Dynisco TX180, Инструкция по установке и эксплуатации

Страница: 22 / 52

22
4.9 T
RIM
4.0
M
A
This allows trimming of the 4.00mA output current.
NOTE: This function is only for the purpose of adjusting the 4.00mA limit of the transmitter loop
current to be exactly 4.00mA according to the plant’s local standard. This is NOT for the
purpose of ranging the transmitter!
If trimming the 4.00mA limit is still desired then press
ENTER
. The transmitter will now output a
milliamp current equal to its internally set 4mA. This 4 mA value should be read on an external
meter and compared to a local standard. It is advisable to use a very good voltmeter to make these
comparisons. It is very possible that the transmitter will be more accurate than a great many
voltmeters. In this case, trimming will make the transmitter less accurate rather than more accurate!
Once trimming the 4.00mA value has been selected, the display will alternate as follows:
By pressing the
NEXT
key the display then alternates as
When it is decided whether to raise or lower the output current, then press
ENTER
and the display
changes to one of the following depending on whether the raise or lower function has been
selected.
Now every time the
NEXT
key is pressed, the display blinks, and the 4.0mA output limit decreases
(-), or increases (+). The decrease or increase is in approximately 3.5 micro ampere increments.
NOTE: The 4.00mA limit is factory calibrated to a precision standard. Using the Output Trim
function voids the NIST traceability of calibration. Do not arbitrarily trim the output unless a
qualified and accurate local standard is available to measure the adjusted 4.00mA output!
Also note that the 4.0mA limit should not be trimmed by more than about 50A, or
transmitter operation may be impaired.
Once the desired trim is reached, pressing
ENTER
will return to one of the corresponding
TRIM
4mA
screen. At this point one may still go back and do further trimming of the 4.0mA limit by
TRIM 4 MA?
RAISE MA OUT?
LOWER MA OUT?
NEXT = + NEXT = -