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130 620 300 Rev.C 171116
Page 20 of 24
ProSMS 8
INSTALLATION MANUAL
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Diagnostic registers, MODBUS function Read 8
(continued)
The MODBUS function code 08 provides a series of tests to check communications between the client
(Master) and the Slave (ProSMS), or to check various internal error conditions within the ProSMS. This
functionality is most useful during installation to check that there are no communication problems across
the network before commissioning. It is recommended to read the Diagnostics registers periodically
(once per month) to confirm that the network is still performing optimally.
The function uses a two–byte sub-function code field in the query to define the type of test to be
performed. ProSMS echoes both the function code and sub-function code in a normal response.
The following diagnostic functions are supported by ProSMS:
Example Return query Data from device with address #5:
Example Return Slave Bus Message Count from device with address #5
(Slave had processed 200 messages):
In normal operation only “Return Bus Message Count” and “Return Slave Message Count”
will increment with each valid reading. The other registers (when there are no problems on the
bus) will read as 0.
It is not necessary to read the Diagnostic Registers on a regular basis since they are only
provided to assist the user in checking the MODBUS communications performance and in
identifying possible problems or troubleshooting.
The Diagnostic Registers are accessed one-by-one via sub-functions, per the MODBUS
specifications.
Slave Address
Function
Sub-Function
Data
CRC
Master Query (HEX)
05
08
0000
1234
ECF8
Slave Response (HEX)
05
08
0000
1234
ECF8
Slave Address
Function
Sub-Function
Data
CRC
Master Query (HEX)
05
08
000B
0000
904D
Slave Response (HEX)
05
08
000B
00C8
91DB
CAUTION
VOLTAGE
DANGER
WARNING
NOTICE
CAUTION
VOLTAGE
DANGER
WARNING
NOTICE
CAUTION
VOLTAGE
DANGER
WARNING
NOTICE
7.1
Device operation
When there is sufficient solar panel illumination to produce at least 90V system voltage, ProSMS will
self-power and begin to operate. Start of operation is signaled via a short blink of the Green, Yellow, and
Red LEDs simultaneously. Immediately after powering up, measurements begin to be taken, averages
form and energy yield is accumulated in various registers used for such logs. Normal device operation
is signaled via a steady short blinks of the Green Power LED at 1s intervals (system heartbeat). During
MODBUS communications, the Yellow communication LED will blink. Illumination of the Red LED
signifies an Error condition of the Power Supply or the central CPU.
7.2
Energy measurement per string
To identify those strings which may be operating at less than optimal efficiency ProSMS includes an
internal functions whereby the energy consumption of each string is measured and recorded. This
function can be useful to the system operator when trying to identify those strings not performing
correctly (due to dirt, poor connections, of general failure). In its simplest form, the energy of each string
can be logged on external software to identify trends and anomalies of certain strings.
The onboard energy monitor also provides a means of comparing the daily energy production recorded
by the unit itself, to that recorded at the output of the inverter. This can be used to provide insight as to
the losses on connections between Combiner boxes and Inverter to monitor inverter's and transformer's
efficiency and any imminent failure. The onboard energy registers can record consumption to 21.474
GWh for each string - enough for approximately 25 year of PV plant operations.
Summary of Contents for ProSMS 8
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