Idlers Are Aligned with String to 1/32

Siemens

Belt Scale Trouble Shooting Guide Belt scale Belt scale is square with Conveyor frame and (2) Idlers before and after scale are square with conveyor frame. Scale sits level with frame and is not in a bind from side to side. Bolts on scale are tight. Bolts on idler clamps are tight. Bolts on load cell are tight. Scale Idler is square to scale. Make sure shipping stops are off. Over load stop screws is set correctly (set at 30 mV max.) MBS, MUS, Weigh deck scales only. Idler clearance is at a minimum of 1/2” between frame of scale and idler frame. Load cells are clean. Load cells gap is clean. Load cells are parallel to frame of conveyor. Check wiring for cuts from load cell to junction box or integrator if not in conduit. Scale is at least (3) Idlers from feed point. Scale is at least (3) Idlers from wing pulley. Approach and retreat idler spacing between scales idler is within ¼” of each other.

Idlers Idlers are aligned with string to 1/32”. (2) before and (2) after scale idler. All idlers have been greased. Check bearings on idlers cans to make sure that they are tight and not moving form side to side or up and down. All (3) rollers on idlers are turning on scale and the approach and retreat idler when belt is empty.

Belt Belt is not to tight must have 2% sag between idlers. Belt is tracking correctly. Belt is riding in the middle of the idlers and is not going from side to side. Belt is in good condition. No cuts or tears. Belt should not have a lot of belt splices. If using heavy belt splices, check to see that when the belt slice goes over the scale the splice must lay down on all (3) rollers and turn. If using gravity take-up it must be free and smooth to move to full range. Check to make sure that return belt is not hitting the bottom of belt scale when running and at start up.

Test weights When you have multiple scales with different test weights use the same test weights each time for each scale for spanning. When running Spans on MUS and MBS belt scales make sure that the test weights are place in the same position each time. All weights must touch front bar of scale. Wiring Check junction box for water or dirt. Check junction box connections on load cell and speed sensor that the wires are tight and not touching. Check wiring in the integrator by pulling on wires at the terminal. Check to see if ground is only grounded at integrator and not at junction box. Check wiring on speed sensor for cuts from sensor to junction box or integrator if not in conduit.

Speed sensor Do you have 10-15V excitation to speed sensor? RBSS: Check to see that the wheel is turning freely. Bearings are greased. Wheel is not slipping on belt. Wheel is not riding on top of return roller. Should be 3” to 4” behind or in front of return roller. Gap between gear and pickup is .005 to .030 or business card thickness. Gear is clean. MD series or Encoder brand speed sensor: Check to see if the sensor is mounted well and allowed to move with tail pulley back and forth and is not allowed to spin. If using rubber hose and clamps, make sure that the hose is not cracked and clamps are tight. Is shaft on sensor turning freely and is clean. Check that wire is not lose in sensor.

Integrator Belt duration in integrator is set to minimum of (2) belt revolutions. Recommend (3). If belt is in bad shape recommend (5 or 6). Do not try to Zero or Span a cold belt. Belt must run a minimum of 15 minutes to allow for belt stretch. Make sure when performing Zeros and Spans that belt is 100% clean. Has load cells been balanced. Check belt speed with a stop watch or tachometer. It should match belt speed on Integrator. Recheck programming that all parameters are set correctly.

Loadcell Do you have 10V excitation to loadcells?

Zero After performing Initial Zero record values. Perform (3) routine Zeros. They must return to within +/- 0.5 if not see comments above. Record mV reading at each loadcell.

Span After performing Initial Span record values. Perform (3) routine Spans. They must return within +/- 0.5 if not see comments above. Record mV reading at each loadcell with test weights on.

Use Zero and Span mV values to see if it repeats when scale is having problems.