RECTANGULAR BALER

Abstract: In a rectangular baler (11) a microprocessor (10) based control circuit monitors the loads registered by right-hand and left-hand conrod load cells (12, 14), the conrod load cells measuring the force applied to a plunger for compacting crop material. The microprocessor (10) produces output signals to control the baler (11) in accordance with the loads sensed by the cells (12, 14). On a stroke of the plunger, a predetermined interval, for example one-quarter second, is tolled after one cell registers a load. If the second cell does not register a load within that interval it is assumed to be faulty. In order to permit continued operation of the baler, the output of the good cell is assumed to be, and is used by the microprocessor as if if were, the output of the faulty cell.

Description: This invention relates to rectangular balers. US-A-4,624,180 discloses a microprocessor-based control circuit for controlling a large rectangular baler by sensing the load placed on load cells as a plunger compresses crop material into bales in the bale case of the baler. When a load cell fails on such a baler, the unit must be operated manually. This is inconvenient, causes down-time, and results in lower density bales. The present invention is defined in the appended claims and provides a microprocessor-controlled rectangular baler in which the microprocessor is programmed to test for a load on a second load cell within a predetermined interval, for example 1/4 second, after a load is sensed on a first load cell. If the second load cell does not show a load within that 1/4 second or other interval of the first, a dynamic fault is indicated on a display. In addition, the value of the load sensed at the good cell is assumed to be the load on the faulty cell and this value is used by the microprocessor as the load on each of the two cells, so that control of the baler may continue. Thus the present invention provides a method and means for detecting failure of a load cell and, upon detection of a failure, using the value of the load sensed at one load cell as an assumed value of the load at the other load cell, whereby the microprocessor may continue to control the baler. A rectangular baler in accordance with the present invention will now be described in greater detail, by way of example, with reference to the accompanying drawings, in which:- Figure 1 illustrates conrod load waveforms for a left and a right connecting rod; and, Figure 2 is a block diagram of a known microprocessor-based control circuit for a rectangular baler. Figure 1 illustrates the output of a left-hand conrod load cell and a right-hand conrod load cell, the cells being located at plunger connecting rod bearings as shown in US-A-4,624,180 and US-A-4,627,341 which are incorporated herein by reference. In Figure 1 both load cells complete each of two cycles within 1/4 second of each other. However, on the third cycle the right-hand conrod load cell fails to cycle so that it does not cycle within 1/4 second of the time the left-hand conrod load reaches a low threshold. The microprocessor control circuit 10 (Figure 2) is identical in structure to control circuit illustrated in US-A-4,624,180. It monitors right-hand and left-hand conrod cells 12 and 14, controls tension rails 15 on the baler 11, and displays status and various parameters on an operator's panel 16. The microprocessor 10 executes an interrupt sequence IRQT about every 500 microseconds and if a peak of conrod loading is detected the program branches to a LOOP routine. During execution of the LOOP routine a LOGIC routine is called wherein macroinstructions set various flags in accordance with inputs read during a previous scan of the various inputs to the microprocessor. The portions of these routines relating to the present invention are attached to this specification as an appendix. In the appendix, the flag 1701B is set if initialisation is complete and the logic detects a left conrod dynamic fault. Flags 1701C is set for 1/4 second if the logic detects a right conrod fault. The flags are tested during the next IRQT execution. Considering the left conrod, the right fault flag 1701C is tested at IRQT 25 and if it is set the program branches to MF1 where the left threshold flag IRQT 35A is set to 1 and the high threshold preset count in SYVR 30A is loaded into the right-hand load cell high threshold count location IRQT 12A. Next, the maximum left-hand load cell reading in IRQT 4A is transferred to IRQT 16A and IRQT 4A is cleared. A jump is then made to the LOOP routine. Steps IRQT 36, MF2 and IRQT 40 perform similar operations to the ones described above to check the right threshold. However, at the completion of these steps the routine jumps to LOOP 2. In LOOP, the right-hand conrod fault flag 1701C is tested and if its is not set, the program branches to LOOP 1. However, if 1701C is set IRQT 41A, the left slip count buffer, is cleared, the LOOP 18A, the dynamic failure flag, is set to all ones. This flag will cause the message "dF" to be displayed at the operators panel the next time the Main routine is executed. Next, the right conrod peak reading IRQT 17A is set to all ones before a branch is made to LOOP 2. In LOOP 2, the value in the accumulator is stored in LOOP 4A, the location for the left-hand conrod peak reading. This value will be all ones if LOOP 2 is entered from LOOP of the maximum IRQT 14A for the right-hand load cell is LOOP 2 is entered from IRQT 40. Subroutines LOOP 6 through LOOP 8 perform functions similar to LOOP through LOOP 2, the only difference being that they check for a right-hand conrod peak. LOOP 1 is entered if the test in LOOP shows that flag 1701C is not set. The value 080H is loaded into 1BP, the flags for left-hand dynamic conrod failure and left-hand conrod overload are cleared, and the left-hand conrod peak value in IRQT 16A is loaded into the accumulator so that it is stores in LOOP 4A when loop 2 is entered. Thus, is a conrod cell failure is detected, the load placed on the other conrod is assumed to be the load on the conrod with the failed cell. The microprocessor then uses this assumed value and continues its operation as described in US-A-4,264,180 patent.

Claims: A method of controlling the operation of a rectangular baler (11) having a microprocessor (10) for monitoring right-hand and left-hand plunger conrod load cells (12,14) and controlling the baler in accordance with the loads sensed by the cells, the method comprising the steps of: sensing the outputs of the load cells (12,14) for peak load, determining if a second of the load cells senses a load peak within a predetermined interval after a first of the load cells senses a load peak: and, using the sensed output of the first cell in place of the output from the second cell if the second cell does not sense a peak in order to calculate control signals for application to the baler (11), whereby continued operation of the baler is achieved even in the event of a load cell failure. A rectangular baler (11) having a microprocessor-based control circuit (10) for controlling operation of the baler (11), the control circuit (10) being operable to monitor right-hand and left-hand plunger conrod load cells (12,14) and controlling the baler (11) in accordance with the loads sensed by the cells (12,14), characterised in that the control circuit (11) further comprises means (10) for determining if a second of the load cells (12,14) senses a load peak within a predetermined interval after a first of the load cells senses a load peak and using the sensed output of the first cell in place of the output of the second cell if the second cell does not sense a peak, in order to calculate control signals for application to the baler (11), whereby continued operation of the baler is achieved even in the event of a load cell failure.

Inventors: STROSSER, RICHARD P.
Applicants: FORD NEW HOLLAND, INC. (A DELAWARE CORP.)
Application year: 1988
Main classification: A01F15
IPC codes: B30B9, A01F15