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The most common error made when setting up the Total Pulse Repeater (TPR) function
(Sections 6.02.27,34) is to request that the relay open and close too frequently (Sections 6.02.29-
30,36-37). This can cause it to remain always open or always closed.
The most common error made when setting up the relays for High/Low RATE or High/Low
SPEED Alarms (Section 6.02.27,34) is that the selected limits (Sections 6.02.31-32,38-39) are
not realistic. This causes the alarm condition to never exist or to exist constantly. Also check the
time delay before energization (Sections 6.02.33,40). The alarm condition must exist for at least
the length of the delay time before the relay will be energized.
RATE current loop outputs are non-functional…
The WP20 has four 4(or 0) to 20 milli-amp outputs that act in unison and that are proportional to
the RATE. If one or more outputs are non-functional, first place the WP20 in Bench Test Mode
(see above) and then disconnect all loads and connect a milli-ammeter to the output. The milli-
ammeter should display a value between 19 and 21 milli-amps (ma). If it displays a value other
than that, the MP400 printed circuit board (PCB) is defective. It is not field repairable. Contact
the
Tecweigh
Service or Parts Departments (Section 2.01) for assistance.
If the output(s) is verified to be 20 +/- 1 ma, further testing is required as follows:
The four RATE current loop outputs depend upon several Parameters including Base mA
(Section 6.02.20) and Rate 20mA (Section 6.02.21). With the milli-ammeter still connected,
place the WP20 in Simulation Mode (Section 6.02.01) and verify that these Parameters are
correct as follows. First adjust the Simulated RATE to the value (usually 0 RATE) that
corresponds to a 4 (or 0) ma output. Next, adjust the Base mA Parameter until approximately 4
(or 0) ma is displayed on the milli-ammeter. Now fine tune this value by adjusting the Rate
LTrim Parameter (Section 6.02.22) until the milli-ammeter reads exactly 4.0 ma. Next, change
the Simulated RATE to the value (usually xxx tons/hr) that corresponds to a 20 ma output. Now
adjust the Rate at 20mA Parameter until approximately 20 ma is displayed on the milli-ammeter.
Next, adjust the Rate HTrim Parameter (Section 6.02.23) until the milli-ammeter reads exactly
20ma. If it is not possible to perform these adjustments, the PCB is defective and needs to be
replaced. It is not field repairable. Contact the
Tecweigh
Service or Parts Department (Section
2.01) for assistance.
If the above adjustments were successful, return to Run Mode and re-connect the load(s) with the
milli-ammeter
in series
with the load(s). Under normal operation the output current displayed on
the milli-ammeter should vary in proportion to the RATE from 4 (or 0) to 20 ma. If that does not
happen, next verify that the remote devices in the current loop are “passive”, that is, they do not
provide power to the loop. Remove or replace any that are found to be non-passive. If the output
works properly with just the milli-ammeter connected, but fails with a passive load(s) connected,
the load is probably too large. The maximum load permissible is approximately 750 ohms total.
Try distributing the loads among the four current outputs. If it is a single load, a current to
current amplifier will be required to drive the load.
Another possible problem that could arise is that the current output is functional, but one or more
loads are not functional in a multi-load loop. This problem is usually caused by the loads not
being isolated. Every load in the current loop needs to be isolated except the last one (See
Section 4.05). Also refer to Section 4.01, “4-20 ma RATE current loop output”.
If all of the above fails to rectify the problem, the PCB is faulty. It is not field repairable. Contact
the
Tecweigh
Service or Parts Department (Section 2.01) for assistance.
Содержание Tecweigh 20
Страница 2: ... 1 ...
Страница 10: ... 9 2 09 I O Quick Reference Guide ...
Страница 20: ... 19 ...
Страница 24: ... 23 4 03 WY15 and WY25 Scale Wiring load cells ...
Страница 25: ... 24 4 04 HY15 and HY25 Field Wiring ...
Страница 26: ... 25 4 05 WY10 WY10HD and WY20 Scale Wiring LVDTs ...
Страница 27: ... 26 4 06 Chart Recorder Data Logger using the 4 20 ma output ...
Страница 28: ... 27 4 07 Chart Recorder Data Logger using the HFR output ...
Страница 29: ... 28 4 08 Remote Rate Total Display 4 09 Remote Tons Counter ...
Страница 30: ... 29 4 10 Radio Transceivers Local Scale Remote Processor ...
Страница 31: ... 30 4 11 Radio Transceivers Local Processor Remote PLC PC or Remote Display ...
Страница 32: ... 31 4 12 Radio Transceivers Local DC Generator Remote Processor ...
Страница 33: ... 32 4 13 Radio Transceivers Local DC Generator and Processor ...
Страница 34: ... 33 4 14 Multiple Processors to Tecweigh Multi Scale Display MSD ...
Страница 35: ... 34 4 15 Interposing Relay External 120 vac Power 4 16 Interposing Relay Internal 30 vdc Power ...
Страница 61: ... 60 SC300 PCB WY15 and WY25 SC400 PCB WY10 and WY20 ...
Страница 71: ... 70 10 01 WY10 Dimensions CHAPTER 10 DIMENSIONS ...
Страница 72: ... 71 10 02 WY10 HD Heavy Duty Dimensions ...
Страница 73: ... 72 10 03 WY15 Dimensions ...
Страница 74: ... 73 10 04 WY20 Dimensions ...
Страница 75: ... 74 10 05 WY25 Dimensions ...
Страница 76: ... 75 10 06 HY15 and 25 Dimensions ...