Vertu Series VPM3000 Process Meters & Temperature Transmitters
Instruction Manual
30
Serial Communications (
serl
)
The meter is equipped with serial communications
capability as a standard feature using DisplayWizard
software or using the Modbus RTU protocol. To
communicate with a computer or other data terminal
equipment, an RS-232, RS-485, or USB adapter
option is required; see
When using more than one meter in an RS-485 multi-
drop mode, each meter must be provided with its own
unique address. The address may be programmed
from 00 to 99 for PDC protocol and from 1 to 247 for
Modbus protocol. The transmit delay may be set
between 0 and 199 ms (see Serial Communication
Adapter manual for more details).
The Vertu can also be connected directly to another
Vertu meter through a cable assembly (
APMA7420
).
This allows the user to copy all the settings from one
meter to another, using the
Copy
function.
Protocol Selection Menu (
Prot
)
The Protocol selection menu is used to select either
the PDC (
Factory use only
) or the Modbus protocol.
PDC protocol should be selected to run
DisplayWizard software.
Select Menu (
SElc
)
The
Select
menu is used to select linear or square
root function, display intensity, and low-flow cutoff.
Selection for relay or analog output is a factory setting
depending on the option installed.
•
Output options are installed and set up at the
factory.
•
Changing the output selection will cause
erroneous operation.
Note:
Depending on meter model, the
Select
menu will
display either
out
or
Aout
. In either case, the output selection
menu is for factory use only. Do not attempt to change
output selection.
Linear or Square Root Function
(
linr
or
Sqrt
)
Meters are set up at the factory for linear function.
The linear function provides a display that is linear
with respect to the input signal.
The square root function is used to linearize the signal
from a differential pressure transmitter and display
flow rate in engineering units.
Low-Flow Cutoff (
cutF
)
The low-flow cutoff feature allows the meter to be
programmed so that the often-unsteady output from
a differential pressure transmitter, at low flow rates,
always displays zero on the meter.
The cutoff value may be programmed from 0 to 9999.
Below the cutoff value, the meter will display zero.
Programming the cutoff value to zero disables the
cutoff.
