Siemens Milltronics BW500 Operating Lnstructions page 75

Example:
Internal totalizer 1
Given:
Then:
External totalizer 1
Given: P005 = 1 (t/h)
Then: contact closure occurs once for every 10 metric tonnes registered
For remote totalization, the contact closure duration (P643) is automatically calculated
upon entry of the design rate (P011) and remote totalizer (P638) parameters, so that the
duration of contact closure allows the relay response to track the total up to 150% of the
design rate. The value can be changed to suit specific contact closure requirements, such
as in the case of programmable logic controllers. If the duration selected is inappropriate,
the next possible duration is automatically entered.
External Totalizer Calculation Example:
Design Rate = 50 t/h (P011)
External Totalizer Resolution Selected = 0.001 (P638 = 1)
External Totalizer Contact Closure Time selected = 30 msec (P643 = 30)
External Totalizer Cycle Time = 60 msec (External Totalizer Contact Closure Time X 2)
1. Calculate the maximum number of pulses per second for the Contact Closure Time
selected (P643).
Maximum Number of pulses per second
= 1 / External Totalizer Cycle Time
= 1 / 0.060
= 16.6 (which is rounded to a whole number of 16 in the BW500)
2. Calculate the pulses per second required for the External Totalizer Resolution
selected (P638).
Pulses Per Second = Design Rate X 150%
Because the required 20.83 pulses per second is greater than the maximum 16 pulses per
second, the External Totalizer Resolution of 0.001 will not allow the External Totalizer to
track up to 150% of the design rate. The External Totalizer Resolution will have to be
increased to 0.01 or the External Totalizer Contact Closure Time will have to be
decreased.
7ML19985DK05Milltronics BW500 and BW500/L - OPERATING INSTRUCTIONS
P005 = 1 (t/h)
P631 = 4
totalizer count increments by 10 for each 10 metric tonnes registered
P638 = 5
External Totalizer Resolution X 3600
= 50 t/h X 150%
0.001 X 3600
= 20.83
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