Filter Wheel Commands - Sutter Instrument LAMBDA 10-B Operation Manual

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Filter Commands. These commands select the desired filter position and switching
◼
speed. The filter position and switching speed are each specified by the encoding of
specific bits within the command byte.
• The filter position is specified in the least significant 4 bits (nibble) of the byte (Bits 3,
2, 1, and 0), providing value range of 0 through 9. Because only 10 possible filter
positions are encoded in these bits, they are effectively encoded in Binary Coded
Decimal (BCD) format, leaving the values of 10 through 15 (decimal) available for use
by Shutter and Special commands.
•
The filter switching speed is specified in the least significant 3 bits within the most
significant nibble of the byte (Bits 6, 5, & 4), providing a value range of 0 through 7.
These bits are interpreted as the filter switching speed only if the bits in the lower
nibble of the byte contain a value of 0 through 9, specifying the filter position as
described previously
• The filter wheel selection is specified in the most significant bit of the byte (Bit 7).
Because the LAMBDA 10-B supports only one filter wheel, Bit 7 of the command byte
is always set to 0.
Shutter Commands. These commands control the open and closed states of shutters as
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well as various modes in which
Special Commands. These commands are used to control various aspects of the controller
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that are not specifically related to either filters or shutters. Some of these commands are
also used to obtain status and configuration information of the controller.
The microprocessor in the controller is programmed to distinguish between these two types
of Input Commands based on the bit pattern of the Command and will respond accordingly.
These two types of Commands are discussed in more detail in the following sections.

5.2 Filter Wheel Commands

A byte command sent to the controller that contains a value from 0 through 121 decimal (00
through 79 hexadecimal) is interpreted as a Filter Wheel Command. Within a Filter Wheel
Command byte, three parameters are encoded: Filter Wheel, Speed, and Position. The
accommodation of these three parameters within a single byte is accomplished by breaking
up the byte into three parts: two bit groups, and one single bit, as follows.
WHEEL BIT: In Sutter's Lambda 10-2 Filter Wheel this bit selects the filter wheel to
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which the Filter and Speed commands will be directed. The model 10-B filter wheel,
however, does not support a second wheel and this bit should always be low. Some models
of the Lambda series of controllers support the connecting of two filter wheels at a time,
and thus the filter wheel bit (Bit 7) is used to select the filter wheel. The LAMBDA 10-B
controller, however, supports only one filter wheel, so the filter wheel bit (Bit 7) is always
0.
SPEED GROUP: These 3 bits select the speed of movement used in advancing to the
◼
next filter. The speed group is treated as a three-place binary number whose equivalent
decimal value, 0 through 7, correspond to the selected speed.
FILTER POSITION GROUP: This group consists of all 4 bits within the lower nibble of
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the byte (the least significant 4 bits of the byte). These 4 bits select the desired filter (i.e.,
the filter wheel position). This group is treated as a four-place binary number, with the
equivalent decimal values 0 through 9 corresponding to the selected filter position. These
four bits can also be thought of as containing a BCD (Binary Coded Decimal) value, since
Smart
Shutters can operate.
LAMBDA 10-B OPERATION MANUAL – REV. 1.20Q (20230227)