when using attenuators, do not go to very top of raw ampl rangeINSTRUMENT_5_0_2

3 files changed, 18 insertions, 0 deletions

diff --git a/device-functions.c b/device-functions.c
index 464079c..203af45 100644
--- a/device-functions.c
+++ b/device-functions.c
@@ -2715,6 +2715,18 @@ int Set_VI_Control(int parameter,int channel,float new_ampl,int *point_found,int
 			} else {
 				use_atten = globals.Flash.attenuators[channel][*atten_range];
 			}
+
+			// Limit max voltage in attenuator mode to 93% of full maximum,
+			// to avoid the region in AVPs where PW shifts at high amplitudes
+			float max1 = fabs(globals.Flash.min_ampl[channel]);
+			float max2 = fabs(globals.Flash.max_ampl[channel]);
+			if (max2 > max1) {
+				max1 = max2;
+			}
+			if ((use_ampl * use_atten) > 
+			    (globals.Flash.atten_percent_max_ampl[channel] * max1)) {
+				continue;
+			}
 		}
 
 		for (range_i=starting_range; (range_i<max_ranges) && (!*point_found || top_range_only); ++range_i) {	/* use non-all-zero ranges */
diff --git a/flash.c b/flash.c
index 8f0154b..1282eff 100644
--- a/flash.c
+++ b/flash.c
@@ -773,6 +773,8 @@ static void initFlashValues(FlashStruct *mem)
 		for (j=0;j<max_attens;j++) {
 			mem->attenuators[i][j] = 0.0;
 		}
+
+		mem->atten_percent_max_ampl[i] = 0.93;
 	}
 
 	mem->relay_delay_in_sec=0.5;
diff --git a/globals.h b/globals.h
index e703617..ca50fdf 100644
--- a/globals.h
+++ b/globals.h
@@ -707,6 +707,10 @@ typedef struct {
 									//              for 15 dB, use 5.62
 									//		for 10 dB, use 3.16
 
+	float atten_percent_max_ampl[max_channels];			// addr 10134 - normally 0.93
+									// don't use higher ampls in AVPs,
+									// where PW shifts near max ampl
+
 	char spare_end;
 
 	char flash_end;