Measurement Specialties 9116 User Manual

Pressure Systems, Inc.                                                                                        Model 9116 User’s Manual 
 
 

 

Page 20 

 

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A typical UDP/IP command (contained in the data field following a UDP packet header) is also a 
variable length character string, but has a simpler format. Generally, it has a variable length 
command string (cccccc), followed by one optional datum ( dddd) field (preceded by one space 
character): 
 
 

“cccccc[ dddd]” 

 
Since there are only a few simple UDP/IP commands, all references to commands below should 
assume TCP/IP commands, unless otherwise indicated. 
 
3.1.2.2  

  Command Field 

 
All Model 9116 scanners recognize a set of predefined commands. Most are TCP/IP 
commands, having only a single alphabetic letter for a command field. These are recognized 
only when a formal socket connection is established with the host computer. A few are UDP/IP 
commands with a longer command field. These are recognized any time the module has power 
applied. All commands are functionally summarized in the following sections and detailed in 
reference Section 3.2. 
 
3.1.2.3  

  Position Field 

 
The Model 9116 Intelligent Pressure Scanner may contain up to sixteen (16) separate 
input/output channels. When commands affect certain channels scanned by the module,  the 
position field is used to identify those channels as bits in a bit map.  If a channel’s corresponding 
bit in the position field is set to a one (1), then that 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#  15 14 13 

12 11 10 9 8 7 6 5 4 3 2 1 0 

Chan# 

16 

15 14 

13 12 11 

10 9 8 7 6 5 4 3 2 1 

Binary  1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 

Hex 

8 0 0 1 

 
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).