3. Two 1/4˝ female NPT pressure connections are furnished
to allow a choice of vertical or horizontal piping. The unused
port should be plugged. Use a minimal amount of thread
sealant. Too much could block the internal pressure pas-
sage.
CAUTION:
When installing fittings or pipe always us a sec-
ond wrench on the 1˝ pressure block DO NOT allow torque
to be transmitted from block to the gage case.
PNEUMATIC CALIBRATION TESTER
Use a dead weight tester or certified test gage with .125%
or better accuracy. The test gage range should be compa-
rable to the range of the Spirahelic
®
Pressure Indicating
Transmitter being checked. Connect the lines from the two
instruments to a tee and the third line from the tee to a con-
trollable source of pressure. Apply pressure slowly so pres-
sure equalizes throughout the system. Compare readings, if
gage being tested is found to need calibration, return it,
freight prepaid to the factory.
ELECTRICAL CONNECTIONS
CAUTION:
Do not exceed specified supply voltage ratings.
Permanent damage not covered by warranty will result. This
unit is not designed for 120 or 240 volt AC line operation.
Electrical connections to the Series 7000 Spirahelic
®
Pressure Indicating Transmitter are made at the rear of the
pressure gage. Feed stripped and tinned leads to the termi-
nal block screws shown below, refer to Figure A for loca-
tions of the terminal block, span and zero adjustments.
2-Wire Operation
- A external power supply delivering 10-
35 VDC with minimum current capability of 40 mA DC (per
transmitter), must be used to power the control loop. See
Figure B for connection of the power supply, transmitter,
and receiver. The range of the appropriate receiver load
resistance (R
L
) for the DC power supply voltage available is
expressed by the formula and graph in Figure C. Shielded
two wire cable is recommended for control loop wiring. if
grounding is required use negative side of control loop after
receiver see Figure B.
PRESSURE RANGING
Each standard Series 7000 Spirahelic
®
Pressure Indicating
Transmitter is factory calibrated to produce a 4 mA output
signal at zero pressure and a 20 mA signal at full scale. Use
the following procedure to check or adjust the output signal
calibration.
1. With the unit connected to its companion receiver and
power supply, an accurate milliam
m
eter should be inserted in
series with the current loop. A controllable pressure source
capable of achieving the necessary full scale pressure
should be connected to the pressure port of the transmitter
and teed to an accurate pressure gage or manometer. The
instrument should be calibrated in the same position in
which it will be used. Vertical mounting is recommended.
Bulletin A-33-A
page 2
MAXIMUM VALUE (1300 OHMS)
1400
1300
1200
1100
1000
900
800
700
600
500
400
300
200
100
50
0
5
10
15
20
25
30
35
40
OPERATING
REGION
RECEIVER RESIST
ANCE (OHMS)
R L MAX =
Vps-10.0
20mA DC
7000 SERIES
INDICATING
PRESSURE
TRANSMITTER
POWER
SUPPLY
10-35 VDC
mA
RECEIVER
SPAN ADJUST
ZERO ADJUST
TERMINAL BLOCK
SPIRAHELIC INDICA
TING
TRANSMITTER
MODEL:
RANGE:
SP
AN
ZER
O
7000
Fig. A
Fig. B
Fig. C
A-33-A 4/16/03 10:33 AM Page 2
