Elevation measuring using a Smarttool Circuit

(C) DL4MEA 08/1998

07.08.1998    creatio
12.01.1999    problem with background colour solved
03.03.1999    software packages added
20.09.1999    background of scanned pictures now ok, added new datasheet as delivered by SMARTTOOL Technologiesd

D: Dieses Bild zeigt eine Schaltung der amerikanischen Firma Smarttool. Es ist eine unabhängiger Neigungsmesser mit RS232-Ausgang, vergleichbar mit dem Innenleben einer digital anzeigenden Wasserwaage. Die Leiterplatte darunter trägt einen RS485-Treiber zur besseren Datenübertragung an den Steuerungsrechner.

Das Bild zeigt die Schaltung noch in einem PVC-Gehäuse, da es sich aber als sehr HF-empfindlich herausgestellt hat, ist der Einbau in ein schirmendes Metallgehäuse dringend zu empfehlen.

Zum einfachen Betrieb eines Smartlevel gibt es zwei Software: W9IP LEVEL.EXE oder das Original von Smarttool ST.EXE.

E: This picture is the Smarttool cirucit from USA. It is an independent inclination meter with a RS232 output. The PCB below the smarttool is equipped with a RS485 driver which gives a more safe data transfer to the control unit.

The picture acutally shows the smarttool inside of a plastic box, but due to its RF sensitivity, it should be mounted into a screening box.

There are two software packages available to use the Smartlevel or Smartool together with a PC:  W9IP LEVEL.EXE or ST.EXE. from Smarttool themselfes.


Manufactures Datasheet:



ISU Circuit Board -- Part No. 90104001


Range: full 360°
Serial port
0.00549° , binary; 0.01° , ascii;
at level and plumb
at other angles
+/- 0.1°
+/- 0.2°
Calibration points
Temperature coefficient
at level or plumb
at other angles
+/- 1 deg. 0.006° per ° C
0.012° per ° C
Repeatability +/- 0.1°
    (average over 360 degrees)
Noise +/- 0.02°
1717 Grant St.lSan ta Clara, California 95050

Phone: 408-653-1680 Fax: 408-653-1690 Email: [email protected]

A Division of Macklanburg-Duncan

ISU Circuit Board -- Part No. 90104001
Time constant: 0.4 seconds (typical)
Frequency response (-3dB): 0.4 Hz (typical)
Angle output rate: every 8/15 second (533 msec.)
Humidity sensitivity: Conformally coated
Width, circuit board
Height, sensor
2.60" (6.6 cm)
1.30" (3.3 cm)
1.25" (3.2 cm)
0.60" (1.5 cm)
Weight: 0.8 oz. (23 gm)
Power input:
current, operating
5.0 volts, DC
2 mA
10 uA
Serial port communications
    (RS-232 except for voltage levels):
baud rate
output impedance


5.0 volts
9600 baud
10K W

PWM output:
pulse width
5.0 volts
30 Hz, freerunning
varies 49.4 usec. per degree
Temperature range:
-30 to +55° C. (-22 to 131° F.)
-55 to +65° C. (-67 to 149° F.)
Options: 1. higher or lower accuracy versions
2. power auto-shutoff
3. 4-bit addressability (TXEN output may be used to enable tristate drivers)
Specifications subject to change without notice.

Specifications at 77° F. (25° C.) unless otherwise stated.


Additional Information: (click on the pictures, they are just small for presentation here but you've already loaded them)