ADS 507165, Инструкция по установке, эксплуатации и обслуживанию, Страница: 370 / 535

Analog and Digital I/O 9-7
Determine whether too much load exists on the analog signal
in the following way:
‰
Activate the monitor with the appropriate analog input
parameters.
‰ Request for the owner to simulate a full-scale event that
generates a signal to 20mA while connected to the XIO
unit. Simulate the full-scale event through utilities in the
transmitter that supply the signal or, when using a depth
sensor, by placing a target under the sensor that will
provide a maximum reading. Magmeters usually have a
utility to drive the output to full scale. However, each
device is different and, in some applications, there is no
way to simulate maximum output. When this occurs,
calculate the load by measuring the voltage that drives the
loop and then measuring the resistance added by each
device on the loop. The owner
’ s instrumentation
representative should conduct this load calculation because
it requires toggling power to different devices and
disconnecting/reconnecting the signal and, possibly, power
wiring.
‰ Using Q start
XML
, collect the data and verify that the analog
input values were correct during the simulated input time
interval.
Note: If the load is too great and/or the analog signal is
controlling the customer equipment, a loop isolator must
be installed before proceeding.