Iphone和Ipad上CorePlot库的不同行为

我正在尝试使用CorePlot库版本1.5.1绘制图形，当应用程序在Ipad上运行时可以，但是当它在Iphone上运行时，图形没有动画效果，并且以下错误出现在调试控制台中

Assertion failure in -[CPTXYPlotSpace setXRange:], /Users/eskroch/Projects/Core Plot/framework/Source/CPTXYPlotSpace.m:377

动画图形代码：

-(void)newData:(NSTimer *)theTimer
{
[Utils logClassObject:self andMethod:_cmd];
if(_beacon)
{
    CPTGraph *theGraph = layerHostingView.hostedGraph;
    CPTPlot *thePlot   = [theGraph plotWithIdentifier:kPlotIdentifier];

    if ( thePlot ) {
        if(_isDrawing)
        {
            if ( _arrayOfRSSI.count >= kMaxDataPoints ) {
                [_arrayOfRSSI removeObjectAtIndex:0];
                [_arrayOfTime removeObjectAtIndex:0];
                [thePlot deleteDataInIndexRange:NSMakeRange(0, 1)];
            }

            CPTXYPlotSpace *plotSpace = (CPTXYPlotSpace *)theGraph.defaultPlotSpace;
            NSUInteger location       = ([[_arrayOfTime lastObject] intValue] >= kMaxDataPoints ? [[_arrayOfTime lastObject] intValue] - kMaxDataPoints : 0);

            CPTPlotRange *oldRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromUnsignedInteger( (location > 0) ? location : 0 )
                                                                  length:CPTDecimalFromUnsignedInteger(kMaxDataPoints)];
            CPTPlotRange *newRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromUnsignedInteger((location>0 || ([[_arrayOfTime lastObject] intValue] >= kMaxDataPoints))?(location==0?5:location+5):location)
                                                                  length:CPTDecimalFromUnsignedInteger(kMaxDataPoints)];

            [CPTAnimation animate:plotSpace
                         property:@"xRange"
                    fromPlotRange:oldRange
                      toPlotRange:newRange
                         duration:CPTFloat(1.0 / 20)];


            [_arrayOfRSSI addObject:@(_beacon.rssi)];
            [_arrayOfTime addObject:@(currentIndex*5)];

            [thePlot insertDataAtIndex:_arrayOfRSSI.count - 1 numberOfRecords:1];
            AppDelegate *delegate = (AppDelegate*)[[UIApplication sharedApplication]delegate];
            [delegate.csvData appendFormat:@"%@;", _macAddress!=nil?[Utils stringToHex:_macAddress]:@"0"];

            [delegate.csvData appendFormat:@"%d;",5*currentIndex];
            [delegate.csvData appendFormat:@"%d;\n", (int)_beacon.rssi];
        }

        currentIndex++;
    }
}
}