After almost a year the "new" B & S grinder is in place. Found out
you could stop the table with your hand and could not get a nice slow
travel feed out of it, While trying to figure out why the PARK light
does not work, came across the wire, marked #21, from the PLC that per
the schematic should have gone to the park light, but instead went to
a Hyd solenoid. ??? That output was never energized by the PLC.
Reprogram PLC to turn t on. now the table goes really fast, Adjust
speed back to normal. It seems this valve connects the two ends of
the table cylinder together, this allows you to move the table by
hand.

I now call this valve V18 as it does not appear on any schematics or
drawings I have, either from B & S or from the guys that retofitted
the Allen Bradley PLC into this thing. It does appear in the parts
book.

Found another unused wire zip tied in the bottom of the cabinet with
#21 on it. put it to output #0. Took the solenoid wire and remarked
it #14 put it on output #15 (last one left) and added a rung to
actuate it.

Table now moves really smooth, with tons of power and can be slowed
down to a crawl.

Now to fix the rest of the problems. There is no park prox sensor so
the park command just runs the table full right to bottom out the
cylinder and stays there until you close V1. You cannot control the
cross feed. it defaults to forward and will only reverse when it hits
the forward prox. the stop button and the back button have no effect.

Plus a bunch of other minor problems, I am tring to get the machine to
behave exactly as the B & S instruction manual states.

Any B & S or PLC (A-B SLC 500) experts out there???? I need to figure
out what the Solid state relays are there for. My guess is they were
trying to overcome some shortfall of the old Modicon PLC.

Thank You,
Randy

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Randy wrote:


Any B & S or PLC (A-B SLC 500) experts out there???? I need to figure
out what the Solid state relays are there for. My guess is they were
trying to overcome some shortfall of the old Modicon PLC.

I won't call myself a Allen Bradley expert but I suspect that driving the solenoids
directly from the relatively weak relays or thyristors inside the slick is what they were
trying to avoid.

When I retrofited St. Lawrence hydraulic forming presses, every directional valve was
controlled by an auxilary relay switched by the PLC.

Wes

On Sat, 08 Nov 2008 18:44:53 -0500, Wes wrote:

Randy wrote:


Any B & S or PLC (A-B SLC 500) experts out there???? I need to figure
out what the Solid state relays are there for. My guess is they were
trying to overcome some shortfall of the old Modicon PLC.

I won't call myself a Allen Bradley expert but I suspect that driving the solenoids
directly from the relatively weak relays or thyristors inside the slick is what they were
trying to avoid.

When I retrofited St. Lawrence hydraulic forming presses, every directional valve was
controlled by an auxilary relay switched by the PLC.

Wes

Not connected that way, Triac output card goes through the relay
contacts, the relay is switched on/off by the prox sensors.

They retro fitted in the slick and kept the SSR's as they were used in
the OEM. I can only think the Gould Modicon PLC was not able to latch
an output the way they wanted and used the relays as a work around.

Thank You,
Randy

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