CMU-24VDC-ITL Cabinet Monitor Unit
Operations Manual
Eberle Design Inc.
Page 5
CMU-24VDC Power Fail resets the LFSA-R, the SB #3 timeout count will be reset to two,
such that the next SB #3 timeout results in a LFSA-R.
A SB #3 timeout failure during the programmed Minimum Flash time or during a CMU-
24VDC Power Failure will not cause a FSA.
2.4 TYPE 62 FSA MESSAGE
If the “N” bit is set in a Type 62 message, the CMU-24VDC will react by causing a NFSA.
The NFSA will remain until the receipt of a Message 62 with the “N” bit cleared or until the
CMU-24VDC is reset by a Unit Reset or CMU-24VDC Power Fail. The NFSA will last for
the programmed Minimum Flash time at a minimum.
If the “L” bit is set in a Type 62 message, the CMU-24VDC will react by causing a LFSA.
2.5 LACK OF SIGNAL INPUTS MONITOR
The CMU-24VDC will detect the absence of a required signal voltage on all the inputs of a
channel OR the absence of any required channel load current. For voltage purposes a
required signal on the Green OR Yellow OR Red inputs associated with a channel will be
considered as that channel being Voltage Active. For load current purposes a total channel
load current above the programmed threshold for a channel will be considered as that
channel being Current Active. When a channel is not Voltage Active OR Current Active for
less than 700 milliseconds, the CMU-24VDC will not cause a LFSA. When a channel is not
Voltage Active OR Current Active for greater than 1000 milliseconds, the CMU-24VDC will
cause a LFSA. When a channel is not Voltage Active OR Current Active for more than 700
milliseconds but less than 1000 milliseconds, the CMU-24VDC may or may not cause a
LFSA.
The Current Sense Unit (CSU) monitor function is hardwired to the maximum of 28 physical
channels, thus Virtual Channels do not have CSU monitoring capability. The CSU monitor
function must be disabled for any physical channel that has an input remapped to a Virtual
Channel.
Lack of Signal Input monitoring will be disabled for all channels when the MC COIL
STATUS input is not active. There is programming in the Datakey to disable Lack of Signal
Input monitoring on a per channel basis.
Lack of Signal Input monitoring will also be disabled for any channel which has the DARK
CHANNEL MAP bit set to "1" in the Datakey programming for the DARK CHANNEL MAP
addressed by the DARK CHANNEL MAP SELECT bits in a Type 61 message.
2.6 MULTIPLE INPUT MONITOR
The CMU-24VDC will detect the presence of an active signal on two or more inputs of a
channel. When the presence of an active signal on two or more inputs of a channel is
detected for less than 200 milliseconds, the CMU-24VDC will not cause a LFSA. When the
presence of an active signal on two or more inputs to a channel is detected for 450
milliseconds or more, the CMU-24VDC will cause a LFSA. When the presence of an active
signal on two or more inputs to a channel is detected for more than 200 milliseconds but
less than 450 milliseconds, the CMU-24VDC may or may not cause a LFSA.
Multiple Input monitoring may anticipate and prevent a possible conflicting signal display in
the intersection in the event that a proceed signal on the current phase hangs up and is
constantly detected as active. An open or no load condition (i.e., burned-out bulb) may be
also detected as an active signal depending on the output impedance characteristics of the
load switch (i.e. load switch leakage current), and may cause a Multiple Input Fault.
