Fema Electronica K Series, Руководство пользователя, Страница: 14 / 32

FEMA ELECTRÓNICA . Series K . K40-232
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The ‘watchdog’ function activates an error state in case of loss of
communication with the ‘master’. To configure the ‘watchdog’ indi -
cate the maximum time accepted to wait between two frames re -
ceived. If this time exceeds, the ‘watchdog error’ activates. Receiving
a correct frame resets the ‘watchdog’ timer.
Frames that can reset the ‘watchdog’ timer are those addressed to
the ‘slave’ instrument. These frames must conform to the indicated
ASCII protocol and have a correct CRC.
If the function or register or coil indicated in the frame is not correct,
the ‘slave’ instrument will still reset the ‘watchdog’ timer. It will also
reply with the corresponding error message.
The internal alarms of the instrument can be associated to the
‘watchdog’. In case of ‘watchdog’ activation, the associated alarm
will also activate.
Display can also be configured to show an error message in case of
‘watchdog’ error. It can be configured for flashing, dash (‘------’) or to
show message ‘Err.W’.
See sections
1.28.4
and
1.28.5
for information on alarm configura -
tion and section
1.28.3
for information on ‘watchdog’ configuration.
‘Bus activity’ function is a detector of electrical activity on the bus.
The function is to help when connecting the instrument to the bus
for the first time. It provides information on wether there is electrical
activity on the bus or not.
The ‘Bus activity’ function is visible in the form of a counter increas
-
ing its value on the display. It indicates that the UART is detecting
information bytes on the bus. This detection means that there are
data on the bus, and that it conforms to the configured speed and
data format.
‘Bus activity’ function is accessible at key UP (
5
), when enabled as
indicated in section
1.28.6.
1.23 Numerical registers : restrictions
Registers which must contain a numerical value, are controlled to as -
sure that the value received from the frame is a true numerical value.
If controls are successful, the value is saved into the register. Other -
wise, an error is generated. Registers which must contain numerical
values are the following :
• ‘Display’ register
• ‘Setpoint 1’, ‘Setpoint 2’ and ‘Setpoint 3’ registers
When writing data into these registers, the instrument converts the
ASCII characters received on the ‘DATA’ section of the frame, to a
numerical value. The following controls are applied, in the order in -
dicated below :
• Section ‘DATA’ can not be empty of characters. It generates an
error 6 ‘Empty Data’.
• First character must be ‘+’, ‘-’, ‘.’, ‘,’ or a number from ‘0’ to ‘9’. It
generates error 10 ‘First char error’.
• Section ‘DATA’ must contain maximum one decimal point. It
generates error 11 ‘Format error’.
• Section ‘DATA’ can contain only characters from ‘0’ to ‘9’ or dec
-
imal point (‘,’ o ‘.’). First character has already been controled and
is not controlled again. If other character is found, it generates
error 11 ‘Format error’.
• If section ‘DATA’ does not contain decimal point, its maximum
length is 7 characters. If section ‘DATA’ contains decimal point, its
maximum length is 8 characters. Larger data generates error 12
‘Out of range’.
• Conversion from ASCII characters to a number. Decimal point is
separated from the number, which is treated as an integer.
Examples : possible conversions are as follows:
‘1234’ is read on display as 1234
‘-1234’ is read on display as -1234
‘-12.34’ is read on display as -12.34
‘+.995’ is read on display as 0.995
‘+0.995’ is read on display as 0.995
‘0.995’ is read on display as 0.995
‘.995’ is read on display as 0.995
‘+0027’ is read on display as 27
‘+27’ is read on display as 27
‘27’ is read on display as 27
• The numerical integer is sent to display. If the number is higher
than the maximum number that can be represented by the dis -
play, it generates an error 12 ‘Out of range’.
Example : ‘-67.89’ is not representable on display, because
minimum display is -1999. Instrument will generate an
‘Out of range’ error. ‘Display’ register is not updated. It
generates an answer frame 12 ‘Out of range’ if the writing
was requested with a ‘WRA’ frame.
Note : character ‘.’ and ‘,’ are equivalent and both are associated
to the decimal point.
1.24 Addresses and ‘broadcast’
Addresses available to assign to the intruments are from 1 to 31. Ad -
dress 128 is a ‘broadcast’ address.
Instruments will accept and process frames when destination ad
-
dress of the frame matches its own address.
All frames addressed to destination address 128 will be accepted by
all instruments, independent of its own address. Instruments will not
generate answer frames when destination address is 128.
• a ‘ping’ (‘ PING ’) frame to destination address 128 will not gen -
erate answer
• a ‘write with aknowldgement’ (‘ WRA ’) frame to destination ad -
dress 128 will not generate answer
• a ‘read’ (‘ READ ’) frame to destination address 128 will not gen -
erate answer
• a frame to destination address 128 which contains an error (a
CRC error for example) will not generate answer
1.25 ‘Watchdog’ function
1.26 ‘Bus activity’ function