Dwyer 616W - Manual (Page 3)

Calibration Check - Each Series 616W Transmitter is factory calibrated
to the range given in the model chart. To check calibration and adjust if
necessary, the following procedure should be used. For purposes of
clarification in these instructions, range is defined as that pressure which,
applied to the transmitter, produces 20 milliamps of current in the loop.
Zero pressure is always assumed to be 4 milliamps.
1. With the transmitter connected to the companion receiver, insert an
accurate milliameter in series with the current loop. Full scale range
should be approximately 30 mA.
2. Connect a controllable pressure source to one leg of a tee with the
other two legs connected to the high pressure port of the transmitter and
the third leg to an accurate test gage or manometer, in an appropriate
range. The low pressure port should be vented to atmosphere.
Calibration must be performed with the unit in the same position in which
it will be mounted.
3. Apply electrical power to the unit and allow it to stabilize for 10
minutes.
4. With no pressure applied to the transmitter, adjust ZERO control so
that loop current is 4 mA. See Fig. K.
5. Apply full range pressure and adjust loop current to 20 mA using SPAN
control.
6. Relieve pressure and allow transmitter to stabilize for 2 minutes.
7. Zero and span controls are slightly interactive, so repeat steps 4
through 6 until zero and full range pressures consistently produce
currents of 4 and 20 mA respectively.
8. Remove the milliameter from the current loop and proceed with final
installation of the transmitter and receiver.
MULTIPLE RECEIVER INSTALLATION
An advantage of the standard 4-20 mA DC output signal produced by the
Series 616W Transmitter is that any number of receivers can be
connected in series in the current loop. Thus, an A-701 Digital Readout,
an analog panel meter, a chart recorder, process controlling equipment
or any combination of these devices can be operated simultaneously.
The only requirement is that each component be equipped for a standard
4-20 mA input and the proper polarity of the input connections be
observed when inserting the device in the current loop. If any of the units
display a negative or downscale reading, the signal input leads are
reversed.
MAINTENANCE
Upon final installation of the Series 616W Differential Pressure
Transmitter, no routine maintenance is required. A periodic check of the
system calibration is recommended following the procedures explained
under Calibration Check. The Series 616W Transmitter is not field
serviceable and should be returned, freight prepaid, to the factory if
repair is required. Please enclose a description of the problems
encountered plus any available application information. Contact
customer service to receive a return goods authorization number before
shipping.
SPAN
ADJUST
ZERO
ADJUST
Fig. K
E-43-W:E-43-W(616) 6/2/10 9:17 AM Page 3