AG3000 INSTRUCTIONS
Seametrics • 253.872.0284
Page 18 seametrics.com
CONFIGURATION
Analog Output (4-20mA) Configuration.
(Not available
on battery only units.)
Since the meter’s analog output
is isolated and passive, loop power must be supplied
externally as shown on a previous page. (In addition, an
external resistor R
L
will be needed to convert the loop
current to voltage for voltage-only input devices.) The
meter’s loop transmitter minimum voltage drop is 6Vdc
(8Vdc with HART) which, with wiring resistance and loop
power supply voltage, will determine the maximum
resistance for R
L
. The flow rates corresponding to 4 and
20mA can be set by the user via the SET 4 and SET20 tabs
on the meter’s setup menus.
Note: As configured by the factory, any alarm state will
force 22.8mA on the loop. This can be changed to 3.2mA
- see Technical Bulletin, ‘iMAG4700/AG3000: Changing the
4-20mA Alarm’.
HART Configuration.
(Not available on battery only units.)
The HART protocol, rev.7.5, allows for a Polling address
between 0 and 63. The default value in the AG3000 is 0.
To change the Polling address, use AG3000 menu HPOLL to
set the Polling address.
To get to this menu, move to the EXIT tab and tap the left
button 4 times. This will bring up the SUBMENU page.
Navigate to the HPOLL tab. Use the left button to select
the Polling address.
To enter SUBMENU To select address
(See Changing Flow Meter Settings later in these
instructions for details in using the menu system.)
A minimum of 250 ohms of loop resistance must be present
in order for the HART modem to correctly and reliably
demodulate FSK voltage. With this in mind, the maximum
loop resistance* for the AG3000 HART interface cannot be
exceeded in order to assure correct operation.
The AG3000 HART interface is HART compatible. All the
commands have been implemented in accordance with the
HART Protocol Specification published by HART Foundation.
A HART Communicator can be used with the AG3000, even
in the absence of DD files, by taking advantage of the
Generic Online Menu capability of a Communicator. This
means that a generic menu is automatically available when
DD files are not present.
TAP
X 4
TAP
The following information from the AG3000 HART can
be displayed on the Communicator using the generic
menu:
PV
Flowrate in units selected for
AG3000
PV Loop
Current
Loop current in mA
PV LRV
Lower range value of PV in units
selected for AG3000
PV URV
Upper range of PV in units selected
for AG3000
*4-20 mA loop has maximum loop resistance of 650ohms
and requires a 24Vdc power supply.
Modbus
®
Serial Communication Configuration (factory
configured).
(Not available on battery only units.)
These
connections provide a half-duplex, isolated, RS485 serial
communications port using the Modbus messaging
protocol. The port is reconfigurable by
internal jumper
settings to full-duplex RS232 or 3.3V CMOS (See Seametrics
Modbus Interface Description manual for instructions).
The TXD connection is the transmitted data output from
the meter and RXD is the received data input to the meter.
See Seametric’s Modbus Interface Description, LT-103393
(available at www.seametrics.com) for supported Modbus
message protocol and electrical interface specifications.
Digital Output (High Frequency) Configuration.
(Not
available on battery only units.)
These outputs are electrically
similar to the Pulse Output described above except they are
capable of output frequencies up to 10kHz. The frequency
output scaling can be set by the user via the SETF tab on
the meter’s setup menus. Selections are: 500Hz and 1, 2, 5
and 10 KHz at maximum flow rate.
DOUT1 Pulses in forward direction
DOUT2 Pulses in reverse direction
K-Factors for High Speed Digital Output (High Frequency)
SETF (Hz)
Size
500
1K
2K
5K
10K
3”
41.55
83.10
166.2
415.51
831.02
4”
23.35
46.69
93.39
233.5
466.9
6”
10.38
20.75
41.51
103.8
207.5
8”
5.837
11.67
23.35
58.37
116.7
10”
3.736
7.471
14.94
37.36
74.71
12”
2.594
5.188
10.38
25.94
51.88
