Pellistor input (Optional)
The Pellistor board is connected to SK2 on the main circuit board once jumpers A to
E are removed (see Appendix D). Two additional PCB pillars support the top edge of
the circuit board. A single DIL switch allows the drive current ranges and Pellistor
sensitivities to be set.
Setting Pellistor drive current
There are two drive current ranges as detailed in table 3. According to the type of
Pellistor connected SW1 needs to be either ‘ON’ or ‘OFF’.
Function SW1
A
SW1
B
SW1
C
SW1
D
Current – adjust VR2
95 – 195mA ON X X X
190 - 350mA OFF X X X
Full scale sensitivity – adjust VR3
7 – 64mV X ON OFF OFF
55 – 113mV X OFF ON OFF
104 – 162mV X OFF OFF ON
155 – 121mV X OFF OFF OFF
Table 3
Connect an ammeter between terminal 9 of the main circuit board and the detector of
the Pellistor. Adjust VR2 to set the drive current. Allow the current to stabilise before
removing the DVM.
Warning – ensure that the control panel is switched off during the connection
and disconnection of the ammeter.
Pellistor zero calibration
Connect a DVM between test TP1 and TP2. Adjust VR1 on the pellistor board until
the DVM reads 800mV ± 20mV. If a display is fitted to the control unit then the
display will display zero.
Pellistor span calibration (control unit with display)
The calibration is performed by using the coarse adjust potentiometer (VR3) on the
Pellistor circuit board and FSD (VR1) on the main circuit board.
Issue 4 03/09/04
13 of 29
To Next Page
Loading...
Need help?
General
