PCE-HT 422
User’s Manua l
26
5.6.6.1. Description of implemented functions
PCE-HT 422
monitors have the following MODBUS functions:
●
03 (03h) – readout of registers group.
●
04 (04h) – readout of input registers group.
●
17 (11 h) - identification of slave device.
5.6.6.2. Map of registers
In
PCE-HT 422
monitor the data is placed in 16- bit registers. Process variables
and parameters of the monitor are located in the address space of registers in a
manner dependent on the type of the variable. Bits in 16-bit registers are numbered
from the youngest to the oldest (b0 ... b15). 32-Bit registers (4 Bytes) contain floating
point numbers in IEEE-754 standard. Order of bytes: B3 B2 B1 B0 – the oldest byte is
sent first. 16-Bit registers representing 32-bit values in two subsequent registers are
doubled in another address area with the following bytes order: B1 B0 B3 B2 (Tab. 6).
The map of the
PCE-HT 422
monitor registers is presented below.
Caution:
All given addresses are physical addresses. In some computer programs, logical
addressing is applied, then addresses must be increased by 1.
Table 6
Address range
Value type
Description
6000-6198
float (32 bits)
Value is placed in two successive 16-bit registers. Registers
contain the same data as 32-bit registers of 7500 range.
Registers are read-only. Bytes order (B1,B0,B3,B2)
7000 -7198
float (32 bits)
Value is placed in two successive 16-bit registers. Registers
contain the same data as 32-bit registers of 7500 range.
Registers are read-only. Bytes order (B3,B2,B1,B0)
7500-7599
float (32 bits)
Value is placed in 32-bit register. Registers are read-only.
