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On Broadcast write mbusd wait's for feedback and provides feedback #61

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dgoo2308 opened this issue Jul 29, 2020 · 5 comments
Closed

On Broadcast write mbusd wait's for feedback and provides feedback #61

dgoo2308 opened this issue Jul 29, 2020 · 5 comments

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@dgoo2308
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A write to unitId 0 is considered a broadcast and no devices should acknowledge although mbusd wait's for a response from servers, which it should not do as the servers are not allowed to acknowledge this.

This leads also to resends due to the time-outs and blocks the bus during that time () of waiting 3 times for 8 bytes.

Log unpatched:

Jul 28 18:47:19 bpi-iot-ros-ai mbusd[30096]: 28 Jul 2020 18:47:19 conn[192.168.1.55]: state now is CONN_RQST_FUNC
Jul 28 18:47:19 bpi-iot-ros-ai mbusd[30096]: 28 Jul 2020 18:47:19 conn[192.168.1.55]: state now is CONN_RQST_TAIL
Jul 28 18:47:19 bpi-iot-ros-ai mbusd[30096]: 28 Jul 2020 18:47:19 conn[192.168.1.55]: request: [00][05][00][e5][ff][00]
Jul 28 18:47:19 bpi-iot-ros-ai mbusd[30096]: 28 Jul 2020 18:47:19 conn[192.168.1.55]: state now is CONN_TTY
Jul 28 18:47:19 bpi-iot-ros-ai mbusd[30096]: 28 Jul 2020 18:47:19 tty: state now is TTY_RQST
Jul 28 18:47:19 bpi-iot-ros-ai mbusd[30096]: 28 Jul 2020 18:47:19 tty: state now is TTY_RESP
Jul 28 18:47:19 bpi-iot-ros-ai mbusd[30096]: 28 Jul 2020 18:47:19 tty: estimated 8 bytes, waiting 508332 usec
Jul 28 18:47:20 bpi-iot-ros-ai mbusd[30096]: 28 Jul 2020 18:47:20 tty: response timeout
Jul 28 18:47:20 bpi-iot-ros-ai mbusd[30096]: 28 Jul 2020 18:47:20 tty: attempt to retry request (1 of 3)
Jul 28 18:47:20 bpi-iot-ros-ai mbusd[30096]: 28 Jul 2020 18:47:20 tty: state now is TTY_RQST
Jul 28 18:47:20 bpi-iot-ros-ai mbusd[30096]: 28 Jul 2020 18:47:20 tty: state now is TTY_RESP
Jul 28 18:47:20 bpi-iot-ros-ai mbusd[30096]: 28 Jul 2020 18:47:20 tty: estimated 8 bytes, waiting 508332 usec
Jul 28 18:47:20 bpi-iot-ros-ai mbusd[30096]: 28 Jul 2020 18:47:20 tty: response timeout
Jul 28 18:47:20 bpi-iot-ros-ai mbusd[30096]: 28 Jul 2020 18:47:20 tty: attempt to retry request (2 of 3)
Jul 28 18:47:20 bpi-iot-ros-ai mbusd[30096]: 28 Jul 2020 18:47:20 tty: state now is TTY_RQST
Jul 28 18:47:20 bpi-iot-ros-ai mbusd[30096]: 28 Jul 2020 18:47:20 tty: state now is TTY_RESP
Jul 28 18:47:20 bpi-iot-ros-ai mbusd[30096]: 28 Jul 2020 18:47:20 tty: estimated 8 bytes, waiting 508332 usec
Jul 28 18:47:21 bpi-iot-ros-ai mbusd[30096]: 28 Jul 2020 18:47:21 tty: response timeout
Jul 28 18:47:21 bpi-iot-ros-ai mbusd[30096]: 28 Jul 2020 18:47:21 tty: attempt to retry request (3 of 3)
Jul 28 18:47:21 bpi-iot-ros-ai mbusd[30096]: 28 Jul 2020 18:47:21 tty: state now is TTY_RQST
Jul 28 18:47:21 bpi-iot-ros-ai mbusd[30096]: 28 Jul 2020 18:47:21 tty: state now is TTY_RESP
Jul 28 18:47:21 bpi-iot-ros-ai mbusd[30096]: 28 Jul 2020 18:47:21 tty: estimated 8 bytes, waiting 508332 usec
Jul 28 18:47:21 bpi-iot-ros-ai mbusd[30096]: 28 Jul 2020 18:47:21 conn[192.168.1.55]: state now is CONN_RQST_FUNC
Jul 28 18:47:21 bpi-iot-ros-ai mbusd[30096]: 28 Jul 2020 18:47:21 conn[192.168.1.55]: state now is CONN_RQST_TAIL

# read starts within the broadcast cycle after 2 seconds wait!
Jul 28 18:47:21 bpi-iot-ros-ai mbusd[30096]: 28 Jul 2020 18:47:21 conn[192.168.1.55]: request: [14][04][00][08][00][03]
Jul 28 18:47:21 bpi-iot-ros-ai mbusd[30096]: 28 Jul 2020 18:47:21 conn[192.168.1.55]: state now is CONN_TTY
Jul 28 18:47:21 bpi-iot-ros-ai mbusd[30096]: 28 Jul 2020 18:47:21 tty: response timeout

solution tested for FC05 broadcast

diff --git a/src/conn.c b/src/conn.c
index 6540da7..d52a83a 100644
--- a/src/conn.c
+++ b/src/conn.c
@@ -556,35 +556,50 @@ conn_loop(void)
 #ifdef DEBUG
           logw(7, "tty: request written (total %d bytes)", tty.txlen);
 #endif
-          state_tty_set(&tty, TTY_RESP);
-          switch (tty.txbuf[1]) {
-            case 1:
-            case 2:
-              tty.rxlen = 5 + (tty.txbuf[4] * 256 + tty.txbuf[5] + 7)/8;
-              break;
-            case 3:
-            case 4:
-              tty.rxlen = 5 + tty.txbuf[5] * 2;
-              break;
-            case 7:
-              tty.rxlen = 5;
-              break;
-            case 11:
-            case 15:
-            case 16:
-              tty.rxlen = 8;
-              break;
-            default:
-              tty.rxlen = tty.txlen;
-              break;
-          }
-          if (tty.rxlen > TTY_BUFSIZE)
-            tty.rxlen = TTY_BUFSIZE;
-          tty.timer += DV(tty.rxlen, tty.bpc, tty.speed);
+		  if (tty.txbuf[1]==5 && tty.txbuf[0]==0 )
+		  { // broadcast FC05
+			  // DANNY at work
+			  tty.rxlen=0;
+			  logw(5, "tty: Done, Broadcast");
+			  tty.timer=0;
+			  tcflush(tty.fd, TCIFLUSH);
+			  state_tty_set(&tty, TTY_PAUSE);
+			  state_conn_set(actconn, CONN_HEADER);
+			  continue;
+		  }
+		  else
+		  {
+				state_tty_set(&tty, TTY_RESP);
+			  switch (tty.txbuf[1]) {
+				case 1:
+				case 2:
+				  tty.rxlen = 5 + (tty.txbuf[4] * 256 + tty.txbuf[5] + 7)/8;
+				  break;
+				case 3:
+				case 4:
+				  tty.rxlen = 5 + tty.txbuf[5] * 2;
+				  break;
+				case 7:
+				  tty.rxlen = 5;
+				  break;
+				case 11:
+				case 15:
+				case 16:
+				  tty.rxlen = 8;
+				  break;
+				default:
+				  tty.rxlen = tty.txlen;
+				  break;
+			  }
+				
+			  if (tty.rxlen > TTY_BUFSIZE)
+				tty.rxlen = TTY_BUFSIZE;
+			  tty.timer += DV(tty.rxlen, tty.bpc, tty.speed);
 #ifdef DEBUG
-          logw(5, "tty: estimated %d bytes, waiting %lu usec", tty.rxlen, tty.timer);
+			  logw(5, "tty: estimated %d bytes, waiting %lu usec", tty.rxlen, tty.timer);
 #endif
-        }
+			}
+		}
       }
 
     if (FD_ISSET(tty.fd, &sdsetrd))

Log with patched version:

Jul 29 00:05:50 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:50 conn_loop(): select() returns 1
Jul 29 00:05:50 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:50 conn[192.168.1.55]: state now is CONN_RQST_FUNC
Jul 29 00:05:50 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:50 conn_loop(): select(): max_sd = 5, t_out = 000060:000000
Jul 29 00:05:50 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:50 conn_loop(): select() returns 1
Jul 29 00:05:50 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:50 conn[192.168.1.55]: read request fc 5
Jul 29 00:05:50 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:50 conn[192.168.1.55]: state now is CONN_RQST_TAIL
Jul 29 00:05:50 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:50 conn[192.168.1.55]: request: [00][05][00][e5][ff][00]
Jul 29 00:05:50 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:50 conn[192.168.1.55]: state now is CONN_TTY
Jul 29 00:05:50 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:50 tty: state now is TTY_RQST
Jul 29 00:05:50 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:50 conn_loop(): select(): max_sd = 4, t_out = 000060:000000
Jul 29 00:05:50 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:50 conn_loop(): select() returns 1
Jul 29 00:05:50 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:50 tty: written 8 bytes
Jul 29 00:05:50 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:50 tty: request written (total 8 bytes)
Jul 29 00:05:50 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:50 tty: Done, Broadcast
Jul 29 00:05:50 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:50 tty: state now is TTY_PAUSE
Jul 29 00:05:50 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:50 conn[192.168.1.55]: state now is CONN_HEADER
Jul 29 00:05:50 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:50 conn_loop(): select(): max_sd = 5, t_out = 000000:100000
Jul 29 00:05:50 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:50 conn_loop(): select() returns 0
Jul 29 00:05:50 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:50 tty: state now is TTY_READY
Jul 29 00:05:50 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:50 conn_loop(): select(): max_sd = 5, t_out = 000060:000000
Jul 29 00:05:51 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:51 conn_loop(): select() returns 1
Jul 29 00:05:51 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:51 conn[192.168.1.55]: state now is CONN_RQST_FUNC
Jul 29 00:05:51 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:51 conn_loop(): select(): max_sd = 5, t_out = 000060:000000
Jul 29 00:05:51 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:51 conn_loop(): select() returns 1
Jul 29 00:05:51 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:51 conn[192.168.1.55]: read request fc 4
Jul 29 00:05:51 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:51 conn[192.168.1.55]: state now is CONN_RQST_TAIL

# read after broadcast start
Jul 29 00:05:51 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:51 conn[192.168.1.55]: request: [14][04][00][08][00][03]
Jul 29 00:05:51 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:51 conn[192.168.1.55]: state now is CONN_TTY
Jul 29 00:05:51 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:51 tty: state now is TTY_RQST
Jul 29 00:05:51 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:51 conn_loop(): select(): max_sd = 4, t_out = 000060:000000
Jul 29 00:05:51 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:51 conn_loop(): select() returns 1
Jul 29 00:05:51 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:51 tty: written 8 bytes
Jul 29 00:05:51 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:51 tty: request written (total 8 bytes)
Jul 29 00:05:51 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:51 tty: state now is TTY_RESP
Jul 29 00:05:51 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:51 tty: estimated 11 bytes, waiting 509895 usec
Jul 29 00:05:51 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:51 conn_loop(): select(): max_sd = 4, t_out = 000000:509895
Jul 29 00:05:51 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:51 conn_loop(): select() returns 1
Jul 29 00:05:51 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:51 tty: read 11 bytes
Jul 29 00:05:51 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:51 tty: rx offset is 0
Jul 29 00:05:51 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:51 tty: read 11 bytes of 11, offset 0
Jul 29 00:05:51 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:51 tty: state now is TTY_PROC
Jul 29 00:05:51 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:51 tty: response read (total 11 bytes, offset 0 bytes)
Jul 29 00:05:51 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:51 tty: response is correct
Jul 29 00:05:51 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:51 tty: response: [14][04][06][05][53][05][53][fe][99][66][8d]
Jul 29 00:05:51 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:51 conn[192.168.1.55]: state now is CONN_RESP
Jul 29 00:05:51 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:51 tty: state now is TTY_PAUSE
Jul 29 00:05:51 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:51 conn_loop(): select(): max_sd = 5, t_out = 000000:100000
Jul 29 00:05:51 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:51 conn_loop(): select() returns 1
Jul 29 00:05:51 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:51 conn[192.168.1.55]: state now is CONN_HEADER
Jul 29 00:05:51 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:51 conn_loop(): select(): max_sd = 5, t_out = 000000:099446
Jul 29 00:05:51 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:51 conn_loop(): select() returns 0
Jul 29 00:05:51 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:51 tty: state now is TTY_READY
Jul 29 00:05:51 bpi-iot-ros-ai mbusd[18405]: 29 Jul 2020 00:05:51 conn_loop(): select(): max_sd = 5, t_out = 000060:000000

Result no more timeouts and a working solution.

  1. Please advice if that would be the apropriate place to do this.
  2. I only changed for FC05, according spec that should be for all writes.
@3cky
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3cky commented Jul 30, 2020

Thanks for pointing to this issue. The problem seems to be more complex though. Since Modbus/TCP neither specifies Unit ID 0 as a broadcast address nor defines the broadcast function at all, some of Modbus/TCP slaves (especially old ones) could use zero ID as a valid unicast slave address. But I agree mbusd should handle zero Unit ID more gracefully. I'll look into it.

@dgoo2308
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dgoo2308 commented Jul 31, 2020 •
edited
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@3cky Thanks.

Sorry but I thought mbusd was to provide a gateway to Modbus RTU, which (Modbus RTU) per spec defines that:

  • devices should not acknowledged a write on unitId 0
  • Clients should not wait for an acknowledge, nor retry a write on unitId 0.

I can say it does get very messy when devices e.g. arduino slaves start an action on a broadcast and repeated broadcasts come in.

PS: thank for sharing this lib, works like a charm.

3cky added a commit that referenced this issue Aug 13, 2020
@3cky
Do not wait for a reply for RTU broadcast address #61
461ce8b
@3cky
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3cky commented Aug 13, 2020

@dgoo2308 I've pushed the fix for RTU broadcast address writing, please test.

@dgoo2308
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@3cky so sorry for delay, I I'll try to squeeze the test in before my holiday next week otherwise it will be the second week of September.

I did notice for the tests that FC5 broadcast, write coil, is not tested.

@dgoo2308
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@3cky

looks very good, I did a quick test with libmodbus in c:

int main(int argc, const char * argv[])
{
	printf("ModBus version: %s\n",LIBMODBUS_VERSION_STRING);	
	modbus_t * CTX_Broadcast = modbus_new_tcp_pi("mbus-1.local", "502");
	if (CTX_Broadcast == NULL) {
		fprintf(stderr, "Unable to allocate libmodbus context\n");
		return -1;
	}

	if (modbus_connect(CTX_Broadcast) == -1) {
		fprintf(stderr, "Connection failed: %s\n", modbus_strerror(errno));
		modbus_free(CTX_Broadcast);
		return -1;
	}
	modbus_set_slave(CTX_Broadcast, 0);
	
/* output enable broadcast*/
	int r=modbus_write_register(CTX_Broadcast,13,0x1);
	if (r==-1)
	{
		fprintf(stderr, "Fail broadcast %s\n", modbus_strerror(errno));
	}
	modbus_close(CTX_Broadcast);
	modbus_free(CTX_Broadcast);
	return 0;
}

libmodbus still complains with Fail broadcast Operation timed out but that is an other problem to tackle.

results in a nice log without timeouts and no reply.

Aug 30 16:10:06 mbus-1 mbusd[912]: 30 Aug 2020 16:10:06 conn_loop(): select() returns 1
Aug 30 16:10:06 mbus-1 mbusd[912]: 30 Aug 2020 16:10:06 conn_open(): accepting connection from 192.168.1.75
Aug 30 16:10:06 mbus-1 mbusd[912]: 30 Aug 2020 16:10:06 queue_new_elem(): length now is 1
Aug 30 16:10:06 mbus-1 mbusd[912]: 30 Aug 2020 16:10:06 conn[192.168.1.75]: state now is CONN_HEADER
Aug 30 16:10:06 mbus-1 mbusd[912]: 30 Aug 2020 16:10:06 conn_loop(): select(): max_sd = 5, t_out = 000060:000000
Aug 30 16:10:06 mbus-1 mbusd[912]: 30 Aug 2020 16:10:06 conn_loop(): select() returns 1
Aug 30 16:10:06 mbus-1 mbusd[912]: 30 Aug 2020 16:10:06 conn[192.168.1.75]: state now is CONN_RQST_FUNC
Aug 30 16:10:06 mbus-1 mbusd[912]: 30 Aug 2020 16:10:06 conn_loop(): select(): max_sd = 5, t_out = 000060:000000
Aug 30 16:10:06 mbus-1 mbusd[912]: 30 Aug 2020 16:10:06 conn_loop(): select() returns 1
Aug 30 16:10:06 mbus-1 mbusd[912]: 30 Aug 2020 16:10:06 conn[192.168.1.75]: read request fc 6
Aug 30 16:10:06 mbus-1 mbusd[912]: 30 Aug 2020 16:10:06 conn[192.168.1.75]: state now is CONN_RQST_TAIL
Aug 30 16:10:06 mbus-1 mbusd[912]: 30 Aug 2020 16:10:06 conn[192.168.1.75]: request: [00][06][00][0d][00][01]
Aug 30 16:10:06 mbus-1 mbusd[912]: 30 Aug 2020 16:10:06 conn[192.168.1.75]: state now is CONN_TTY
Aug 30 16:10:06 mbus-1 mbusd[912]: 30 Aug 2020 16:10:06 tty: state now is TTY_RQST
Aug 30 16:10:06 mbus-1 mbusd[912]: 30 Aug 2020 16:10:06 conn_loop(): select(): max_sd = 4, t_out = 000060:000000
Aug 30 16:10:06 mbus-1 mbusd[912]: 30 Aug 2020 16:10:06 conn_loop(): select() returns 1
Aug 30 16:10:06 mbus-1 mbusd[912]: 30 Aug 2020 16:10:06 tty: written 8 bytes
Aug 30 16:10:06 mbus-1 mbusd[912]: 30 Aug 2020 16:10:06 tty: request written (total 8 bytes)
Aug 30 16:10:06 mbus-1 mbusd[912]: 30 Aug 2020 16:10:06 conn[192.168.1.75]: state now is CONN_HEADER
Aug 30 16:10:06 mbus-1 mbusd[912]: 30 Aug 2020 16:10:06 tty: state now is TTY_PAUSE
Aug 30 16:10:06 mbus-1 mbusd[912]: 30 Aug 2020 16:10:06 conn[192.168.1.75]: broadcast request sent
Aug 30 16:10:06 mbus-1 mbusd[912]: 30 Aug 2020 16:10:06 conn_loop(): select(): max_sd = 5, t_out = 000000:100000
Aug 30 16:10:06 mbus-1 mbusd[912]: 30 Aug 2020 16:10:06 conn_loop(): select() returns 0
Aug 30 16:10:06 mbus-1 mbusd[912]: 30 Aug 2020 16:10:06 tty: state now is TTY_READY
Aug 30 16:10:07 mbus-1 mbusd[912]: 30 Aug 2020 16:10:06 conn_loop(): select(): max_sd = 5, t_out = 000059:000000
Aug 30 16:10:07 mbus-1 mbusd[912]: 30 Aug 2020 16:10:07 conn_loop(): select() returns 1
Aug 30 16:10:07 mbus-1 mbusd[912]: 30 Aug 2020 16:10:07 conn_close(): closing connection from 192.168.1.75
Aug 30 16:10:07 mbus-1 mbusd[912]: 30 Aug 2020 16:10:07 queue_delete_elem(): length now is 0
Aug 30 16:10:07 mbus-1 mbusd[912]: 30 Aug 2020 16:10:07 conn_loop(): select(): max_sd = 4, t_out = 000060:000000

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@3cky @dgoo2308