Appendix A
PLMa Installation Drawing
These drawings and any specifications and concepts contained are the property of Phymetrix Inc., are issued
in strict confidence and shall not be used as the basis for the manufacture or sale of apparatus or services, or
reproduced or copied or transmitted in any form or by any means without written permission.
Unless other
wise specified dimensions ar
e in inches
.x +/- 0.020"
.xx +/-0.010"
.xxx +/- 0.005"
Title:
P
ar
t Number
:
Dr
a
wn b
y
:
D
at
e:
Scale:
P
age:
Rev
:
(
)
(
)
(
)
signal and wire colors
for molded cable:
1 - brown LOOP
+
2 - white
Tx out (TTL)
3 - blue LOOP
-
4 - black Rx in (TTL)
5 - green/yellow ground
to housing, isolated
from other 4 pins
T
op V
iew
with Molded Cable
Connector Installed
T
op V
iew
Molded connector
can be installed only
in this direction.
Screw terminal
connectors
can be oriented
as needed.
PLMa Installation Drawing
0
9/13/10
1:1
1 of 1
BB
+
+
-
-
5 to 28VDC
power supply
PLMa pins/sockets
1
3
5
V
sense
V
sense
V
analyzer
V
analyzer
R
sense
R
sense
R
sense
optional
shield
brown
blue
green/yellow
PLMa housing
could be connected
to Earth Ground
through pipes
the V
oltage across
Analyzer (V
a), min 5 VDC max 28 VDC.
Power rating of sensing resistor = * R ; Imax = 24mA
for a single device
Assuming = 250
Ω
Then = 0.024 * 0.024 * 250 = 0.144W
P
r
P
r
I
2
Since the voltage drop across the sense resistor can be
24 mA
* 250
Ω
=6V then in order to assure that V
a is not less than 5V
, the
power supply should be no less than 1
1V
. One should also consider the
total resistance of the cable when computing the voltage drops for the
power supply requirement.
thus should use a minimum 1/4 W
att rated resistor
Limitations:
Measurement Calculations:
The PLMa communicates the measured dewpoint to the user by
drawing (using) between 4 and 20 mA
of power
.
The user measures
this current with a sensing resistor
.
T
ypically the sensing resistor Rs is 250
Ω,
200
Ω
or 100
Ω
. Use a
precision resistor (1% or better) with a power rating of at least 1/4
W
att.
- 4
x 1000
x (H - L)
16
L +
PLMa Measured V
alue =
Where:
H = PV output Upper Range as set by HAR
T
command #35, read by #15
(factory d20
°
C)
L
= PV output Lower Range as set by HAR
T
command #35, read by #15
(factory default -100
°
C)
The Measured V
alue is calculated in the same units as the HAR
T settings for H and L.
If the PLMa housing is not
connected to Earth Ground
through the pipes then Ground
this side of the wire to Earth.
Do not ground both sides.
3/4-16
UNF-2A
1.798"
0.390"
1.410"
1.625"
1/4" NPT
0.880"
2.770"
1.898"
O-ring #1
17
1" OD x 0.103" CS
V
iton Hard
Connector Phoenix Contact P/N:
SACC-DSI-MS-5CON-L180SCO
Mates with
all M12 standard
connectors
Note: Sample Cell, Manifold or other Mating Surface
used with the 3/4"-16 threads must have a sealing
surface orthogonal to threads with a minimum of 1" dia.
spot-face, free of radial nicks and scratches. Maximum
thread countersink diameter of 0.790" to assure proper
sealing
1
2
3
4
5
0.195" dia.
cable
Use PTFE tape on
NPT
threads ONL
Y
.
Hex flats for 1.5" wrench
14