Yesterday afternoon until 2 am, we had low range because the squeezing angle was not well tuned.  As Naoki has noted 78529 this can happen when the OPO PZT is at a lower voltage than we normally operate at. This probably could have been improved by running SCAN_SQZANG. 

I've edited the OPO_PZT_OK checker, so that it requires the OPO PZT to be between 70 and 110 V (it used to be 50 to 110V).  This might mean that sometimes the OPO has difficulty locking, (ie, 76642), which will cause the IFO to call for help, but that will avoid running with low range when it needs to run SCAN_SQZANG.