19
NT935 ETH
NOTES FOR REMOTE PROGRAMMING
The writeable registers are shown in the MODBUS MAPPING TABLE as W or RW (
write or read/write)
max number of
registers 72, see table page. 20.
Channels 1÷3 are not disabled; in case of incorrect setting, they are always forced as enabled channels.
If the channel 4 is not enabled and/or the information is not provided for, the following answers are given:
1.
Measured temperatures
= 0000 (0°C)
2.
Temperature AL./TRIP
= Value written in E2PROM
3.
Channel state
= 0000
4.
Channel setting
= %00000000; %xxxxxxx0 (x=n.d.)
If writing information is sent towards a READ-only register, the data will be binned without affecting the message received.
Also in remote programming via ModBus you must take into consideration that the Alarm thresholds must be lower than the
Trip thresholds and that the Fan-on thresholds must be higher than the Fan-off thresholds.
If you try to set these thresholds wrongly, the NT935 ETH monitoring unit won’t proceed with programming and data
storage; therefore in the following readings you will read the data relevant to the previous programming.
After sending a writing request,
the monitoring unit will require approximately 1’’ to store the data in eeprom; during the
storage phase, the ModBus module will not be able to process other requests.
If the programming request is successful, the control unit automatically resets and loads the newly set values.
The information "RELAY STATUS" indicates the state of excitation of the coils of the relays, so it will be subject to the
commands of "FAIL SAFE".
At the end of the Write command, data compatibility is checked:
1.
in case of incompatibility, the answer is an "exception" and the data packet is refused in full. The code of the
first wrong datum can be requested reading the "Datum error received" register. (NB: this code is lost during
RESET, switching on or data writing in E2PROM);
2.
if the data are correct, they are transferred into the non-volatile memory (E2PROM), historical data are
cancelled (Tmax=0°C) and, then, a system RESET is forced.
3.
If the WRITE command entails only writing "COMMANDS", it will be performed autonomously and without a
RESET, that is without affecting the control unit data.
ERROR CODES (exception codes)
In case of a wrong request, ModBus will answer with modified codes and codified errors according to the following:
1:
- Unsupported function code
2:
- Wrong data address
3:
- Wrong data (for instance length)
The memory area containing the HFN datum must undergo no forcing.
In the case in which all the fans are turned off (F1, F2) the test of the relay will not take place.
UNACCEPTABLE DATA
Some programming is unacceptable since the NT935 ETH does not provide for it; these data are discarded with no
EXCEPTION CODE.
CH 1-2-3:
channels cannot be disabled
CH 1-2-3:
FAN_2 cannot be enabled
CH 4:
FAN_1 cannot be enabled
CH 4:
FAN_INT cannot be enabled
CH 4:
FAN_2 cannot be enabled if CH 4=no
GENERAL UNIT NOTE
The models of the unit can be equipped with different options ; to avoid disruption of production , their existence is defined
by Fw indicated power , with messages dedicated on display LEDs .
This information can be accessed by reading the Modbus register 6 ( option ) with the following meaning :
LOW Byte
Bit_1 = Ethernet
HIGH Byte
Bit_0/1 = 00 - Range 0°C ÷ +240°C
Bit_0/1 = 10 - Range -40°C ÷ +200°C
In case of Ethernet option Modbus and 4.20mA mode shall not be active on the display. They will be readable from the log.
Note: in case the values programmed from ModBus are out of range, it will generate a "exception" error response
to date.
