Specifications

Appendix D
D1500 Data Sheet
The D1500 Bridge Sensor Interface Modules contain all of the signal
conditioning functions necessary to interface Strain Gage and other resis-
tive bridge devices to an RS-232C or RS-485 computer port. Each module
contains excitation, an instrumentation amplifier, and a smart analog to
digital converter to convert resistive bridge sensor signals to ASCII data.
The user should become familiar with the generic D1000 information
described in the D1000 User’s Manual before attempting any of the
procedures outlined below.
Data Format
The ASCII output data is expressed in millivolts with 10 microvolt resolution.
For Example:
Command: $1RD (Read Data)
Response: *+00012.34
In this case, the output data is 12.34 millivolts.
Modules that are configured for ±30mV and have a usable span of ±60mV.
Modules configured for ±100mV have a usable span of ±120mV. The extra
overhead is used to trim any bridge offsets. Modules configured for 1-6V
have a usable span of 0-6V with a resolution of 1mV.
Setup Data
The factory setup for all versions of D1500 modules is 310701C2
Sensor Connections
See Figure 1 for the proper bridge sensor connections. Shields or grounds
should be connected to the -Excitation terminal.
Offset Trim
The D1500 modules do not provide any means of trimming the analog offset
of the sensor bridge. However, sensor offsets may be nulled from the output
data with the Trim Zero (TZ) command. This method of trimming is
convenient because the offset may be trimmed through the communications
port at any time. There is no need to have access to the module since the
trimming is performed remotely.
The input signal conditioning circuitry of the D1500 modules have a wide
input range to accommodate large sensor offsets without the need for
external trims. Modules rated for ±30mV. have an input range capability of
±60mV. Modules rated for ±100mV have an input range of ±120mV.