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Messages - rosssyscon

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1
Technical support / Re: rtd
« on: September 10, 2003, 04:04:42 AM »
We just hooked up an RTD using the diagram from page 6 of the installation guide. Rather than a 1K Ohm Pot, we have a 100 Ohm RTD. (Using T100MD-1616+)

So far it works just fine. This allows us to bypass the expensive converter. Are there any problems with this? Are we going to experience problems later?

2
Technical support / Counter
« on: September 10, 2003, 06:03:39 AM »
I am having some diffculty with the exact operation of the [DNCtr]. I am using it as a simple timer for a motor. When it times out, motor stops. I am using the built in Clk:1.0s to decrement the counter. I am using the SetCtrSV function to set the timer value.

Issues:
1) I need to be able to adjust the time on the fly. However, I can't seem to move a new value into the counter until it has been reset. ?

2) When the counter is reset, the CtrPV is equal to -01. Is there a better way to do what I am doing?

Thanks,

3
Technical support / Re: LCD Current Limiting Resistor
« on: September 10, 2003, 11:47:12 AM »
;D Thanks for confirming.

4
Technical support / LCD Current Limiting Resistor
« on: September 10, 2003, 04:45:06 AM »
We are using a 4x20 LCD display. I noticed that the 150 Ohm resistor is getting REAL :o HOT. It will burn your finger to the touch. The resistor lead is screwed under terminal 15 and the other soldered to the power wire.

Should the resitor be attached to a metal surface with some heat sink compund? ???

Thanks again,

5
Technical support / Re: PWM Impedence
« on: September 10, 2003, 11:56:08 AM »
Sorry for the confusion. WE are controlling the VFD speed via 4-20mA output. That works great.

It's the feedback signal from the VFD that is a
--> "PWM open collector analog output at 2 kHz (30V max, imped 1kOhm, 10mA max)" - or -

--> "Can be configured as a Open collector logic output (30V max, imped 100kOhm, 50mA max) "

It's a cheap drive! They have the schematic on the RC circuit. Basically, I need the impedence (Z) on input #3 to calculate the resistor size (R2) required.

Thanks.

6
Technical support / PWM Impedence
« on: September 10, 2003, 04:56:56 AM »
We are using a variable frequency drive that has a frequency output relative to output current of the drive. The input value is very flacky and unstable. We contacted the manufacutrer and they realized they had a problem. They suggest an RC circuit. Here is what they suggested.

For a 0-5VDC output, R1 = 698 ohms
R2 = 0.23 x Z, where Z is the input impedance of the digital instrument or PLC
C1 = 0.02 ? R2, select the next larger standard value of capacitance.

I have an entire page from them, but didn't want to bore you. Please advise.

Thanks again,

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