ELECTRICAL CONNECTIONS
Shielded cable is recommended for control loop wiring. Electrical connections to the
Series 629C pressure transmitters are made to the terminal block located inside the
housing. Remove the screws and lift off the cover. Wire as shown in Figure 3 or 4. Use
Figure 3 for current output connection. Use Figure 4 for current output with optional
LCD display. If ordering pre-wired cable, black wire is negative (-) and red wire is
positive (+).
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 ft or 305 m), choose receivers with higher resistance to minimize size and cost
of connecting leads. When wiring length is under 100 ft (30.5 m), lead wire as small
as 22 AWG can be used.
Current (4 to 20 mA) Output Operation
– An external power supply delivering 10 to
35 VDC with minimum current capability of 40 mA DC (per transmitter) is required to
power the control loop. See Figure 3 for connection of the power supply, transmitter,
and receiver. The range of the appropriate receiver load resistance (RL) for the DC
power supply voltage available is expressed by the formula
INSTALLATION
1. Location:
Select a location where the temperature of the unit will be between
0 and 200°F (-18 to 93°C). Distance from the receiver is limited only by total loop
resistance (see electrical connections). The tubing feeding pressure to the instrument
can be practically any length required, but long lengths will increase the response
time slightly. Mount the instrument in a location that will not be subject to excessive
temperature, shock, or vibration.
2. Position:
A vertical position is recommended (pressure connections pointing
horizontally) since that is how all standard models are spanned and zeroed at the
factory. They can be used at other angles, but may require final zeroing. Due to
potential condensation buildup that may travel down conduit or cable and into the
housing, it is recommended to install with the electrical conduit or cable gland pointing
downward.
3. Pressure Connection:
Dual 1/4“ NPT pressure connections are provided. Use pipe
thread sealant tape or other suitable pipe joint compound when making connection to
the pressure source. Avoid excess sealant which could block the pressure passage.
When monitoring liquid pressures, air trapped in the lines can cause incorrect readings.
Bleed fittings or similar mechanisms should be used to bleed off any trapped air.
Optional 3-Way Valve
For applications where higher line pressures may be encountered at installation or
when it is necessary to remove the transmitter for maintenance without interrupting the
process, the optional three way valve is recommended. (See Figure 1)
Installation with 3-way valve option. Begin with valve V1 open and valves V2 and
V3 closed. (See Figure 2) Slowly open valves V2 and V3. Once the pressure has
stabilized and is equal on the high and low side of the transmitter, valve V1 can be
closed and normal operation can proceed.
To ensure proper pressures will be detected by the 629C, use the bleed fittings
provided with this package to free media of bubbles. Before applying pressure to the
process connections, turn V1 to the open position and back off either the low or high
side bleed hex nut. Next, apply pressure. After the flowing liquid is free of bubbles,
retighten the bleed hex nut.
Before removing the transmitter from operation, open valve V1, then close valves V2
and V3.
7-17/64 [184.66]
2-13/32
[60.96]
3-63/64
[101.02]
5-19/32
[142.11]
4-17/64
[108.33]
2-25/64
[60.84]
3 [76.19]
1-37/64
[40.14]
PRESSURE
TRANSMITTER
1
RECEIVER
2
3
4
SHIELD
COM
VIN
+
-
+
-
POWER
SUPPLY
10-35 VDC
WHITE
YELLOW
ORANGE
BLUE
BLACK
RED
SHIELD [TERM #4]
Com [TERM #2]
Vin [TERM #1]
POWER
SUPPLY
10-35 VDC
-
+
RECEIVER
-
+
LCD CONNECTOR
HI [+]
PRESSURE
CONNECTION
LOW [-]
PRESSURE
CONNECTION
UNIT BUTTON-PRESS TO TOGGLE THE
UNIT [PSID/BARD] ON THE LCD
ZERO BUTTON- PRESS AND
HOLD TO ZERO THE GAGE
TRANSMITTER CONNECTION INSTRUCTION:
- TURN OFF POWER SUPPLY.
- CONNECT THE POWER SUPPLY AND RECEIEVER TO Vin [TERM #1] AND Com
[TERM #2] OF THE GAGE AS SHOWN.
- INSTALL THE LCD'S CONNECTOR TO THE GAGE AS SHOWN.
- TURN ON POWER.
CAUTION: BE SURE TO TURN OFF POWER WHEN CONNECTING OR REMOVING
THE LCD CONNECTOR. FAILURE TO DO SO CAN RESULT IN GAGE DAMAGE.
Figure 1: 629C with Optional 3-Way Valve
Figure 2: Bleed Fitting Connections
Figure 3: Current Output Connection
Figure 4: Current Output with Optional LCD
BLEED FITTING
HIGH SIDE
BLEED FITTING
LOW SIDE
R
L
max =
vps - 10
20 mA DC
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