B-6
SLA7900 Series
Installation and Operation Manual
X-TMF-SLA7900-MFC-eng
Part Number: 541B022AHG
August, 2009
Section B
Zero Drift Diagnostic on SLA7950S
Step 2 – Select the type of Brooks MFC to be configured
by using the Select product pull-down. The
ZDDCT will attempt to communicate with the
connected device, verify that the device has
the ZDD feature enabled, and will then read
and display the ZDD configuration parameters.
If the ZDDCT cannot communicate with the
connected device, the error window shown
below will be displayed. Verify that the device
is powered, that the device is properly
connected and that the device is connected to
the selected serial port.
If the ZDDCT detects that the connected device
does not have the ZDD feature enabled, the
error window shown below will be displayed.
Contact your Brooks Instrument representative
to find out how to enable the ZDD feature in
your device.
Step 3 – Configure the parameters that control the
functionality of the ZDD features. The effect of
each configuration parameter on the
functionality of the Zero Drift Diagnostic along
with the range of valid values is detailed below:
Enable – Enables the reporting of drift beyond
allowed limits detected by the Zero Drift
Diagnostic. The user may select Disabled,
Warning, or Alarm. When set to Warning, the
Alarm LED will display the specified flash code
in Green when drift has been detected. When
set to Alarm, the Alarm LED will display the
specified flash code in Red.
Flash Code – This parameter sets the code
that is flashed on the Alarm LED when a drift
condition has been detected. The code is
displayed as a set of flashes at a ½ second
interval followed by a 1 second interval. To
determine the alarm type, observe the Alarm
LED until the 1-second interval occurs then
count the number of flashes before the next 1-
second interval. The default value for Flash
Code is 13.
Latching Enable – If selected, the warning/
alarm condition will displayed, even if the Zero
Drift condition goes away. This latched warning/
alarm condition is cleared at the end of each
Interlock Delay.
