Jiggadoo

Configuring high speed counter card 1734-VHSC24/C with explicit messaging

7 posts in this topic

Hello! I have a problem with Allen-Bradley High Speed Counter card 1734-VHSC24/C. I need to make changes to the configuration parameter .OnValue1 (DINT) during the system is running. Now, for changing the parameter value, I need to switch off the module and this can not be done during the line is running. I think that maybe this can be done using the explicit messaging. I could not find information for this from internet, so now I ask you to help me with this item. If anyone have experience or knowledge of this, please help me. I do no have experience using explicit messaging. My configuration: Studio 5000 Logix Designer V24.00, 1756-L71S V24.11, Ethernet/IP, 1734AENTR, 1734-VHSC24/C countermodule.

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Problem solved! It is possible use message-tag and configure it with 'Module Reconfigure'. For the 'path' it must be chosen the module for which I want module reconfigure happen. My problem was that I have not given a name for the module and my message tag went always to error-state. So, I need to give name at least to the modules I am using message tags....

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Thanks for posting that followup ! That sort of thing is very helpful to future users of this Forum.

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Hi guys, good afternoon, 

I had the same problem as the friend above, but the use of Encoder is not to measure speed but terms as position reference.  But when using the PresentCounter variable, it does not seem to increase by 1 in 1, but rather seems to jump.  That is, I can not compare with my reference positions (in unit of pulses).

The module we are using is VHSC24 and configured as counter and unfiltered (for maximum speed).  The encoder we are using is programmable DFS60B (maximum limit of 10,000 PPR).  

What could be happening?

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Hi!

PresentCounter is not updating real pulses from the countercard to the PLC. This is why it is 'jumping'. Countercard is faster than the PLC reading. If you use countercard output, it will work with correct pulse amount, for comparing the pulses.

I am not sure, what you were meaning, but this is the reason for 'jumping'

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 Hi friend,

I did not understand well: "use the countercard output".  To put my problem in context, we created a packaging inspection station on a conveyor belt.  This package is 170 mm long, so when it arrives at the station, I have a trigger sensor so I can know the amount of pulses at that moment, from there I make comparisons (position) so I can inspect at a particular location.  If any packaging is defective, we expel 190 mm after the inspection station.  In other words, the accuracy I need to read on my card is 1mm, so I can't "lose" pulses.  The encoder we use is Sick DFS60B (programmable 1 to 10.000 PPR)  with a 200mm circumference / perimeter wheel.  On the VHSC24 card in the plc it is configured with 2 ms RPI (smallest possible) and in filterless counter mode.

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Hello guys,

I am running an application for packaging measurement using a sick DFS60B incremental encoder (programmable from 1 to 10000 PPR). In more detail, it passes packaging on a conveyor belt and we have created an inspection station and an expulsion station (defective packaging), so we use the encoder to check at specific points of the packaging for defects (we use special sensors to check defects). ) (there are four in total). However, the problem we are having is the following: When reading the encoder in the PLC, the same means that performs "jumps" and does not enter the windows (GRT and LES) created on the ladder, ie, as if it were not continuous. .

I understand that because the VHSC24 card works at 1 MHz in counter mode, this type of problem should not occur according to our application is not even 100 KHz. For example, our case: Using 1000 PPR and the motor speed (coupling output) is 3600 RPM (in practice it is around 1750 RPM) the frequency is calculated as follows: F = (PPR X RPM) / 60. : F = (1000x3600) / 60 = 60 KHz, ie 60 KHz is much less than 1 MHz, I think this kind of problem does not occur.

Application Info:

. Studio 5000 V31
. PLC Model: Rockwell 1769 - L19ER-BB1B CompactLogix 5370
. Encoder Card: 1734-VHSC24 / C
. Incremental Encoder: Sick, DFS60 up to 10,000 PPR and HTL Electrical Interface. Using a 200 mm circumference / perimeter wheel.
. Motor Nameplate Data: 1670 RPM, 0.37 kW / 0.5 HP, 60 Hz
. Inverter: Weg CFW500, Output Frequency 62 Hz.

Card Settings we use
RPI: 2 ms
Type: Counter, but we already use it as Encoder X1
Store Count Mode: Disabled
Filter: No Filter, but we use 50 KHz and 5 Khz filters in our tests.
Counter Attenuator: 1

Wiring Diagram VHSC24
We turn on encoder A at input 0 and encoder Aret at input 1

In logic
(Structured Text) Using the PMUL instruction to convert encoder (Pulse) data to mm scale.
(Ladder) The window comparisons part (GRT and Les) and other part of the process. We emphasize that we performed the tests also only with the reading and comparison part of the data, excluding the other parts, precisely to verify the issue of Scan, but the problem persisted.

If anyone here in the forum has some information that can help us, I would appreciate it.

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