Teledyne ADFM Analog Output Module, Technical Manual, Page: 146 / 156

Appendix E
command will begin with “$1”, followed by a two or three letter
command and its parameters. The command syntax used to set the
analog output level of the DGH module is “AO+nnnnn.nn”, where
“nnnnn.nn” is the desired output level in milli-amps.
NOTE. Commands sent to the DGH modules MUST be entered precisely
correct, or the module will not respond to the command. Typographical
errors in entering the command cannot be corrected-attempting to do so
will result in an error message such as “?1 COMMAND ERROR” or “?1
SYNTAX ERROR”. Simply re-enter the command, taking particular care to
enter the command correctly. When a command has been correctly
entered, the DGH module will return the asterisk character (“*”) to
acknowledge the command.
NOTE. Rev B only: With switch SW2-2 set to the “ON” position, all installed
DGH modules are forced into their “Default” mode. In this mode, any
module should respond at 300 baud to any address and model number.
The module can then be programmed with the appropriate operating
parameters. Refer to the D3000/D4000 Users Manual or consult MGD
Technologies Inc. for more information.
E-3.2 Current Loop Calibration
Calibration of the output from any DGH module can easily be accom-
plished using the DGH software and a calibrated ammeter; no calibration
potentiometers or other hardware adjustments are required. The calibration
procedure is described in detail in Chapter 9 of the D3000/D4000 Users
Manual. The basic calibration procedure is as follows:
a. Start the DGH software, go to “Misc, Terminal Simulator”. Ensure
that the baud rate setting matches that programmed into the DGH
module
b. Connect the computer to the appropriate DB-9 connector.
c. Set the zero scale analog output value (4.0 mA) using the “AO”
command.
Example: Enter “$1AO+00004.00”
d. Measure the actual current output; if the output is in error send the
“WE” command followed by the “TMN” command. Repeat step 4
until the actual output is correct.
Example : Output value is measured as 4.02 mA instead of 4.0 mA.
Enter “$1WE”
Enter “$1TMN+00004.02”
Check revised output value, repeat if necessary.
page E-8 MGD Technologies, Inc.