Dwyer 7000 - Manual (Page 3)

WIRE LENGTH
The maximum length of wire connecting transmitter and receiver is a
function of wire size and receiver resistance. Wiring should not contribute
to more than 10% of receiver resistance to total loop resistance. For
extremely long runs (over 1000 feet), choose receivers with higher resis-
tance’s to minimize size and cost of connecting leads. When the wiring
length is under 100 feet, lead wire as small as 22 awg can be used.
MULTIPLE RECEIVER INSTALLATION
An advantage of the standard 4-20 mA DC output signal provided by the
7000 Spirahelic
® Pressure Indicating Transmitter is that any number or
receivers can be connected in series in the current loop. Thus, an A-701
digital readout, an analog panel meter, a chart recorder, process control-
ling equipment, or any combination of these devices can be operated
simultaneously. It is necessary only that each be equipped with a stan-
dard 4-20 mA input and proper polarity of the input connections be
observed when inserting the device into the current loop. If any of the
receiving devices displays a negative or downscale reading this indicates
that the signal input leads are reversed.
MAINTENANCE
Upon final installation of the Series 7000 Spirahelic
® Pressure Indicating
Transmitter and the companion receiver, no routine maintenance is
required. A periodic check of the system calibration is recommended.
The Series 7000 Spirahelic
® Pressure Indicating Transmitter is not field
serviceable and should be returned freight prepaid, to the factory (listed
below) if repair is required (field repair should not be attempted and may
void warranty).
Dwyer Instruments, Inc.
Attn: Repair Department
102 Highway 212
Michigan City, IN 46360
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