Sensaphone WEB600 Users manual - Manual (Page 41)

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appendix C: Modbus® specifications
Contacts BasE + (oFFsET * ((proFilE_nUMBEr * 6) +
ConTaCT_nUMBEr)) The contact number is as follows:
Contact 1 = 0
Contact 2 = 1
Contact 3 = 2
Contact 4 = 3
network BasE
system BasE
quick access table
The following is a quick access table to retrieve the word-access, read-only current input values
as human-readable ASCII strings. Use the Modbus® command “4” to access the data.
Address Description
3x1552 power
3x1594 Battery
3x1636 Zone 1
3x1678 Zone 2
3x1720 Zone 3
3x1762 Zone 4
3x1804 Zone 5
3x1846 Zone 6
3x2854 output
ModbUs® data ForMats
bit-representation
The Modbus® interface supports a programmable bit ordering. Both the byte- and word-orders may be individually
programmed to either little- or big-endian formats. The default is big-endian byte-order and little-endian word-
order. This only applies to numeric values. Array, string and bit types are always given in the same format.
bit
Bit values are boolean values where 1 is “true” and 0 is “false”.
uint8, sint16, uint32, sint32
These are integer data formats. The “u” stands for “unsigned”, the “s” stands for “signed”. The number
indicates the number of bits used to represent the data: 8, 16, or 32 corresponding to 1, 2, or 4 bytes
respectively. 1 and 2 byte integers are stored in one Modbus® register while 4-byte integers are stored
in two consecutive Modbus® registers. The byte- and word-orders are programmable.
The integer types may be either fixed-point format or the standard straight integer format. Fixed-
point integer formats are offset by “100”, so divide the straight binary value by “100” to get the real
value. This provides 2 decimal places of precision for a maximum range of ±80000.00.
Float
This is a standard IEEE 754 32-bit floating-point number. All floating-point numbers will be in this format
and span 2 consecutive Modbus® registers according to the programmed byte- and word-orders.
string and array
Strings and arrays are strings of 0 or more characters/bytes. They are always returned first-byte first and last-byte
last. Strings are null-terminated with a binary 0 only if they are smaller than their maximum size. For example,
a “name” string may be up to 32-characters long. A value of “John Doe” would be terminated by a “0” because
it is less than 32-characters long, but not a name that is 32-characters long. Arrays are never terminated.