Elseta IOMOD 4RTD Руководство пользователя - Страница 2
Просмотреть онлайн или скачать pdf Руководство пользователя для Измерительные приборы Elseta IOMOD 4RTD. Elseta IOMOD 4RTD 9 страниц. Modbus
Печатать страницу
Supported MODBUS functions
01 (0x01) Read Coil Status
Used to read fault flags. Fault is implemented as high logic level if any configured fault has occurred, zero otherwise.
Fault flags are cleared automatically if possible.
03 (0x03) Read Holding Registers
May be used to read holding registers containing temperature limits defined by user in degrees Celsius, fault mask
register.
Temperature limits are defined as 16-bit integer values. Values that are below or above the predefined limits are
ignored. These limits are described in Modbus register mapping table below. If upper limit value is lower than lower
limit value, these values are switched between them.
Fault mask registers contain information about fault bits that would be lifted in fault register if any particular fault for
particular RTD has occurred. Its values for every four RTDs are kept at holding register of addresses 11 to 14.
04 (0x04) Read Input Registers
May be used to read current temperature values and faults.
As temperature is kept as a 4-byte wide float value, two neighboring register are used to keep it. RTD values are kept
at registers 0 to 7, least significant word first. Values read can be easily converted using any converter capable of
converting floats based of IEEE-754 standard.
Fault register values are read as 16-bit input registers on addresses 16 to 19. Meanings of individual bits are explained
below, in subsection Fault registers.
06 (0x06) Preset Single Register
Used to set holding registers one by one described when explaining 03 Modbus function. That means that arbitrary
value may be written to set up different temperature limits and faults masks.
Modbus register table
Register (decimal)
00010-00013
00000-00007
00011-00014
00000-00007
00016-00019
00000-00007
00011-00014
Fault registers
Fault registers (Modbus addresses - 16-19) are read-only. They represent faults that occurred during operation of
device. To enable showing desired fault user should set appropriate bits in Fault mask register (Modbus addresses - 11-
14) or via USB interface, entering Advanced Settings Tab in RTD parameters menu. Fault registers and fault masked
registers are different for different temperature channels. Default values are shown in brackets below.
Fault register[15:14] shows flags that are lifted if temperature limits are exceeded. Bits[7:5,3:2] inform about faults
that were detected by RTD reading chip. These faults are usually lifted if unsuitable settings are set or RTD is faulty or
not connected.
Description
Read coil status (01)
Reading fault flags
Read holding register (03)
Get temperature limits (lower limit first)
Fault Mask registers for RTDs
Read input registers (04)
Temperatures from RTD sensors, LSW first
Fault registers for RTD sensors
Preset Single Register (06)
Set temperature limits (lower limit first)*
Set Fault Mask register for RTDs
Value range
0-1
-200-800
0-57836
0-65535
0-57836
-200-800
0-65535