Reapply "Modbus: fix int to float conversion for int setter"

This reverts commit f9538edded.

util/modbus/register.go

@@ -1,6 +1,7 @@
 package modbus
 
 import (
+	"encoding/binary"
 	"errors"
 	"fmt"
 	"math"
@@ -137,11 +138,18 @@ func (r Register) Operation() (RegisterOperation, error) {
 		}
 	} else {
 		switch strings.ToLower(r.encoding()) {
-		case "int32s", "uint32s", "float32s", "ieee754s":
+		case "int32s", "uint32s":
 			op.Encode = func(v uint64) uint64 {
 				return v&0xFFFF<<16 | v&0xFFFF0000>>16
 			}
 
+		case "float32s", "ieee754s":
+			op.Encode = func(v uint64) uint64 {
+				b := make([]byte, 4)
+				encoding.PutFloat32LswFirst(b, float32(v))
+				return uint64(binary.BigEndian.Uint32(b))
+			}
+
 		default:
 			op.Encode = func(v uint64) uint64 {
 				return v