Hello!
I am designing an open source toolhead for my Ur3e.
On the electronic side I am a bit struggling with the modbus connection, which is needed to communicate with my urcap for controlling the gripper.
For the MCU I want to use a ESP module with attached camera. The tx rx lines would be converted to rs485 to use modbus mcu.
The problem:
Is the rs485 inside the robot arm line working with 5v or 3v3?
Thanks!
The Digital Inputs and outputs of the Tool I/O need at least 5.5V to trigger:
Sending to send data to a receiving unit attached to the toolhead via RS485 could be as easy as pulsing the I/Os of the toolhead to high and low.
Here is an example URscript to send a 16bit (unsigned) integer value via Digital out 9:
DO-8 and DI-8 are used to sync the communication and
def bit(input):
msb=65536
local i=0
local output=0
while i<17:
set_digital_out(8,True)
if input>=msb:
input=input-msb
set_digital_out(9,False)
else:
set_digital_out(9,True)
end
if get_digital_in(8):
out=1
end
sync()
set_digital_out(8,False)
sync()
input=input*2
output=output*2
i=i+1
end
return output
end
to send the number 10 with this method you will have to call the bit() function like this:
data = 10
data = data + 32768
# to indicate that the number is positive: 32768 = 0
bit(data)
I am not sure if this is a workaround and wether there are better methods of using a Modbus or other communication protocols with the tool I/Os but this method should work even without a URcap that creates the Modbus server.
I am new to Modbus functions with UR though so take this information with a grain of salt if I misunderstood anything I would be glad if someone would correct me