Dwyer DPM - Manual (Page 34)

Particulate Monitoring Systems
Installation & Operating Manual
Document No. 210-1003-M Page 27 ©2007
8.2 Control Unit Zero Check
The Zero Check will verify instrument zero calibration. The internal self check subsystem will
automatically perform the following procedure:
1. Electronic disconnect of the particulate sensor cable
2. Allow the reading to stabilize
3. Measure the reading and compare to the allowable zero tolerance
4. Electronic re-connect of the particulate sensor cable and resume normal operation.
There are four independent methods to activate the zero check:
Method Description
Power-Up
A zero check is automatically performed each time power is applied to
the control unit
Keypad
The operator may activate a zero check manually through the control
unit keypad. Reference Menu #2 setup tree for complete details.
Automatic
The control unit may be configured to automatically perform a zero
check on a period basis. A re-settable delay timer controls the time
period between self checks. The delay timer is set to 1 hour by default.
The delay timer is reset each time self checks are performed regardless
of the activation method.
Automatic self checks may be activated at preset hourly, daily and
monthly dates/times when connected to a computer running the
FilterWare Visualization application.
Remote
The operator may activate a zero check manually when connected to a
remote computer running the FilterWare Visualization application.
Alternately, self checks may be independently activated from any
remote PC or PLC with Modbus® communication capability.