>From eaf5ae863e3999280a570b17bf3ef3c34d586cf9 Mon Sep 17 00:00:00 2001 From: Victor Rocco Date: Wed, 3 Oct 2012 08:53:26 -0300 Subject: [PATCH] Fix modbus tcp protocol Prevents getting error "ERROR Communication time out" in HAL. A slave device that checks the "slave number" in the modbus protocol will not respond in the actual behavior, including the Delta's RTU-EN01 remote I/O device. Oficial modbus protocol specifies that. The fix is: use slave number parameter instead of 0xFF in build_request_packet_tcp(...) Checks: * Against a Delta RTU-EN01 remote I/O device. * Against same file (modbus.c) RTU protocol, function build_request_packet_rtu(...) * Against libmodbus 3.1.0 (www.libmodbus.org) low level frame debug. * Oficial Modbus protocol specification (www.modbus.org). Signed-off-by: Victor Rocco --- src/hal/user_comps/modbus.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/src/hal/user_comps/modbus.c b/src/hal/user_comps/modbus.c index ed213c2..89bef44 100644 --- a/src/hal/user_comps/modbus.c +++ b/src/hal/user_comps/modbus.c @@ -209,7 +209,7 @@ int build_request_packet_tcp(int slave, int function, int start_addr, /* Length to fix later with set_packet_length_tcp (4 and 5) */ - packet[6] = 0xFF; + packet[6] = slave; packet[7] = function; packet[8] = start_addr >> 8; packet[9] = start_addr & 0x00ff; -- 1.7.0.4