diff --git a/xgm.py b/xgm.py
index 61eba7e7a3c26304ef90ecd8da298ff0dbaa3d24..59f2dac2d359cac236effff394feca38656e7dcd 100644
--- a/xgm.py
+++ b/xgm.py
@@ -573,7 +573,7 @@ def getTIMapd(data, mcp=1, use_apd=True, intstart=None, intstop=None,
             print(f'Warning: apd parameter was set to record 1 pulse out of {period} @ 4.5 MHz ' +
                   f'but XFEL delivered 1 pulse out of {period_from_bunch_pattern}.')
         maxPulses = data['npulses_sase3'].max().values
-        if period*pulseIdDim < period_from_bunch_pattern*maxPulses:
+        if period*pulseIdDim < period_from_bunch_pattern*(maxPulses-1):
             print(f'Warning: Number of pulses and/or rep. rate in apd parameters were set ' +
                   f'too low ({pulseIdDim})to record the {maxPulses} SASE 3 pulses')
         peaks = data[f'MCP{mcp}apd']