Peaktronics DHC Series User Manual

25
continues normal operation by reading the Position
parameter (00B8 DOUB), which shows a value of 33.62%
open ($0D22) in step 1 and a value of 33.89% open
($0D3D) in step 2.
Between steps 2 and 3, the system determines that
the node 01 DHC needs to be overridden, which takes place
in step 3. The first line in step 3 shows the bus setting the
PACS
®
Command Input value to the desired override
position of 10.00% ($03E8). The second line shows the
PACS
®
OR Command ($6A) using a value of $01 (0000
0001 binary) to set bit 0 of the PACS
®
Control Register
parameter to "1". This instructs the DHC controller to use
the 10.00% override value instead of its analog input signal.
Note that the OR command leaves bit 7 in its previous state
of "1".
Step 4 continues the normal monitor operation,
except that the PACS
®
Control Register parameter shown
in the first line returns a value of $81 (1000 0001 binary) to
indicate that the DHC is being controlled by the PACS
®
Command Input value. The second line shows the
Position parameter returning a value of 10.03% ($03EB),
indicating that the DHC is responding to the override
command value. If bit 0 of the PACS
®
Control Register
had been "0", that would have indicated that the bus did not
access node 01 within the timeout period of 20 seconds. In
that case, the bus will need to set bit 0 to "1" again for
override operation to occur. Note that the PACS
®
Command Input value does not need to be rewritten
unless power is lost to the DHC, which would be indicated
by bit 7 of the PACS
®
Control Register being "0".
Between steps 4 and 5, the system determines that
the override operation is no longer needed. In step 5, the
bus terminates override by clearing bit 0 of the PACS
®
Control Register. The PACS
®
AND Command ($68) uses
a value of $FE (1111 1110 binary) to clear bit 0 to "0".
Step 6 shows a return to normal operation. Bit 0 of
the PACS
®
Control Register reads "0" in the first line,
while the Position parameter reads 33.29% ($D01). This
indicates that the DHC controller is using the analog input
signal again.

Peaktronics DHC Series Specifications

General

Brand	Peaktronics
Model	DHC Series
Category	Controller
Language	English