GHM Delta OHM PMBsense-A, Руководство по эксплуатации

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PMsense
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V1.0
4 CONFIGURATION AND MEASUREMENT
The configuration of the instrument and the reading of the measurements can be done
via the RS485 serial output, both with the proprietary protocol and with the MODBUS-
RTU protocol.
In the first 10 seconds after the instrument power on, it is always active the proprie-
tary protocol. After 10 seconds from power on, the operating protocol is activated,
which by default is the MODBUS-RTU protocol.
It is possible to keep the proprietary protocol active even after 10 seconds from power on
by sending, before the 10 seconds expire, the command
@ of the proprietary protocol.
The proprietary protocol can be set as operating protocol by means of the DP0 command.
The commands of the proprietary protocol and the registers of the MODBUS-RTU pro-
tocol are described in detail in the following chapters.
Particulate Matter measurement modes:
The transmitter can perform the PM measurement in continuous mode, or, in order to
extend the sensor lifetime, at cyclic intervals.
By default, the transmitter is configured to measure at cyclic intervals with an interval
of 5 minutes. The measurement mode and the interval can be configured respectively
by using the CPLS and CPLP commands of the proprietary protocol or the holding reg-
isters with address 15 and 16 of the MODBUS-RTU protocol.
In the measurement mode at cyclic intervals, the PM sensor is activated periodically
for about a minute, at the end of which the measurement is made available and "fro-
zen" (the sensor is deactivated) until the set cyclic measurement interval expires. The
measurement provided is a value averaged during the minute of sensor activation.
In continuous measurement mode the sensor is always active, and the measurement
provided is an averaged value chosen from the following possibilities:
•
average over a 10 seconds interval, updated every second;
•
average over a 60 seconds interval, updated every 10 seconds (default);
•
average over a 15 min interval, updated every minute.
The type of average can be configured by using the CPS command of the proprietary
protocol or the holding registers with address 19 of the MODBUS-RTU protocol.
Status of the transmitter:
There are two LEDs on the internal electronic board of the transmitter: the green LED
indicates the presence of the external power supply (blinks once per second), the red
LED indicates the presence of any measurement errors (normally off, it blinks twice
per second if at least one of the measured parameters is in error).