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Second Only
This is the setting to use if you have only one tacho connected and it is
connected to the Tacho 2 port on the GCM. This is the tacho that will be used
for all functions within the controller. Note: This tacho may be a 2-channel (i.e.
quadrature), but it is still considered one tacho.
Note: The Configuration settings should bet set to enable only Tacho 2 (see
Main Menu > Advanced Setup > Configuration > Tacho 2).
First (Pri) Second (Slip)
This setting requires that tachos be connected to both tacho ports on the GCM.
They may each be any of the allowable types (see Main Menu > Advanced
Setup > Tachos > Tacho n).
With this setting, the First tacho (connected to port 1) will be used for all
process control functions and the Second (connected to port 2) will be used to
detect belt slippage. This is done by monitoring the ratio of the signals from the
two tachos. Nominally it should be constant regardless of belt speed. However,
if the belt slips on the driving pulley (i.e. the head pulley), the ratio will change
and this can be detected and used to set alarms. If the ratio exceeds a settable
amount then the Logical output “Belt Slippage” will turn on (see Main Menu >
Advanced Setup > Tachos > Numeric Data > Max Allowed Ratio Diff).
This setting is most commonly used when there is a tacho connected to port 1
that is mounted to a tail pulley or some other idling pulley and another tacho
connected to port 2 that is mounted on the driving motor.
Second (Pri) First (Slip)
This setting is the same as the one above except the roles of the two tachos
are reversed.
First (Pri) Second (ZSpd)
This setting requires that tachos be connected to both tacho ports on the GCM.
They may each be any of the allowable types (see Main Menu > Advanced
Setup > Tachos > Tacho n).
With this setting, the First tacho (connected to port 1) will be used for all
process control functions and the Second (connected to port 2) will be used to
detect “Zero Speed”. The primary tacho will be used to calculate belt travel and
all other process functions. Pulses from the second tacho will be counted and if
a certain amount of belt travel occurs before a pulse from the second tacho is
received, then belt speed will be assumed to be slipping.
This setting is most commonly used when there is a tacho connected to port 1
that is mounted to the driving motor. This tacho is not directly measuring belt
speed and therefore may not detect true zero speed. For example in this setup
if the belt was to break, the motor could keep turning and without an additional
sensor, a loss of belt speed would not be detected. However, if a second
encoder, or some kind of sensor can be arranged to sense belt motion (i.e. a
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