To verify that the QOSEM readout has the expected sign convention, as detailed in D2500284, I injected a longtidual offset into the BBSS M1, via the QOSEM coils, and monitored M1, M2, M3 OSEMs. The QOSEM readout sign should be consistent with the BOSEMs and AOSEMs.

Figure 1 plots M1 F1_x, M2 LL, M3 UR and the test L injection into M1. Due to the location of these OSEMs they should all readout with the same sign. Here we see that the sign is consistent between the QOSEM, BOSEM and AOSEM for this given longitudal offset, verifying that the QOSEM sign convention is indeed as documented.