits are set (to

1) in the position field bit map (highest channel # to lowest channel#, left to right) is the order these

datum fields are received or sent.

Each datum field may be variable in length, whether part of the command itself or the command’s

response. In its most common format, a datum begins with a space character (‘ ’), and is followed

by an optional sign, decimal digits, and a decimal point, as needed (e.g., ‘ -vv.vvvvvv’). For other

formats it may be a hex digit string or pure binary number.

The channel data requested will always be returned in order of

highest requested channel to lowest requested channel.

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Pressure Systems 9022 Manual de usuario Pagina 37