1.1 General
The transmitter board is fitted inside the
enclosure of the flow meter, Option W2 provides a 4-20mA dc output in
addition to a local mechanical analog readout. Option W3 operates
identically, but omits the local mechanical indicator.
The transmitter measures differential pressure
directly with a solid state strain gage. The differential pressure measured
is independent of the mechanical measurement provided by the local
mechanical indicator. The output of the transmitter is linear with
differential pressure. The output must be linearized in the
receiving device to provide a flow measurement. The transmitter is powered
by an external 24 volt dc power supply provided by the user. A rated
capacity of 25mA minimum is required.
1.2 Installation
For NEMA-4, 4X or IP66
installation (Option "D"). Use CSA / UL approved watertight conduit
or cable gland (not included).
For EMC (Electromagnetic Compatibility)
installation (Option "EM"). Use AWG 18, shielded cable
with drain wire (CSA, UL, CE approved).
Important: Terminate shield inside outer housing but outside
inner shield housing. See figure 3 for details.
For IS installation (Option "IS").
Option IS includes Option D and a locking screw on the lens bezel. This
screw must be loosened 1/2 turn to obtain access to the dial and pointer.
See IS installation drawing #6440 for wiring and barrier installation.
Important: Atex installation must comply
with EN 60079-14
CSA /
NRTL: Ex ia IIC T3
CENELEC / LCIE: EEx ia IIC 1G
Class I, Division I, Groups A, B, C, D
T3, Ta = 0 to 50°C
Class II, Division I, Groups E, F, G
Atex Directive 94/9/EC, EN 13980:2002
Startup: Pressurize the pipeline and
check the zero. Adjust the zero pot if necessary.
2.1 Test Equipment
Fluke 9600A digital multimeter or equivalent. All flow meter are factory calibrated. Connect multimeter
in series with current loop.
2.2 Procedure
With pipeline pressurized, adjust zero pot until current reads 4.00mA ±
0.02mA at no flow. Establish a known flow rate
though the flow meter as close to 95% of full scale as practical. Set span, span is set using
the following formula: I = 16 Q² + 4.00; where I = current output in mA, Q =
decimal % of full scale. Click
here for 4-20mA to flow or flow to 4-20mA calculator. Click
here for calibration video clip.
| % FS |
Current Output |
% FS |
Current Output |
| 20 |
4.64 |
70 |
11.84 |
| 30 |
5.44 |
80 |
14.24 |
| 40 |
6.56 |
90 |
16.96 |
| 50 |
8.00 |
95 |
18.44 |
| 60 |
9.76 |
100 |
20.00 |
