How to set pin domain(current or voltage) of UR robot with ur_msgs

edit

At the moment this does not seem to be implemented, but the pin domain can be set with the ur_hardware_interface/script_command topic. Example code:

// include
from std_msgs.msg import String 

// the function 
def apply_vacuum(self):
rospy.init_node("apply_vacum_node") 
publisher1 = rospy.Publisher('/ur_hardware_interface/script_command', String, queue_size=2)

try:
   // first 1 is the pin number and second number is the state of the pin 
    message = "sec MyProgram():" + "\n" + "set_standard_digital_out(1,1)" + "\n" + "end " + "\n"
    publisher1.publish(message)  
except rospy.ServiceException, e:
    print "Something went wrong: %s"%e

this will work but make sure you read the scripting manual for the functions that you can use in this format. make sure that you input the correct information. The format i used can be seen here.

you only need to the use the required function for the pin domain that you can find in the mentioned scripting manual in said post.