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MX 43
Gebruikershandboek
Transfer Table
Two types of information can be retrieved via the RS485 output:
■
Information about sensor configuration;
■
Real-time sensor information (measurements, alarms, etc.).
1. Access to configuration information
It is possible to access the installation configuration (for example, to access
the alarm thresholds or the names of the sensors).
This configuration information is listed in the transfer table from address 0 to
address 1999.
The address of the detectors is determined as follows:
■
For a digital sensor:
Sensor address = (line number – 1) x 32 + slave number
■
For an analog sensor:
Sensor address = 256 + line number
Once the sensor address is known, the desired request can be executed by
following the transfer table below. For example, to find the instantaneous
alarm threshold number 1 for a sensor, read register number 52.
All of the information at addresses 1 to 52 will be accessed. The 52
corresponds to the expected value.
Example
Access instantaneous alarm 1 for the sensor located on line 8 at address 2 of
unit 2.
A. Determination of the sensor address: (8 – 1) x 32 + 2 = 226.
B. Structure of the Modbus request:
-
Slave number for the unit (defined by COM 43)
-
Operating type (03 = read)
-
Sensor address
-
Number of words to read (see Excel document)
-
CRC
Thread: 0x02 0x03 0x00 0xE2 0x00 0x3A 0x65 0xDC
2. Access to real-time information
Measurement and alarm information from the detectors is listed in the transfer
table from address 2000 to 65535. The sensor measurements are available at
addresses 2001 to 2264, the sensor statuses are available at addresses 2301
to 2564 (alarm 1, alarm 2, etc.).
nd
word
02 = 0x02
03 = 0x03
226 = 0x00E2
52 = 0x3A
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