Texmate, Inc. Tel. (760) 598-9899 • www.texmate.com
Page 2
PM-35U Manual (P1)
Functional Diagram
1
2
3
4
5
6
7
8
A
B
C
D
E
F
H
J
K
L
9
10
VOLTAGE
DIVIDER
SIGNAL
HIGH
INPUT
SIGNAL
HIGH
INPUT
SIGNAL
LOW
INPUT
ANALOG
COMMON
REFERENCE
VOLTAGE
OUTPUT
REFERENCE
INPUT
POWER
GROUND INPUT
+5VDC
SYSTEM
POWER INPUT
DECIMAL SELECTION
DISPLAY
TEST
+5V
BUFFER
J1
+5V
R9
18.2k
R10
2k
R8
9.53k
LOGIC
CIRCUITRY
R1
R2
R
220k
C5
0.1 F
3.5VDC
C1
F
1 V
C2
F
1 V
23
+5V
R 0k
C 0.22 F
INTEGRATOR COMPARATOR
C8
100 F
C
.0 F
R
100
R13
80
C
0.1 F
μ
Ω
μ
μ
μ
μ
μ
220k
Ω
Ω
R3
÷
OPTIONAL COMPONENTS
ARE SHOWN DOTTED
+
Connector Pinouts
The Texmate Model PM-35U inter con nects by means of a stan-
dard PC board edge connector having two rows of 10 pins, spaced
on 0.156" centers. Connector are available from Texmate, or from
almost any connector manu fac turer. Pro vi sion has also been made
for direct solder termination to the PC board, thus elimi nat ing the
need for a connector. Please note that the warranty will be void if
there is any damage due to soldering.
1
A
2
B
3
C
4 5 6 7 8 9 10
D E F H J K L
Calibration Pot
Component Side
Solder Side
10
L
9
K
8
J
7
H
6
F
5
E
4
D
3
C
2
B
1
A
DECIMAL SELECT COMMON
DECIMAL SELECT (1X.XX)
DECIMAL SELECT (1.XXX)
REFERENCE VOLTAGE OUTPUT
DISPLAY TEST
SIGNAL HIGH INPUT
VOLTAGE DIVIDER SIGNAL HIGH INPUT
SIGNAL LOW INPUT
POWER GROUND INPUT
+5VDC SYSTEM POWER INPUT
DECIMAL SELECT (1XX.X)
DECIMAL DECIMAL SELECT COMMON
DECIMAL SELECT (.1XXX)
REFERENCE INPUT
ANALOG COMMON
SIGNAL HIGH INPUT
VOLTAGE DIVIDER SIGNAL HIGH INPUT
SIGNAL LOW INPUT
POWER GROUND INPUT
+5VDC SYSTEM POWER INPUT
Pins A, C, 1 and 3- Decimal Select: Decimal points may be
dis played as required by connecting appropriate pin to Decimal
Select Common Pins B or 2.
Pins B and 2- Decimal Select Common: Decimal points are dis-
played as required by connecting Pins B or 2 to the appropriate
Decimal Select Pins A, C, 1, or 3.
Pin D- Reference Input: Reference voltage input for A to D con-
vert er. Normally supplied from Reference Voltage Output Pin 4
which is internally jumpered to Pin D by way of Junction J1. Pin D
may be used as an input for ratiometric measurements. Minimum
usable voltage is .05VDC with +4.0VDC being the maximum.
Pin E- Analog Common: 2.8V output referenced to +5V System
Power Input L, approxi2.2V output referenced to Power
Ground Input Pin K.
Pins F and 6- Signal High Input: Signal high input of A to D con
-
verter. Maximum overvoltage protection is 250VDC or 175VAC.
Pins H and 7- Voltage Divider Signal High Input: Signal high
input for voltages that require attenuation or scaling. Dividing
resistors R1 and R2 may be mounted internally for voltages up to
1200V max. Matched dividing resistors for 2V (1/10), 200V (1/100),
and 1200V (1/1000) ranges are available from Texmate. Shunt
resistors for current measurements up to 200mA may be internally
mounted in the R2 position. The current loop is then applied to
Signal High Input Pin F and returned through Pin J or Pin 8.
Pins J and 8- Signal Low Input: Signal low input of A to D con-
vert er. Maximum overvoltage protection is 250VDC or 175VAC.
Pins K and 9- Power Ground Input: Negative terminal of + 5VDC
power should be connected to Pin 9. All digital signals, decimal
points, display test, and overrange should be returned to this
ground point.
Pins L and 10- +5VDC System Power Input: Meter requires
regulated (±10%) 5VDC power at approximately 200mA.
Pin 4- Reference Voltage Output: Internal precision voltage
ref er ence. Standard output is 1.000V, adjustable to ±5% by R10
potentiometer. Usable voltages from .05V to 2.8V for special high
impedance scaling can be obtained by changing the value of inter
-
nal dividing resistors R8 and R9.
Pin 5- Display Test: All segments will light up when Pin 5 is con
-
nected to +5VDC System Power Input Pin L or Pin 10.
Component Layout
R13
R10
R9
R8
R7
C8
C7
C5
C4
C6
C2
C1
R6
R3
R4
R2
R1
Signal Conditioning Components
SPAN Potentiometer (Pot)
The SPAN pot is on the right side of the dis
-
play. Typical adjustment is 20% of the input
signal range.
Calibration Procedure
Apply power to the meter. Then with a precision DC reference source,
apply +1.900VDC be tween the Sig nal High Input Pin F and the Signal
Low Input Pin J. Adjust R10 po ten ti om e ter (on left side as viewed
from rear) until the display reads +1.9900V. Note: The voltage ap plied
in this case is for a ±1.999V F.S. meter. For other ranges, the voltage
applied should be similarly pro por tion ate to the particular full scale
voltage.
CAUTION: This meter employs high impedance CMOS inputs. Although internal
protection has been provided for several hundred volt overloads, the meter will
be destroyed if subjected to the high kilovolts of static discharge that can be
produced in low humidity environments. Always handle the meter with ground protection.
SOLDER SIDE
J1
COMPONENT SIDE
