Research Concepts RC2000A - Manual (Page 116)

116 RC2000A Dual Axis Antenna Controller Appendix I 2.6x Addendum
RC2000A only allowed the user to select either a Polarotor type polarization control device or a Rotating
Feed. If this altered behaviour of the AutoPol System causes a problem, set the Pol Control Equipment
code to One Port even if a two port feed is connected to the system. With the Pol Control? CONFIG
mode item set to One Port, version 2.6x (and later versions of the software) will behave in a manner
identical to previous versions of the software with respect to the AutoPol system.
4.5 Azimuth/Elevationa Axis Runaway Alarm Disable
The RC2000 is designed to interface to antenna mounts that employ pulse type position sensors on the
azimuth and elevation axis. A runaway alarm occurs when the antenna controller’s pulse position input
circuit detects a position pulse and the antenna has not been commanded to move and is not in a coast
interval immediately following a move.
The term ‘coast interval’ requires an understanding of the antenna controller’s anti-reversal system.
When a runaway alarm is triggered for a given axis the bottom row of the display will flash AZIM ALARM
or ELEV ALARM and further movement about that axis is disabled. Note that an overcurrent or jammed
condition can also trigger these alarms. The controller’s RESET mode will allow the user to determine
type of fault that triggered the alarm and also reset the alarm.
The anti-reversal system is controlled by the Azim Fast Deadband, Azim Slow Deadband, Elev Fast
Deadband, and Elev Slow Deadband CONFIG mode items. The operation of the anti-reversal system
is described by an example. Assume that the antenna is moving about the elevation axis in the upward
direction at fast speed (either as part of an automatic move or a manual jog operation). When the
antenna elevation drive is released the controller will not allow the antenna to move in the downward
direction until the drive has been idle for a time interval (in milliseconds) defined by the Elev Fast
Deadband CONFIG mode item. This keeps the antenna from rapidly reversing direction. If the antenna
was driven in the upward direction and was suddenly commanded to move in the downward direction,
for a short time the antenna would continue to move in the upward direction before reversing direction
and moving downward. Any elevation position pulses that occur between the time when the antenna is
commanded to move downward and actually begins moving downward will not be accumulated
properly. This will lead to an inaccurate elevation position count.
A ‘coast interval’ is the time immediately after a move in a given direction about a given axis when the
controller will not allow the antenna to move in the opposite direction about that axis. To repeat, a
runaway position count (for a given axis) is a position count that occurs when the antenna is not
commanded to move and is not in the coast interval immediately following a move (about the axis).
Previous versions of the RC2000A software (version 1.50 and earlier) would activate a runaway alarm
whenever a runaway position count was detected. The software modification described in this
addendum allows the user to modify the behavior of the runaway system to either disable runaway
errors or to require that more than one runaway count occur before the runaway alarm is triggered.
I-4.5.1 Configuring the Runaway Sensing System
The user can modify the operation of the runaway alarm sensing system via the values assigned to the
Azim Fast Deadband and Elev Fast Deadband CONFIG mode items. Each axis can be configured
separately.
If the value assigned to the Azim Fast Deadband CONFIG mode item ends in ‘40’ the controller will only
accumulate azimuth position counts when the antenna is moving about the azimuth axis or is in a coast
interval immediately proceeding an azimuth move. This effectively disables the runaway alarm for the
azimuth axis. The operation of the elevation runaway sensing system is configured via the Elev Fast
Deadband CONFIG mode item in a manner similar to that of the azimuth axis. Examples of ‘Fast
Deadband values that disable runaway sensing are 2040 and 940.
If the value assigned to the Azim Fast Deadband CONFIG mode item ends in ‘41’ through ‘49’ the
azimuth runaway count threshold will be assigned a value of 1 through 9, respectively. The azimuth
runaway count threshold is defined as the number of runaway counts which must be exceeded before
an azimuth runaway alarm is triggered. For example, if the Azim Fast Deadband CONFIG mode item
has a value of 1845 six runaway position counts must be accumulated before an azimuth runaway
alarm is triggered. The elevation axis is configured in a similar manner using the Elev Fast Deadband
CONFIG mode item.
Research Concepts, Inc. • 5420 Martindale Road • Shawnee, Kansas • 66218-9680 • USA www.researchconcepts.com