R12 Robot Manual
page
17
Electric gripper
If the electric gripper is fitted this is wired through the robot and requires no installation by the
customer but there is an external cable from the arm to the gripper. Take care not to
continuously rotate the gripper or the wire will trap or break.
Do not force the jaws of the gripper open or closed
. Only use GRIP and UNGRIP
The gripper is operated by a drive module in the controller. A variable GTYPE contains the
value 0 for a pneumatic gripper and 1 for electric gripper.
Electric grippers are controlled from output port PA bits 0 and 1 but do not write to those bits
directly. Only use the commands GRIP and UNGRIP.
GRIP puts PA 0 on. During closing PA 0 is switched on an off at approx 500Hz. Once closed
PA is left full on.
UNGRIP asserts PA 0 off and PA 1 on again at 500Hz until the gripper is open then asserts
PA 1 off.
The time allowed for GRIP and UNGRIP is a value in TGRIP in mSecs, usually 1000 mS.
E1
E2
EG12
E1
gripper is a fulcrum or scissors style operation supplied with sculpted fingers. It's normal
to glue some low friction material or foam to the inside of the fingers.
E2
is also fulcrum but has two 'jaws' with M4 screw holes. It is normal to make fingers to
match your product that screw on to these jaws.
The E2 is supplied with long screws to prevent over-closing. Without them the jasws could
over-close and jam. Just remove them when you fit your fingers.
If an E1 or E2 gripper becomes jammed at full travel remove it from the robot. On the
underside you will see two gearwheels. Turn these by hand.
EG12
is similar to the R17 EG17 with a rack and pinon mechanism resulting in parallel
motion of the jaws.
Never remove an object from the gripper by hand when it is gripping the object.
The
jaws may snap shut and jam or damage the motor.
Increasing grip speed.
The 500Hz comes about because the power is off for 1000 uSecs and on for 1000uSecs.
The on time is determined by a variable TON (try TON ?) Change with <val> TON ! A bigger
value will result in faster closure. You can then reduce the value of TGRIP.
