Rosemount 3491, Справочное руководство, Страница: 83 / 152

Reference Manual
00809-0100-4841, Rev. AA
May 2007
4-51
Rosemount 3490 Series
Totaliser Relay
Menu:
MAIN MENU / SETUP / [CONTROL UNIT /] OUTPUT / TOTALISER
Each time the internal totaliser count (D828) increments, a relay may be
allocated to provide a pulse. The duration of the pulse may set via P534.
P534 Totaliser Pulse Width (Factory default is 100)
The duration controls both the 'On' time and the 'Off' time - i.e. the pulse width
- and may be set to a value between 10ms and 2.5 seconds in steps of 10ms.
If the totaliser count is running faster than the relay can produce pulses, an
internal accumulator stores the excess pulses; they will be produced by the
Totaliser relay once the totaliser count rate reduces.
Sampler Relay
Sampler relays output pulses at a slower rate than a Totaliser relay. The
Sampler relay can be used as a coarse totaliser or as a trigger to an external
event.
Menu:
MAIN MENU / SETUP / [CONTROL UNIT /] OUTPUT / TOTALISER
P535 Sampler Factor (Factory default is 0)
This is for defining the frequency of the Sampler pulse. For example, a value
of 100 means that the Sampler relay outputs a single pulse for every 100th
increment to the Totaliser Count (D828/D829). The pulse width is the same as
selected for the Totaliser relay (P534). For information on setting up the
totaliser, see page 4-63 onwards.
Fault Relay
A Fault relay is de-energised when a particular fault condition exists.
Parameter D831 is a fault report and shows a list of active faults. Table 4-15
on page 4-62 has a summary of reporting methods for faults.
Menu: MAIN MENU / SETUP / [CONTROL UNIT /] OUTPUT / FAULT
P560 System Fault (Factory default is "Both")
The Fault relay is de-energised when there is a system fault and the option
selected is "Both" or "Relay".
P561 CU Temp Fault (Factory default setting is "None")
The Fault relay is de-energised if the temperature of the CPU rises above
65
° C, and the option selected is "Both" or "Relay". Parameter D844 shows
the operating temperature of the 3490 Series Control Unit.
P562 Xmtr Fault (Factory default setting is "None")
The Fault relay is de-energised when the transmitter signals a fault and the
option selected is "Both" or "Relay".
Faults can be indicated on the Current Output if you select the "Current" or
"Both" options. See also the Alarm Action parameter (P402) description in
Section “Current Output“ on page 4-39.