自定义读取接口&自定义写入接口

client.go

@@ -793,7 +793,7 @@ func (mc *ModbusClient) WriteRegisterWithRes(addr uint16, value uint16) (bytes [
 	req.payload = append(req.payload, uint16ToBytes(mc.endianness, value)...)
 
 	// run the request across the transport and wait for a response
-	res, err = mc.executeRequest(req)
+	res, err = mc.executeRequestWithRes(req)
 	if err != nil {
 		return
 	}
@@ -1205,7 +1205,7 @@ func (mc *ModbusClient) readRegistersWithFunctionCode(addr uint16, quantity uint
 	// 16 * 16 * 40
 	if quantity > 10240 {
 		err = ErrUnexpectedParameters
-		mc.logger.Error("quantity of registers exceeds 1024")
+		mc.logger.Error("quantity of registers exceeds 10240")
 		return
 	}
 
@@ -1401,3 +1401,29 @@ func (mc *ModbusClient) executeRequest(req *pdu) (res *pdu, err error) {
 
 	return
 }
+
+func (mc *ModbusClient) executeRequestWithRes(req *pdu) (res *pdu, err error) {
+	// send the request over the wire, wait for and decode the response
+	res, err = mc.transport.ExecuteRequestWithRes(req)
+	if err != nil {
+		// map i/o timeouts to ErrRequestTimedOut
+		if os.IsTimeout(err) {
+			err = ErrRequestTimedOut
+		}
+		return
+	}
+
+	// make sure the source unit id matches that of the request
+	if (res.functionCode&0x80) == 0x00 && res.unitId != req.unitId {
+		err = ErrBadUnitId
+		return
+	}
+	// accept errors from gateway devices (using special unit id #255)
+	if (res.functionCode&0x80) == 0x80 &&
+		(res.unitId != req.unitId && res.unitId != 0xff) {
+		err = ErrBadUnitId
+		return
+	}
+
+	return
+}