Push To Cal (Pin 6); Digital Return (Pin 7); Pin 8); Display Hold (Pin 9) - Omega DP461-S User Manual

16.6 PUSH TO CAL (PIN 6)

The Push To Cal feature is only available for the Strain Gage meter and the
Universal meter when configured for the BRIDGE mode.
This feature allows you to connect an external calibration resistor to P2-6
and P2-14 at the rear of the meter. NOTE: Use a one-way switch only.
If your selected calibration resistor is to be mounted externally (in series with
your switch), install a SHORT in place of R135. NOTE: This short is already
installed at the factory.
If your selected calibration resistor is to be mounted internally, solder it in the
holes of R35 on the input board. See Figure 5.6.

16.7 DIGITAL RETURN (PIN 7)

This is a non-isolated return to be used for the digital controls provided on
this P2 connector.
WARNING: THIS METER RETURN IS NOT ISOLATED FROM THE
SIGNAL INPUT AND SHOULD NOT BE CONNECTED TO EXTERNALLY-
GROUNDED DEVICES UNLESS ISOLATION IS PROVIDED EITHER AT
THE SIGNAL INPUT OR AT THIS EXTERNAL-LOGIC CONNECTION.
16.8 +5 V (PIN 8)
Up to 20 mA is available for driving external devices, but isolation should be
provided if there is a possibility of common mode (ground) currents, since
this supply is NOT isolated from the signal input.

16.9 DISPLAY HOLD (PIN 9)

Grounding this pin to P2-7 freezes the display value. However, the meter
continues to take new samples and update the other outputs, such as
Analog Output, BCD, Setpoints/Alarms, and Peak/Valley.
16.10 LOCKOUT EEPROM (AND ' ' M M E E N N U U ' ' BUTTON) (PIN 10)
Grounding this pin to P2-7 stops any configuration changes and new storage
into the non-volatile memory, and when in run mode does not allow entry
into the setup mode when the 'MENU' button is pressed.

16.11 PRINT COMMAND AND/OR RESET OF ALARMS (PIN 11)

Grounding this pin to P2-7 when "BUS.8=1" has been programmed will
initiate a meter printout via serial communications in the format previously
selected. If "ALC.8=1" it causes the alarm latches to reset.

16.12 NONSTANDARD RX (PIN 12) AND NONSTANDARD TX (PIN 13)

These two pins allow digital communications with the meter using 5 V CMOS
logic levels and RS-232 protocols and format. This access is normally
reserved for specialized equipment communication in a calibration lab or at
the factory.
External Control Lines
16
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