SMAR TT301, Руководство по эксплуатации, техническому обслуживанию и инструкциям

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Programming Using Hand-Held Terminal
3.11
Current TRIM (4-20 mA output)
When the microprocessor generates a 0 percent signal, the Digital-to-Analogic converter and related
electronic circuits must emit a 4 mA output. If the signal is 100 percent, the output must be 20 mA.
Differences may occur between the SMAR standard current and the plant standard. In this case, the
current TRIM adjustment should be used.
The Configurator will adjust the output signal and then it will ask again if the current is correct or not.
Input Reading TRIM
There may be differences between the SMAR resistance standard and mV and the plant standards. In
this event, the user TRIM adjustment may be used. The TRIM available are: Zero trim, the Gain trim
and Factory trim.
- Zero Trim
– Calibrates the resistance or millivoltage lower value. The zero trim does not interfere with
the gain trim.
- Gain Trim
– Calibrates the resistance or milivoltage upper value.
- Factory Trim
– Recovers the Zero, Gain, and temperature sensor made in factory.
For zero or gain adjustment, a resistance or mV standard should be connected with a better than
0.02% accuracy.
If the transmitter is configured as either differential sensor, backup, average, maximum or minimum,
that is working with two sensors simultaneously, only the zero trim is available.
To perform zero trim, it should to short circuit the two sensors in the field and to enter with the value 0
(zero).
After perform the trim, remove the short circuit for the transmitter to read the sensors resistance without
the influence of the lines. The line maximum resistance should be less than 32
Ω for that zero trim
would be possible.
Temperature Sensor Trim
Althouth it is not necessary to perform the temperature trim of the terminal, it is possible a little
adjustment in the temperature measure through this menu.
Alarm
This function configures the three
TT301 alarms, with independent configuration for alarms 1 and 2
action and limit. All the alarms may be monitored and identified through this function. Alarm zero
indicates burnout and may be activated in this function.
Rec - Recognizes the alarm, while the ACK indication on the transmitter display disappears as the
pending alarms are identified.
Action - Configures the alarm operation mode: low, high or off.
Limit - Configures the level that the alarm is occurring.
Alarm Configuration
Low -
Is activated when the PV goes below the signal configured (decreasing).
High -
Is activated when the PV goes above the signal configured (increasing).
Off -
The alarm is disabled.
Online Multidrop Operation
The multidrop connection is made up of several transmitters connected in parallel in a single
communication line. The communication between the master system and the transmitters is digitally
done, with the transmitter analog output deactivated (TRM mode) or activated (PID mode).
The communication between the transmitters and the master system (PROG, DCS, data acquiring
system or PC) is performed through a Bell 202 modem using a HART protocol. Each transmitter is
identified by a single (1 to 15) address.