Added setSyncDelta method to the library

rcvd.js

@@ -16,6 +16,7 @@ RCVD = (function(nav) {
     }),
     watchModel = '',
     localgatt = null, //local GATT reference for disconnection
+    syncDelta = 500, //the delta value (in milliseconds) to make up for BLE transmission latency, 500 ms by default
     TD = new TextDecoder(),
     ids = s => `26eb00${s}-b012-49a8-b1f8-394fb2032b0f`,
     scanids = ['00001804-0000-1000-8000-00805f9b34fb', ids('0d')],
@@ -83,7 +84,7 @@ RCVD = (function(nav) {
 
     plgen = k => [...Array(6)].map((a,i)=>[k,i]), //property list generator
     cyclePresyncProperties = _ => new Promise((res, rej) => {
-      var slist = [...plgen(30),...plgen(31)]
+      var slist = [...plgen(30),...plgen(31)] //full property list for primary targets, GW-B/GMW-B models
       if(watchModel.indexOf('OCW') > 5)
         slist = [[30,0],[30,1]]
       else if(watchModel.indexOf('B2100') > 5 || watchModel.indexOf('B001') > 5 || watchModel.indexOf('DW-B5600') > 5 )
@@ -122,10 +123,10 @@ RCVD = (function(nav) {
     getModel: _ => watchModel,
     rawRead: execReadCmd,
     rawWrite: execWriteCmd,
+    setSyncDelta: val => {syncDelta = +val; if(isNaN(syncDelta)) syncDelta = 500},
     sync: dObj => new Promise((res, rej) => {
       cyclePresyncProperties().then(_ => {
-        //set to the next second to make up for latency
-        var d = dObj || new Date(Date.now() + 500), year = d.getFullYear()
+        var d = dObj || new Date(Date.now() + syncDelta), year = d.getFullYear()
         execWriteCmd(Uint8Array.from([
           9,
           year&255, year>>>8,