B&B Electronics Zlinx 485 - Manual (Page 20)

Hardware
Manual Documentation Number: Zlinx485m-1808
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I/O Type
Modbus Memory
Address
DO 00001 to 00112
DI 10001 to 10112
AI 30001 to 30112
AO 40001 to 40112
Figure 20. I/O Memory Areas Table
Within these sections, addresses are reserved for all Zlinx 485 modules that may be used.
Module Memory Range
Base x0001 to x0016
Expansion 1 x0017 to x0032
Expansion 2 x0033 to x0048
Expansion 3 x0049 to x0064
Expansion 4 x0065 to x0080
Expansion 5 x0081 to x0096
Expansion 6 x0097 to x0112
Figure 21. Module I/O Addressing Table
The following examples show how the addressing works:
Example 1: To turn on the second digital output (DO2) on the Base Module, the Modbus
Base Module sends a message placing a logic 1 in memory location 00002.
Example 2: To cause expansion module 3 to output a specified voltage on AO1, the
Modbus Base Module sends a message to set the register at Modbus address 40049 to the
appropriate value.
A list of all Modbus address assignments for all Zlinx 485 points is shown in Appendix
D. Several important points about this list should be noted:
• Some addresses are listed but not implemented in current versions of Zlinx 485
hardware.
• Some addresses are reserved for internal Zlinx 485 use.
• Some addresses are reserved for future use.
• 40000 series addresses store Analog Output data AND Frequency Counter data when
Digital Inputs are configured for Frequency Counter operation. For each module, the
first eight memory locations are assigned to AO data and the next four locations are
assigned to Frequency Counter data.
• If a Modbus device communicating with Zlinx 485 tries to send to or receive from a
memory address not implemented by the hardware in use, the Zlinx 485 replies with
an exception response.
• Users cannot span across two memory maps, i.e. from 34 to 50.